Venus keeps the strangest clock and calendar in the solar system. It takes about 243 Earth days to turn once on its axis, and only about 225 Earth days to travel all the way around the Sun. On Venus, in other words, the day is longer than the year. The planet finishes a lap of the Sun before it has finished a single rotation.
It gets stranger from there, and the figures are worth pulling apart, because two different “days” are hiding in this story.
Two kinds of day
The 243-day figure is the time Venus takes to spin once relative to the distant stars, what astronomers call a sidereal rotation. It is the true turn of the planet on its axis.
But a day in the everyday sense is the gap between one sunrise and the next, and on Venus that is a different and shorter span: about 117 Earth days. The two numbers disagree because Venus is moving around the Sun while it spins, and its spin is unusually slow, so the Sun’s position in the sky is set by a tug-of-war between the planet’s rotation and its orbit rather than by rotation alone. The result, according to NASA’s figures, is a solar day of roughly 117 Earth days. Sunrise to sunrise takes nearly four Earth months.
Rising in the west
There is one more oddity, and it is the one most people have heard. On Venus the Sun comes up in the west and goes down in the east, the reverse of what it does here.
This is because Venus rotates backwards. Nearly every planet, Earth included, spins in the same direction it orbits, which is why our Sun rises in the east. Venus turns the other way, a motion called retrograde rotation, effectively almost upside down compared with its neighbours, its axis tipped close to 180 degrees. It is also the slowest-spinning planet in the solar system, which is part of why its day runs so long. From the surface, the Sun’s daily path would run the opposite way across the sky.
Why it spins like this is not settled. The leading ideas involve either a colossal ancient impact that flipped or reversed the planet, or the slow grinding action of solar tides on its massive atmosphere over billions of years. Both remain hypotheses.
What you would actually see
Here the romantic image needs a caveat, because nobody on Venus would watch a crisp sun lift over a western horizon.
The planet is wrapped in a dense atmosphere of carbon dioxide topped with thick clouds of sulphuric acid, and almost no direct sunlight reaches the ground as a clear beam. A surface observer, if one could survive the 460-degree heat and crushing pressure, would experience a slow, dim brightening and fading of a uniformly glowing sky over those 117 days, rather than a disc rising at a point on the horizon. The direction of the Sun would be a smear of light, not a sunrise you could photograph.
That does not change the underlying mechanics. The Sun’s light still tracks east to west across that murky sky, just without a sharp Sun to mark it.
A planet out of step
Put together, Venus runs on a schedule that breaks every habit Earth has taught us. The day outlasts the year. The Sun, such as it is, rises in the wrong place. And the time from one dim dawn to the next is counted in months, not hours.
None of these are quirks of measurement or rounding. They follow directly from a planet that turns slowly, backwards, beneath a sky that never clears, which is a fair summary of how thoroughly Venus refuses to behave like home.
When NASA’s Parker Solar Probe passed through the solar corona during perihelion encounters at the heliospheric current sheet, its instruments recorded energetic protons at energies far above what existing models of particle acceleration at that location could account for.
A team led by Mihir Desai at the Southwest Research Institute, with James Drake, Marc Swisdak, and Zhiyu Yin from the University of Maryland’s Institute for Research in Electronics and Applied Physics has published an analysis of those measurements in The Astrophysical Journal Letters, identifying magnetic reconnection at the heliospheric current sheet as the mechanism responsible. The proton energies detected were, in the study’s framing, approximately a thousand times greater than the available magnetic energy per particle that models of this process had predicted.
The finding matters for two reasons: it identifies a source of energetic particles close to the Sun that was not anticipated, and it raises questions about how far the existing understanding of reconnection-driven particle acceleration extends.
What Parker measured at the current sheet
The heliospheric current sheet is a vast, warped surface in the solar wind where the Sun’s magnetic field reverses polarity. Parker crosses it during perihelion passes, when the spacecraft dips inside the corona. At those distances, the current sheet is narrower and more structured than it appears in the near-Earth solar wind, and the reconnection events occurring there have characteristics that instruments further from the Sun cannot resolve.
Within the exhaust region downstream of a reconnection event, where magnetic field lines have broken and rejoined and the released energy is being distributed into the surrounding plasma, Parker detected trapped protons at energies up to approximately 400 keV. The particles were confined within magnetic islands, structures that form within the reconnection exhaust as reconnected field lines roll up into closed loops. Magnetic island merging, as those loops interact and combine, appears to be the mechanism that accelerated the protons to the observed energies.
The thousand-fold discrepancy between what the models predicted and what Parker measured is the number that requires explanation. Reconnection as a particle accelerator was not a new idea: the process has been theorised to play a role in accelerating charged particles in a range of astrophysical environments. What was not predicted was that the energisation within near-Sun reconnection exhaust could reach this level through the island-merging pathway.
Why this source was not in the models
Current models of solar energetic particles, the high-speed charged particles that propagate through the solar system and can affect spacecraft and astronauts, have generally attributed the most energetic events to large-scale shocks: the driven shock fronts of coronal mass ejections, and the slower-building shocks of co-rotating interaction regions. Reconnection at the current sheet was considered a secondary contributor at best, capable of producing modest particle energies close to the Sun but not a major accelerator of the particles that eventually arrive as energetic storm particle events near Earth.
The Parker measurements suggest that picture needs revision. The magnetic island merging mechanism Desai and colleagues identify can evidently produce proton populations at energies that challenge the boundary between what reconnection does and what shock acceleration does. Whether this source can explain a significant fraction of observed near-Earth energetic particle events, or whether it contributes mainly at energies and scales that remain confined close to the Sun, is a question the paper does not yet resolve.
What this adds to the corona heating problem
A separate thread connects to the longstanding question of why the solar corona is so much hotter than the surface below it. The corona reaches temperatures of several million degrees Celsius while the photosphere sits at around 5,500°C. The energy source sustaining that gradient has not been fully identified. Reconnection, along with wave heating, is one of the leading candidates.
If reconnection at the current sheet is producing particles at the energies Parker measured, it is also depositing energy into the surrounding plasma at rates that may be higher than the models assumed. That does not resolve the corona heating problem, but it shifts the accounting. The energy going into particle acceleration through magnetic island merging is energy that must come from somewhere in the magnetic field, and tracing it may tighten the constraints on how much reconnection contributes to coronal heating overall.
Drake and Swisdak contributed the reconnection theory component of the analysis. The collaboration between the observational data from Parker and the theoretical modelling capacity at the University of Maryland is the structure the paper’s analysis rests on.
What comes next
Parker Solar Probe has now completed more than two dozen perihelion passes, with each close approach yielding data at distances and speeds no prior mission could reach. The heliospheric current sheet crossings that provided the data for this paper are repeatable: Parker will continue to encounter the current sheet during future perihelia, allowing the team to look for the magnetic island signature in additional events and test whether the particle energies observed here hold up as a consistent feature rather than a single anomaly.
Solar Orbiter, the European Space Agency mission operating in coordination with Parker, offers complementary measurements at somewhat greater distances. Comparing what the two spacecraft measure of the same particle populations as they propagate outward from the Sun will help establish which features originate close to the source and which are modified by the intervening solar wind. The energetic particle observations that puzzled researchers in the pre-Parker era now have a candidate mechanism. Whether that mechanism accounts for a large or small fraction of what actually reaches Earth remains the open question.
The Murchison meteorite is, by every available measure, one of the more scientifically valuable single rocks ever to fall on the planet. The fireball that delivered it streaked across the sky above the Goulburn Valley in southeastern Australia on a Sunday morning in September 1969, broke apart at high altitude, and scattered fragments across a roughly 35-square-kilometre area of farmland. One piece punched through the roof of a hay shed. The local dairy farmers who recovered most of the fragments over the following weeks sold the bulk of them to museums and universities, with the largest single collection now held by the Field Museum of Natural History in Chicago. Approximately 80 kilograms of the original 100-kilogram fall is currently held in scientific collections around the world. Over the subsequent five decades, Murchison has been examined more intensively than almost any other meteorite — yielding more than 70 distinct amino acids (including some that do not occur in any known terrestrial biology), sugars including ribose (the backbone of RNA), and several of the nucleobases that make up the building blocks of DNA. The rock has been at the centre of multiple revisions to scientific understanding of how organic chemistry distributes itself through the early solar system.
According to NBC News’s coverage of the 2020 Heck et al. paper on presolar grains in Murchison, the team published its dating results in the Proceedings of the National Academy of Sciences in January 2020. The analysis used a technique called cosmic-ray exposure dating, which Heck described with an unusually accessible analogy: cosmic rays — high-energy particles that constantly stream through the galaxy — interact with solid matter and produce new elements at a roughly constant rate. The longer a particle of matter has been drifting through space exposed to cosmic rays, the more of these new elements accumulate inside it. “I compare this with putting out a bucket in a rainstorm,” Heck told reporters at the time. “Assuming the rainfall is constant, the amount of water that accumulates in the bucket tells you how long it was exposed.” Applying this method to 40 large silicon-carbide grains extracted from the Murchison fragments, the Heck team was able to estimate how long each individual grain had been drifting through interstellar space before being incorporated into the asteroid that eventually fell to Earth.
What presolar grains actually are
The grains the Heck team dated are called presolar grains — solid particles that formed in the atmospheres of dying stars before the solar system existed, drifted through the interstellar medium for hundreds of millions or billions of years, and were then incorporated into the molecular cloud from which the Sun and planets eventually condensed. As reported in Sci.News’s coverage of the same paper, the typical formation environment for the silicon-carbide grains examined by the Heck team was the slowly-expanding atmosphere of an asymptotic giant branch (AGB) star — a red giant in the late stages of its evolution, shedding its outer layers into space at a rate of roughly one solar mass every hundred thousand years. The carbon, silicon, and other elements in the stellar atmosphere condense as the gas cools and expands, forming microscopic dust grains that are then carried outward by the stellar wind into the surrounding interstellar medium.
Most of these grains, once released into space, are eventually destroyed by some combination of supernova shock waves, radiation, and chemical reprocessing within the molecular clouds where new stars form. A small fraction survive intact for billions of years, drifting through the galaxy as part of the general inventory of interstellar dust. When a new solar system begins to form by gravitational collapse of a dense region of interstellar gas, this dust is incorporated into the early protoplanetary disc — and the heat and chemistry of solar system formation typically destroys or substantially alters most of it. The grains that survive intact through the entire formation process do so because they are extraordinarily durable (silicon carbide is one of the hardest materials in nature) and because they are quickly incorporated into the deep interiors of primitive asteroids that never undergo significant thermal processing. Murchison’s parent body was one such asteroid. The grains inside the Murchison fragments are, in a literal sense, time capsules from before the solar system existed.
The age distribution
The headline figure from the Heck team’s analysis — that the oldest grains are approximately 7 billion years old, predating the solar system by approximately 2.5 billion years — captures the extreme of the distribution rather than the average. Per ScienceDaily’s coverage of the Field Museum announcement, the full age distribution of the 40 grains was substantially more informative than the single extreme number suggests. Approximately 60 percent of the grains formed between 4.6 and 4.9 billion years ago — in the few hundred million years immediately preceding the formation of the solar system. Approximately 10 percent formed more than 5.6 billion years ago. A small number formed at the extreme end, around 7 billion years ago. Every grain examined was, by the cosmic-ray exposure dating, older than the 4.6-billion-year-old Sun. This is what made them presolar.
The distribution itself carries scientific weight beyond the individual grain ages. The clustering of a substantial fraction of grains in a narrow age band suggests that an unusual number of stars in the Milky Way galaxy formed, lived their full life cycles, and died during a specific epoch several billion years before the Sun ignited — a “burst” of star formation that produced an unusually large population of dying stars whose outflows seeded the surrounding interstellar medium with the dust that would later contribute to the formation of the solar system. The Heck team’s interpretation, drawing on the age distribution, is that this burst occurred approximately 7 billion years ago. The implication is that the Sun and the planets formed, several billion years later, from a galactic environment that had been substantially enriched with material from this earlier generation of stars.
Why no comparable material exists on Earth
As reported by Malay Mail’s coverage of the age distribution, the broader reason presolar grains can only be found in meteorites — never in any rock of terrestrial origin — is that every piece of solid material that contributed to Earth’s formation has subsequently been heated, melted, recrystallised, or otherwise reprocessed by the geological activity of the planet itself. Plate tectonics has churned the entire crust through the mantle and back at least once. Volcanism has melted and re-erupted vast quantities of material. Even the oldest rocks on Earth, found in places like the Acasta Gneiss Complex in northern Canada, are at most 4.0 to 4.2 billion years old — substantially younger than the planet itself, and far younger than the presolar grains preserved inside primitive meteorites.
The Murchison meteorite, in this respect, occupies a peculiar epistemological position. It is the closest available physical sample of the early solar system, but it is also a sample of the pre-solar-system galaxy that produced the early solar system. The grains inside it are older than anything that can be found by digging downward through the rocks of Earth, by any depth or any drilling technology. They are, in essence, a sample of the chemistry of the Milky Way at a moment several billion years before any of the familiar features of the current solar system existed. The fragments collected by Australian dairy farmers in 1969 and sent to museums in Chicago and elsewhere have turned out to contain, embedded in their carbonaceous matrix, a small but real sample of stardust from stars that finished burning before the Sun began.
In 1950, the United States Census Bureau estimated that approximately 2,300 Americans were aged 100 or older. The total population of the country at the time was approximately 152 million, which made centenarians one of the rarest possible demographic categories — approximately one in every 66,000 Americans had reached the age. By 1990, the centenarian count had risen to approximately 37,000. By 2020, it had reached approximately 92,000. By 2024, it had passed 101,000. The trajectory has been steep and accelerating, and the demographic shift now visible in the centenarian numbers is one of the larger long-term changes in the structure of the American population — a category that was statistically negligible at the end of World War II is now projected to become, within the lifetimes of most people reading this, a substantial demographic constituency in its own right.
According to the Pew Research Center’s January 2024 analysis of Census Bureau projections, the US centenarian population is projected to more than quadruple from approximately 101,000 in 2024 to approximately 422,000 by 2054 — meaning that within the next 30 years, the proportion of Americans aged 100 or older will rise from approximately 0.03 percent of the population to approximately 0.1 percent. This is the official Census base-case projection. Higher-end estimates developed by demographic researchers — including the MacArthur Foundation Research Network on an Aging Society — have projected substantially higher numbers under more optimistic mortality-improvement scenarios, with some estimates exceeding 1.8 million US centenarians by mid-century and substantially larger numbers by 2100. The range between the Census base case and the higher-end projections is large, and the actual outcome will depend on whether mortality improvements at older ages continue at recent rates, accelerate, or plateau.
What is driving the projected growth
The proximate driver of centenarian growth is not improving mortality among the young or middle-aged — those mortality rates are already very low and have only modest room to fall. The driver is sharply declining mortality among nonagenarians: people aged 90 to 99 who, in previous generations, would typically have died before reaching 100. The mortality rate among 90-year-olds has been falling steadily across developed countries for decades, with each successive cohort of nonagenarians surviving slightly longer than the previous one. The result is that the share of any given birth cohort that eventually reaches 100 has been rising, and the absolute number of centenarians is rising even faster because the population at risk (the 90-year-olds in the country) has also been growing rapidly.
Per a CEOWORLD analysis of the global centenarian surge, the same pattern is visible internationally. The United Nations estimated approximately 722,000 centenarians worldwide in 2024 and projects that the number will rise to approximately 4 million by 2054 — a nearly six-fold global increase in 30 years. By mid-century, the largest national centenarian populations are projected to be China (approximately 767,000), the United States (approximately 422,000), India, Japan, and Thailand, with several Southeast Asian countries and parts of southern Europe showing particularly rapid centenarian growth on a per-capita basis. Japan, currently the country with the world’s highest median age, is projected to have approximately 40 centenarians per 10,000 people by 2054 — meaning that roughly one in every 250 Japanese residents will be aged 100 or older. Thailand is projected to have an even higher ratio, at approximately 49 per 10,000.
The contested longer-term projections
The substantive disagreement among demographers is not about whether centenarian numbers will rise — that is now essentially settled — but about how far they will rise, and how soon a majority of births in low-mortality countries will produce people who eventually reach 100. The optimistic position, associated with the demographer James Vaupel and colleagues at the Max Planck Institute for Demographic Research, holds that life expectancy in the most advanced countries has been increasing by approximately three months per year for the past 150 years and shows no clear sign of slowing — and that this trajectory implies that the majority of children born in low-mortality countries today will live to see their hundredth birthday. The skeptical position, associated most prominently with the American demographer S. Jay Olshansky and his collaborators, holds that life expectancy gains are now slowing substantially in the United States and other developed countries, that the easy mortality reductions from infectious disease control, smoking declines, and cardiovascular medicine have largely been achieved, and that further gains will be substantially harder to obtain.
The empirical evidence for the slowdown position has become more visible in recent years. US life expectancy peaked at approximately 78.9 years in 2014 and then declined — partly because of the opioid crisis, partly because of rising obesity-related mortality, partly because of COVID-19 mortality during the pandemic, and partly because of slowing gains in cardiovascular medicine. The current US life expectancy of approximately 76 years is substantially below the trajectory that the Vaupel projections would have predicted. As covered by a foundational MacArthur Foundation Research Network paper on demographic forecasts for the United States in the 21st century, the higher-end centenarian projections depend on assuming that the recent slowdown is temporary and that the longer-run Vaupel-style trajectory will resume. Whether it does is one of the central empirical questions in contemporary demography, and the answer will substantially affect both the centenarian counts in 2054 and the much larger projections for 2100.
The maximum lifespan question
As reported by a 2021 Bayesian analysis published in Demographic Research by Michael Pearce and Adrian Raftery at the University of Washington, the related question of what the maximum human lifespan will reach by 2100 is approachable with statistical methods even where the underlying biology is uncertain. The Pearce-Raftery analysis modelled the existing distribution of supercentenarians (people aged 110 or older) and the projected growth of that population through the rest of the century, and estimated that there is greater than 99 percent probability that the current record human lifespan — Jeanne Calment of France, who died in 1997 at 122 years and 164 days — will be broken before 2100. They estimate an 89 percent probability that someone will reach age 126, a 44 percent probability that someone will reach 128, and a 13 percent probability that someone will reach 130. These projections are not predictions about the typical lifespan but about the extreme tail of the survival distribution, which depends on the same nonagenarian mortality declines that drive the centenarian numbers.
The deeper question that the centenarian projections raise is the relationship between living longer and living well. The available evidence on healthspan — the proportion of life spent in good health, rather than in disability or substantial decline — suggests that healthspan has been increasing more slowly than lifespan. The result is that the gap between the two has been widening: people are living longer, but with more years of substantial disability, more years of cognitive decline, and more years of dependence on caregivers and the healthcare system. The economic implications are substantial. The current pension systems, healthcare systems, and family structures of most developed countries were built around assumptions about average lifespan and the typical duration of post-retirement life that no longer hold. The institutional response, across most of the developed world, has been slower than the underlying demographic shift. Whether the eventual centenarians — including, possibly, a substantial fraction of the children born this year — will arrive at their hundredth birthdays in good health, in supported decline, or somewhere in between will depend on whether the gains of the coming decades are made primarily in extending lifespan or primarily in extending healthspan. The two trajectories produce very different futures.
The popular framing of the question — why has no human walked on the Moon since 1972? — usually proceeds as though there is some technical answer to be found. The rockets must have stopped working. The engineering must have been forgotten. The expertise must have been lost in the half-century since Apollo 17 splashed down. The actual answer is substantially simpler and substantially less satisfying. The Apollo programme was not cancelled because it stopped being possible. It was cancelled because it stopped being useful for what it had been built to accomplish. The capability question is a downstream consequence of a political question that was settled in the early 1970s, when the American government decided that the goal of beating the Soviet Union to the Moon — having been achieved on 20 July 1969 with Apollo 11 — was no longer worth paying for, and that the remaining momentum of the Apollo programme should be redirected toward other priorities.
According to the Smithsonian National Air and Space Museum’s editorial reconstruction of the Apollo cancellations, the decisions to end the lunar programme were made in a sequence that began almost immediately after Apollo 11’s success. By December 1969 — five months after Neil Armstrong’s first footstep — one of President Richard Nixon’s top aides told NASA that “the President says that he doesn’t have enough money within the next couple of years and must accept limitation of [space] activity” and that Nixon “did not see the need to go to the moon six more times.” On 4 January 1970, the Apollo 20 mission was formally cancelled. In September 1970, Apollos 18 and 19 followed. The remaining missions — Apollos 14 through 17, the latter three already in advanced preparation — were allowed to proceed and were completed by December 1972. The Saturn V production line was shut down in 1970. The remaining unflown Saturn Vs were sent to museums, where they remain as the largest functional rockets ever built, permanently grounded.
Why the political momentum collapsed
The Kennedy speech of 25 May 1961 — “I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth” — was framed in terms of national capability and human aspiration, but the actual policy logic that funded it was strategic competition with the Soviet Union. The Soviets had launched Sputnik in 1957, put Yuri Gagarin into orbit in April 1961 (six weeks before Kennedy’s speech), and were widely perceived to be ahead of the United States in space capability. The Apollo programme was, in essential terms, a national project to recover technological prestige from a position of perceived inferiority. It was funded at scales that no comparable peacetime project before or since has matched — peaking at approximately 4.4 percent of the entire US federal budget in 1966.
The strategic logic for that funding evaporated essentially the moment Armstrong stepped off the lunar module ladder in July 1969. The Soviets, by 1969, had already effectively conceded the lunar race — their N1 super-heavy rocket failed in four successive test launches between 1969 and 1972, and the Soviet crewed lunar programme was wound down quietly. There was no longer any external competitor to beat. There was no longer any strategic prestige to be gained from continued lunar landings. And the public, which had supported Apollo as a Cold War project, had never developed the underlying enthusiasm for lunar exploration as a scientific or exploratory enterprise that would have been required to sustain funding in the absence of the Cold War rationale. Polls throughout the late 1960s consistently showed that a majority of Americans thought Apollo was not worth the cost, even at the peak of the programme’s popularity.
The internal NASA decisions
Per The Planetary Society’s analysis of how Nixon shaped the post-Apollo NASA, the popular blame placed on Nixon for ending Apollo is partially deserved but oversimplifies the institutional dynamics. NASA itself, under Administrator Thomas Paine, agreed to terminate Saturn V production and cancel later Apollo missions in order to free up budget for the post-Apollo programmes the agency wanted to pursue — an experimental space station that would become Skylab, and a reusable spacecraft that would become the Space Shuttle. The choice was framed within NASA as a redirection of resources from the now-completed lunar landing programme toward new objectives, rather than as an abandonment of human spaceflight. The institutional case for shutting down the Saturn V line was that it was no longer needed for the missions the agency intended to pursue, and that maintaining a manufacturing line for a rocket the agency was not going to use would have consumed budget that could be spent on the Shuttle.
That decision turned out to be one of the more consequential institutional choices of the post-Apollo era. The Shuttle programme that NASA selected as its successor to Apollo was, by every available assessment, a substantially less ambitious vehicle than what the Saturn V could have supported, while also being substantially more expensive per launch than Apollo had been. The Shuttle operated from 1981 to 2011, completed 135 missions, lost two crews and 14 astronauts in catastrophic accidents, and never carried humans beyond low Earth orbit. The capability that had allowed twelve men to walk on the Moon between 1969 and 1972 was, by the time the last Saturn V was sent to a museum in the mid-1970s, no longer institutionally sustainable. Restarting it would require essentially rebuilding the entire programme from scratch — which is what NASA’s Artemis programme has, in fact, been attempting to do for the past several years, at substantial cost and with substantial delays.
What “lost capability” actually means
As covered by AmericaSpace’s detailed history of the Apollo cancellations, the popular claim that humanity “lost the capability” to return to the Moon is partially true and partially misleading. The engineering knowledge from Apollo was documented and survives in archives, technical reports, and the institutional memory of the relatively small number of engineers from the era who are still alive. The capability that was lost is not the knowledge itself but the institutional infrastructure that supported it: the Saturn V manufacturing line, the supplier networks, the specialised workforce, the test facilities, and the political-economic configuration that allowed roughly 400,000 people working across NASA and its contractor network to be mobilised on a single objective with a national-priority budget. None of these things are recoverable in their original form. They have to be rebuilt, which is essentially what the Artemis programme is now doing, and which is partly why the rebuild has taken decades and substantially exceeded its original budget.
The deeper point is that the question “why has no one been back to the Moon in fifty-three years?” has the same answer as the question “why was anyone there in the first place?” The Apollo programme was a Cold War project that happened to produce, as a byproduct, the most ambitious feat of exploration in human history. When the Cold War rationale for the project ended, the project ended. The capability that had been built for the project was allowed to decay because the institutional reasons for maintaining it had decayed first. The current revival of crewed lunar exploration — through Artemis, through China’s parallel programme, through the commercial-spaceflight ecosystem that has emerged over the past decade — is taking place because new institutional reasons have emerged: geopolitical competition with China, commercial interest in lunar resources, scientific interest in the lunar south pole, and a renewed sense in several capitals that human presence beyond Earth orbit is strategically valuable. Whether the new reasons will sustain a sustained human presence on the Moon, or whether the next round of lunar landings will be followed by another half-century pause, depends on whether the institutional infrastructure being built now is durable enough to survive the eventual evaporation of whatever specific political momentum is currently funding it. The Apollo experience suggests that this is not a question to be answered with technological optimism.
Olympus Mons on Mars is the tallest volcano in the solar system, rising about 22 kilometres above the surrounding plains, roughly two and a half times the height of Mount Everest. You might expect the largest mountain anywhere to be the most dramatic thing on the horizon. It is almost the opposite. Stand on its slopes and you would probably not register that you were on a mountain at all.
The reason is not the height. It is the width.
Big in a way that hides itself
Olympus Mons is roughly 600 kilometres across, a footprint about the size of the US state of Arizona, broader than a good many countries. It is a shield volcano, built from countless runny lava flows rather than explosive eruptions, and that gives it an extremely gentle profile. Its flanks rise at only a few degrees, the slope of a shallow ramp rather than a peak.
Put those two facts together and the mountain defeats the eye. The summit of a 600-kilometre-wide dome sits so far away from anyone on the flanks, and the ground tilts so gently, that the curve of Mars carries the high ground below the horizon. Mars is a smaller world than Earth, so its horizon is closer to begin with, and Olympus Mons is far wider than that horizon. From most of its slopes you would see a faintly tilted plain running off into the distance, not a summit ahead of you.
It is less a mountain you look at than one you would cross without quite noticing.
Why it grew so large
The size comes down to how Mars is built. Earth’s crust is broken into plates that drift slowly over the hot interior, so a volcanic hotspot does not stay under the same patch of surface for long. As the plate moves, the hotspot punches out a string of separate volcanoes instead of one, which is how the Hawaiian island chain formed.
Mars, as far as we can tell, has no such moving plates. Its crust sits still over the heat below, so eruption after eruption piled lava onto the same spot for a very long time, stacking up a single colossal shield rather than spreading the output across a chain. Lower Martian gravity, which lets a pile of rock stand taller before it collapses under its own weight, helped it grow further.
The drama is at the edge
There is a twist worth knowing. The one part of Olympus Mons that does look like a sheer mountain is not the summit but the rim.
The whole volcano is ringed by a steep escarpment, a cliff in places several kilometres high, where the gentle flanks end abruptly and drop to the plains below. A traveller approaching from outside would meet a wall of rock taller than most mountains on Earth. Climb it, and the dramatic relief would stop. Beyond the rim lies the long, mild upward slope that hardly reads as a climb at all. Far away at the very top, out of sight from almost anywhere on the flanks, sits a complex of overlapping craters, the collapsed calderas of past eruptions, together spanning roughly 80 kilometres.
A mountain too big to see
This is the strange thing about superlatives at planetary scale. The biggest mountain in the solar system is also one of the hardest to perceive as a mountain, because it is built on a scale the human eye was never meant to take in from the ground.
From orbit, Olympus Mons is unmistakable, a vast blister on the face of Mars. From its own slopes, it would mostly just be the ground, sloping away, with the rest of the mountain hidden over the edge of a smaller world.
One whale skeleton on the deep seafloor can host an entire neighbourhood of animals. On whale skeletons studied, researchers have found as many as 190 species of macroscopic bottom-dwelling animals on a single skeleton. Biologists call the phenomenon a whale fall, and the name is almost literal: a body falls, and an oasis assembles around it.
The setting matters. The abyssal plain is one of the hungriest places on Earth, a soft floor that lives on whatever scraps drift down from sunlit water far above. A great whale arriving intact is a sudden windfall, tens of tonnes of food dropped onto a surface that normally goes without.
What follows is a sequence of feasts, each handing off to the next over years.
What actually happens to the body
Researchers describe the process in overlapping stages. First come the mobile scavengers. Hagfish, sleeper sharks, crabs and their kind strip the soft tissue, a stage that can run up to two years for a large animal. Once the flesh is gone, a wave of smaller opportunists settles onto the bared bones and the enriched sediment around them.
In what is called the sulfophilic stage, bacteria break down the fats locked inside the skeleton and release hydrogen sulphide, one of the same chemical currencies that helps fuel life at hydrothermal vents and cold seeps. The Smithsonian describes this final stage as the point when bacteria break down lipids trapped inside the bones, generating sulfur and supporting a larger community of rare species.
That chemistry can sustain a community of chemosynthetic animals for a long time. The Natural History Museum puts this stage at roughly 10 to 50 years, and one large whale-fall community has been tracked for more than 50 years.
The worms that eat bone
The bones themselves turned out to shelter one of the stranger residents in the deep. In 2002, on a whale fall about three kilometres down in Monterey Canyon, scientists found a new genus of worm they named Osedax.
Adrian Glover, a deep-sea biodiversity researcher at the Natural History Museum in London, calls them “the most important animals responsible for the process of breaking down the bones,” though the large scavengers do plenty of reducing earlier on.
An individual Osedax can spend as long as about a decade feeding on a single whale’s bones. That figure is worth holding against the popular claim that the worms gnaw for the better part of a century: the documented number for an individual worm is closer to ten years, not eighty.
What made the worms possible is the strange economy of the deep. As Robert Vrijenhoek, the MBARI evolutionary biologist who led the discovery, put it: “When carcasses fall to the bottom of the ocean, there are no hyenas down there to eat the bones.” Osedax is the exception that filled the gap.
How many are down there right now
For all that researchers know about how whale falls work, almost no one has watched a natural whale fall unfold from death and sinking through the whole ecological succession. Fujiwara et al. note that, since the first observations in 1987, several natural whale falls have been opportunistically encountered during remotely operated vehicle, submersible and trawl deployments.
For years, one of the deepest confirmed natural examples was an Antarctic minke whale resting at 4,204 metres in the South-West Atlantic. Just this month, researchers reported active whale-fall ecosystems in the Diamantina Zone of the southeastern Indian Ocean, including one at 6,789 metres, pushing the known depth range far beyond that earlier record.
When Vrijenhoek’s team found unexpected genetic diversity in their bone-eating worms, the result led him to a simple inference: “there must be a lot of dead whales out there.” That was a deduction from genetics rather than a count, and even with new discoveries, the watched record remains tiny compared with the deep ocean itself.
The honest answer to how many active whale falls are feeding deep-sea communities at this moment is that no one really knows, only that the number seen by human eyes is a sliver of the number that must be there.
Frances Gerety was a copywriter at the Philadelphia agency N.W. Ayer & Son when she sat down late one night in 1947, exhausted, and scrawled four words on a notepad before going to bed: A diamond is forever. She nearly forgot them by morning. The line would run on De Beers advertisements for decades, get crowned the greatest advertising slogan of the twentieth century by Advertising Age in 1999, and rewire the global engagement ritual so completely that the diamond ring became something close to a biological assumption. Gerety herself, who wrote the most successful marriage proposal in commercial history, lived alone and never married.
She worked at N.W. Ayer for her entire career, from 1943 until her retirement in 1973, on a single account: De Beers. For three decades, almost every piece of copy that sold a diamond in the United States passed through her typewriter. She was the only woman in the agency’s copy department when she was hired, and she stayed the only woman on the De Beers account for most of that run.
The night the line arrived
The story Gerety told later was unglamorous. She had a presentation the next morning and had not yet written a tagline for the new campaign. She was tired. She put her head down on her desk and asked, by her own account, for some help from above. Four words came. She wrote them on a slip of paper and went to sleep.
The agency’s creative director was unimpressed at first. The grammar bothered people — are forever, surely, not is. Gerety held the line. The singular verb gave the sentence the weight of a proverb instead of a sales pitch, and that was the whole point. De Beers signed off. The slogan ran for the first time in 1948.
What the line was actually doing
To understand why the four words mattered, you have to understand what De Beers was up against in 1947. Diamond sales had collapsed during the Great Depression. The average American engagement ring in the 1930s contained no diamond at all, or a small chip mounted in a thin band. The South African mining cartel, sitting on enormous stockpiles, hired N.W. Ayer in 1938 to do something unprecedented: not advertise a brand, but invent a custom.
The campaign that Gerety inherited and then defined had two jobs. First, convince young men that a diamond ring was the only acceptable way to propose. Second, convince young women that a ring without a diamond meant they were not truly loved. The slogan she wrote in 1947 accomplished both at once. If a diamond is forever, then so is the marriage it represents — and so is the reason you cannot resell it, which was the quiet commercial masterpiece of the line. A diamond you would never part with is a diamond that would never flood the secondhand market and crash De Beers’ carefully managed prices.
By the 1950s, the majority of American brides received a diamond engagement ring. The number kept climbing. By the late 1990s the practice had become standard in the U.S. and had spread to Japan, where the diamond engagement ring had been essentially unknown before Ayer’s campaign arrived in the 1960s. Within two decades, a majority of Japanese brides were also wearing diamonds.
The greatest slogan of the century
In 1999, as advertising trade publications compiled their end-of-century lists, Advertising Age ranked the top slogans of the twentieth century. A diamond is forever took first place. The judges noted that no other slogan had so thoroughly created the market it served. Most advertising sells a product into an existing desire. Gerety’s line manufactured the desire.
She was in her eighties and watched the announcement from her home in Philadelphia. She had retired three decades earlier. The line was still running, unchanged, on every De Beers campaign worldwide.
The copywriter herself
Frances Gerety was born in Philadelphia in 1916. She studied at Bryn Mawr College and joined N.W. Ayer in 1943, at a moment when wartime labor shortages had cracked open copywriting rooms to women who would have been turned away five years earlier. She kept the job after the war, which was less common, and her colleagues described her as quiet, professional, and obsessively careful about the cadence of a sentence.
She lived in a small house in Philadelphia. She kept dogs. She traveled. She did not, by every available account, ever come close to marrying. She told a colleague once, with characteristic dryness, that she had spent her career persuading other women to do something she had decided against.
The irony nobody made her explain
The temptation, looking back, is to read the gap between Gerety’s professional output and her private life as some kind of secret wound. The concept of achievement wounds tends to frame high-output creative careers as compensations for absences in personal life, and biographers love that frame because it gives a tidy arc. Gerety’s contemporaries did not describe her that way. They described someone who liked her work, liked her independence, and treated the De Beers account as a professional puzzle rather than a personal project.
Building on the distinction between achievement and accomplishment — achievement as the metric, accomplishment as the internal sense that the work was worth doing — Gerety, by every account from people who worked with her, had both, and never seemed to need her own life to mirror the lives she was selling.
The pull to read her biography as ironic comes from how people interpret others’ contradictions. Audiences see a single salient fact — copywriter sells marriage, copywriter never marries — and lock it into a narrative shape because the shape is more memorable than the messy truth. The truth is that Gerety was a working professional in a creative field who happened to be very good at one specific assignment and happened to live a private life that did not match the assignment.
Why the slogan stuck
Linguists and advertising scholars have spent decades trying to explain why four words written at the end of a long workday became one of the most replicated commercial sentences in history. Some of it is the grammar — the singular is, which Gerety insisted on, makes the sentence sound like an axiom rather than a claim. Some of it is the rhythm: three short syllables, a pause, three more. Some of it is the way the line refuses to mention the buyer, the seller, the price, or the act of purchase.
The slogans which embed themselves most deeply in memory tend to function as small proverbs — sentences that feel pre-existing rather than written. They borrow the cadence of folk wisdom. Gerety’s line does this almost perfectly. It sounds like something your grandmother might have said, even though your grandmother probably first heard it from a magazine ad in 1948.
The brevity of four-word phrases sits inside the comfortable range of working memory and can be retrieved with almost no effort. They become available as a kind of mental shortcut, which is exactly what an engagement ring shopper wants when standing in front of a jewelry counter trying to justify a purchase that costs two months of salary — another rule of thumb, incidentally, that N.W. Ayer invented.
The afterlife of four words
Frances Gerety died in 1999, the same year Advertising Age named her line the slogan of the century. She was 83. The obituaries described her as a pioneering woman in advertising and noted, almost as a footnote, that she had never married. De Beers, by then a global conglomerate, kept the slogan running. It still runs.
The diamond engagement ring, which did not exist as a near-universal custom before her campaign, is now worn by the majority of brides in the United States, Japan, China, and a growing list of other markets. Geologists will tell you that diamonds are not, technically, forever — under high enough temperature and pressure they convert back to graphite, and on long enough timescales even the stones in a setting are slowly losing carbon atoms. The line was always a small lie.
Gerety knew. She had written it as a closing argument, not a scientific claim. She went home to her small house in Philadelphia, fed her dogs, and went to sleep, having that morning convinced several million strangers to spend several months of income on a piece of carbon she would not, herself, ever wear.
A copywriter named Frances Gerety working at the Philadelphia advertising agency N.W. Ayer created the line A Diamond Is Forever for a client called De Beers, the South African mining cartel. The slogan would run on De Beers advertising for decades, and the campaign it anchored would invent, almost from scratch, the idea that an engagement ring should cost a man two months’ salary — a number that had no basis in tradition, etiquette, or jewelry industry practice.
The figure started smaller. In the early twentieth century, diamond engagement rings were relatively uncommon among American brides, and rings cost less than they would later.
By the 1980s, De Beers had pushed the American benchmark to two months. In Japan, where the company began advertising in the 1960s, it set the figure at three.
The slogan that ran for 75 years
Gerety worked at N.W. Ayer for her entire career. A Diamond Is Forever became one of the most recognized advertising slogans of the twentieth century. The line did two things at once. It implied that a diamond, like the marriage it symbolised, was eternal — and it discouraged resale, because a stone you would never part with did not need a secondary market that might reveal how little used diamonds were actually worth.
De Beers did not sell diamonds directly to consumers. It sold rough stones to a tightly controlled group of cutters and wholesalers, and it needed to keep demand high enough to absorb the supply coming out of mines in South Africa, Botswana, and later Russia. Advertising was the lever.
Inventing a tradition that had not existed
The two-months-salary rule was not handed down from a Victorian etiquette guide. It was tested in print ads through the 1970s and 1980s, raised from one month to two as inflation and rising incomes allowed, and reinforced through magazine spreads featuring couples whose ring size was implicitly tied to the groom’s professional success. The company eventually stopped suggesting specific salary multiples in U.S. advertising, but by then the figure had embedded itself in popular memory as if it had always been there.
The campaign worked because it tied a luxury purchase to a social fear. A man who spent less risked appearing cheap or uncommitted; a man who spent more signalled devotion. The metric was self-reinforcing because almost no one resold the ring afterward, so the market never had to absorb the secondhand stones that would have exposed the inflated retail markup.
Repeated messaging can convert a manufactured benchmark into a perceived custom, particularly when the purchase is rare, emotionally loaded, and hard to comparison-shop.
The Japan campaign of 1967
Japan was the harder case. Diamonds were largely absent from Japanese weddings before De Beers began its campaign. Engagement gifts followed a traditional custom called yuino, which involved exchanges of symbolic items between the two families. Brides did not typically wear rings. Diamonds, when they appeared at all, were associated with Western excess and were considered ostentatious.
De Beers worked with advertising agencies to change that. The campaign placed diamond rings on young Japanese women photographed in Western settings — skiing, sailing, driving sports cars — surrounded by Western boyfriends and husbands. The visual argument was that diamonds belonged to a modern, internationally mobile, economically successful Japan, and that a man who proposed without one was clinging to a prewar past.
The salary benchmark in Japanese ads was set at three months’ salary, higher than the American figure. Japanese household savings rates were high at the time, and the campaign calibrated the ask accordingly.
How fast the custom took
The numbers shifted faster than almost any comparable case in consumer history. When the campaign launched in the late 1960s, few Japanese brides received diamond engagement rings. Within a few years, the figure began climbing rapidly. By the early 1980s, the majority of Japanese brides were receiving diamond engagement rings. By the late 1990s, the practice had become widespread, and Japan had become the second-largest diamond market in the world after the United States.
Within roughly thirty years, a country with no diamond tradition had adopted one as if it were ancient. Older relatives at weddings began to assume their granddaughters would receive a stone. Wedding magazines printed guidance on ring selection alongside articles on traditional kimono. The yuino ceremony itself often absorbed the ring as one of its exchanged items, blending the new custom into the old form so seamlessly that the seam disappeared.
Why the persuasion worked
Repeated exposure to a single visual framing — a young couple, a small velvet box, a specific cut of stone — establishes the diamond as the default object in the scene. Once the default is set, alternatives feel like deliberate refusals rather than neutral choices.
Purchases tied to identity transitions — marriage, parenthood, graduation — are especially susceptible to manufactured tradition, because the buyer is also performing a social role for an audience of family and peers.
The Japanese campaign exploited that exactly. A bride showing the ring to her mother was not just displaying a stone; she was confirming that the marriage met a modern standard.
The royal accelerant
One outside event amplified the campaign more than any single ad. In 1981, Prince Charles proposed to Lady Diana Spencer with a 12-carat oval Ceylon sapphire surrounded by 14 diamonds — a ring that broke generations of royal tradition by being chosen from a commercial Garrard catalogue rather than commissioned bespoke. The wedding drew a global television audience, including a substantial viewership in Japan, where the broadcast aired with translation.
Diana’s ring was not a solitaire diamond, but the broader visual — a Western royal bride wearing a serious gemstone — fed directly into the framing De Beers had been building. Sales accelerated in both markets through the 1980s.
What the campaign is doing now
The structure has begun to wobble. Lab-grown diamonds, chemically identical to mined stones, now sell at substantially lower prices than natural equivalents, and younger buyers in the United States and East Asia have proved willing to choose them. De Beers spent decades insisting that synthetics were not real diamonds, then launched its own lab-grown brand called Lightbox, and has since pulled back.
In October 2025, the company launched a campaign called Desert Diamonds, its largest in a decade, aimed at re-establishing the cultural premium of natural stones. A separate rebrand of the De Beers jewelry line features the model Adwoa Aboah and a new Paris flagship, framing natural diamonds as heritage objects rather than commodity purchases.
Japan’s diamond market has softened since its peak, partly as marriage patterns have shifted. The three-months-salary rule is now treated by many younger couples as a vintage idea rather than a binding one. The custom is no longer growing. It is also not disappearing — the wedding ring section of any department store in Tokyo still displays solitaires under the same lighting used in the original campaign.
What Frances Gerety left behind
The slogan Gerety wrote had been printed in more languages than almost any other piece of commercial copy in history, and the salary multiples it anchored — two months in America, three in Japan — had reshaped how hundreds of millions of people thought about the moment of proposal.
The diamonds themselves were chemically the same carbon they had always been. The forever was the advertising.
During World War II, the United States War Production Board accused De Beers of hoarding industrial diamonds and putting Allied factories at risk to protect its monopoly. The cartel reportedly sat on a substantial stockpile of crushed bort and small industrial stones in London, refused to ship more than a fraction across the Atlantic, and priced Washington’s strategic stockpile prohibitively. American B-17 engines, machined to thousandths of an inch, depended on diamond-tipped dies and grinding wheels that could not be made any other way.
The accusation came from inside the Roosevelt administration, in memos that circulated between the Justice Department, the War Production Board, and the Office of Strategic Services. The charge was blunt: a private South African and British company was, in effect, rationing the United States war effort.
Why a tank factory needed diamonds
Industrial diamonds are not the gem-grade crystals in an engagement ring. They are dark, fractured, almost ugly. They are also the hardest known natural material, and in the 1940s nothing else could shape tungsten carbide tooling, drill jet-engine nozzles, or finish the bearing surfaces on a Wright Cyclone aero engine.
A single Sherman tank required diamond abrasives at dozens of stages of its manufacture. A Pratt and Whitney radial engine could not be built without diamond dies for drawing the fine tungsten wire used in its spark plugs. Multiply that by tens of thousands of aircraft and the math became urgent.
By the early 1940s, the United States consumed a substantial majority of the world’s industrial diamond supply. Almost all of it had to pass through one company.
The cartel in the middle
De Beers Consolidated Mines, founded by Cecil Rhodes in the late nineteenth century, controlled the diamond trade through a marketing arm called the Central Selling Organisation, run out of London by Sir Ernest Oppenheimer. Stones from South Africa, the Belgian Congo, Angola, and Sierra Leone flowed into one set of vaults and were released to the world in carefully metered quantities to keep prices firm.
Industrial diamonds were a smaller, less glamorous part of that business, but the same rules applied. The CSO decided what came out of the vault and at what price.
Washington wanted a war reserve of several million carats of industrial stones held on American soil. Oppenheimer’s organization reportedly offered to sell a fraction of that amount, and only on the condition that the stockpile not be drawn down in ways that disturbed the postwar market. The War Production Board considered the offer insulting.
The 1944 memo
Internal documents from the period reportedly accused De Beers of jeopardizing Allied war production. The cartel, the memos argued, was willing to risk Allied factories running short of grinding wheels rather than let a strategic stockpile sit in American hands where it might one day be sold off and crash the diamond price.
The Justice Department opened an antitrust investigation. De Beers, having no operations or executives on US soil, simply ignored the subpoenas. There was no one in America to serve.
Smugglers, OSS agents, and the Congo
The shortfall was real enough that the Office of Strategic Services, the wartime predecessor to the CIA, ran a covert operation into the Belgian Congo to find out where industrial diamonds were actually going. The Congo was then the largest source of industrial-grade stones in the world, mined at Forminière concessions whose output was funneled through the CSO in London.
OSS investigators concluded that significant volumes of Congolese diamonds were leaving Africa through Portuguese, Lebanese, and Belgian middlemen and ending up on the black market in neutral Tangier, from where some reached Germany. The Reich, cut off from any legal supply, needed diamonds for the same reason the Allies did: to machine engines, drill armor plate, and grind precision optics for tank sights and submarine periscopes.
How many carats reached Nazi Germany, and through whose hands, was never settled. The numbers in the OSS files run from a few hundred thousand carats per year to well over a million. What the agents could not establish was whether the leakage was tolerated by the cartel as the cost of doing business, or actively organized.
The stockpile that never quite filled
The Roosevelt administration eventually built up its strategic industrial diamond stockpile, but slowly and at prices set entirely by the CSO. Stones were shipped from London to New York in small lots, often by courier on Pan American flying boats, insured for sums that look modest now but were enormous in 1943 dollars.
By the time the reserve approached the level the War Production Board had originally demanded, the war in Europe was nearly over. American machinists had spent three years working with grinding wheels that wore out faster than they should have, using substitute abrasives like silicon carbide where they could, and rationing diamond dies between competing aircraft programs.
The Wright Aeronautical plant in Paterson, New Jersey, a major producer of radial aircraft engines, kept a locked room for diamond tools with a sign-out log that was reviewed weekly by management.
The lawsuit that went nowhere
After the war, the Justice Department filed a formal antitrust suit against De Beers, charging the company with conspiring to fix the price of industrial diamonds and with restricting supply during wartime. The case dragged on for years. De Beers continued to operate entirely outside US jurisdiction, refused to appear, and the suit was eventually dropped as legally unenforceable.
The practical consequence was that for the rest of the twentieth century, no senior De Beers executive could safely set foot in the United States without risking arrest on the open indictment. Company officials negotiated American sales through intermediaries and held their meetings in London, Lucerne, and Johannesburg.
The synthetic answer
The wartime shortage convinced the US government that depending on a single foreign cartel for a strategic material was unacceptable. Before American entry into World War II, the Carnegie Institution had begun experiments on making diamonds from graphite under pressure. The work was classified and underfunded, but it never stopped.
In the mid-1950s, a team at General Electric’s research laboratory in Schenectady, led by Tracy Hall, finally succeeded. Using a belt press of Hall’s own design, they squeezed graphite at extreme pressure and temperature and produced small, gritty, unmistakable industrial diamonds.
Hall’s compensation for the breakthrough became a point of controversy. The technology, patented and licensed under tight controls, eventually turned synthetic industrial diamond into a commodity. Today, the vast majority of industrial diamonds used worldwide are synthetic, made in presses descended from Hall’s, and the leverage the wartime cartel once held over American manufacturing simply evaporated.
What the memo really revealed
The wartime accusation was extraordinary not because it was novel but because it was made in writing, by a US government agency, against a private foreign company in the middle of a war. The War Production Board normally spoke the language of tonnages and delivery schedules, not the language of sabotage.
The choice of words mattered. To say that De Beers was jeopardizing Allied war production was to put the cartel in the same rhetorical category as a strike, a U-boat, or an act of espionage. The memo did not lead to prosecution, indictment, or any seizure of assets. It led to a stockpile slowly accumulated at the cartel’s preferred price and, in the longer run, to a Schenectady press that made the whole problem disappear.
For a brief period in the 1940s, a single London office could decide how quickly the United States built its bombers. The men who ran the War Production Board did not forget it, and neither did the chemists at General Electric.
The diamonds in the Wright engine plant in Paterson are long gone, ground down decades ago into the swarf of finished crankshafts. The memos sit in the National Archives. The synthetic stones that replaced the cartel’s hoard are made by the kilogram in industrial parks from Ohio to Henan, and they cost a few dollars a carat, sold by the bucket to anyone who needs to cut steel.
A modelling study published in Communications Earth & Environment in June 2025 found that the West Antarctic Ice Sheet could begin an irreversible collapse at ocean temperatures between zero and 0.25°C above current levels — meaning the threshold may have already been reached
Once the collapse begins, the authors argue, it would be self-sustaining: not a process that could be halted by subsequent emissions reductions, but one that would continue until the ice sheet had contributed roughly four metres to global sea levels. That contribution would unfold over centuries to millennia. The study is one modelling paper, not a settled consensus, but the threshold it identifies is lower than many prior estimates, and the mechanism it describes is worth examining closely.
The authors are David Chandler, Petra Langebroek, Ronja Reese, Torsten Albrecht, Julius Garbe, and Ricarda Winkelmann, working across the Potsdam Institute for Climate Impact Research, the Norwegian research centre NORCE, and Northumbria University. To examine how the ice sheet has responded to past conditions, they ran model simulations extending back 800,000 years, giving the analysis a long baseline of Antarctic ice sheet behaviour against which to calibrate the projections.
What the threshold means
The 0.25°C figure refers to ocean warming at depth around West Antarctica, not to global average surface temperature. The distinction matters. Ocean temperatures in the Amundsen Sea, which washes against the base of the West Antarctic glaciers, have already been rising as warmer Circumpolar Deep Water intrudes further onto the continental shelf. The study does not claim that threshold has been crossed; it identifies where, in the model, collapse becomes self-sustaining.
The mechanism at the centre of the analysis is marine ice sheet instability. The West Antarctic Ice Sheet sits largely on bedrock below sea level. Its glaciers are held in place partly by ice shelves, floating extensions of the sheet that buttress the flow of ice toward the ocean. As warm water undercuts those shelves, they thin. As the grounding line, where the glacier meets the ocean floor, retreats into deeper water, the geometry of the ice sheet becomes less stable. In this configuration, retreat can accelerate under its own weight without requiring additional external warming to continue.
This is the self-sustaining character the paper describes. Beyond the 0.25°C threshold in the model, the process continues even if ocean temperatures were to stop rising. The four metres of sea-level rise is not a peak that would be reached and then reversed; it is the new equilibrium state the ice sheet would settle toward over the following centuries and millennia.
What the paper does not show
This is one modelling study, not settled consensus. The result should be taken seriously, but it should not be read as the final word on the timeline, the precise threshold, or the certainty of collapse.
Modelling the West Antarctic Ice Sheet involves choices about ice physics, ocean forcing, and bedrock properties that different research groups represent differently. Other recent work has reached varying conclusions about how close the system currently sits to a tipping point, and the question of whether the ice sheet has already been destabilised is actively debated in the literature. A 2023 paper from a separate group concluded the sheet had not yet been pushed past tipping, while noting the path toward it was concerning.
The 800,000-year baseline the team used is a strength of the analysis, providing a longer view of how the ice sheet has behaved under past climate states than most studies can offer. But extrapolating from past behaviour to future response under conditions that may be outside the range of the historical record carries its own limitations, and the authors acknowledge these.
The asymmetry of the timescales
One detail in the paper that the coverage has noted is the asymmetry between the timescale of destabilisation and the timescale of ice sheet growth. It takes tens of thousands of years for a large ice sheet to accumulate. The conditions that could initiate collapse can be reached in decades. The four metres of sea-level rise would then play out over centuries. That sequence has a particular character: a fast trigger, a slow-moving consequence, and a very long tail.
Four metres of sea-level rise distributed over centuries is not an outcome that falls within ordinary planning horizons. It is an outcome that would affect coastlines and populations far beyond any current infrastructure’s design life. The paper frames the next few years as a period in which the trajectory of deep ocean warming around Antarctica will become clearer, and in which emissions choices will continue to influence where the system ends up relative to the threshold the model identifies.
What to watch
The Amundsen Sea embayment, where Thwaites and Pine Island glaciers are already showing significant grounding-line retreat, is the region the paper’s concerns centre on most directly. Ongoing observational work on those glaciers, including the International Thwaites Glacier Collaboration’s field campaigns, will provide ground-truth data against which modelling results like these can be tested.
Whether observed ocean temperatures at depth around West Antarctica are approaching the 0.25°C increment the study identifies, and how quickly, is a question the oceanographic record will continue to answer over the next several years.
For the first forty years of human spaceflight, getting into space required being a professional astronaut or cosmonaut. The selection processes were intensely competitive, the training programmes took years, the candidates were chosen from elite military pilot or scientific backgrounds, and the small number of people who eventually made it through the filtering and onto a launch vehicle were essentially all employees of the few national space agencies that operated launch programmes. From 1961 through 2001, approximately 400 individuals went to space, every one of them a professional. The first paying civilian, the American businessman Dennis Tito, finally reached the International Space Station in April 2001 by purchasing a seat on a Russian Soyuz for approximately $20 million. Six more spaceflight participants followed over the next eight years, all via the same Russian-operated route. Then the door closed. From 2009 to 2021, no private citizen reached space at all. The institutional pipeline that had briefly opened during the Russian post-Soviet financial squeeze closed again as the ISS partnership stabilised.
According to a detailed industry flight log of every commercial space tourism mission to date, the reopening of that door in 2021 was not gradual but discontinuous. Within a single ten-week period — Richard Branson on Virgin Galactic’s VSS Unity on 11 July 2021, Jeff Bezos on Blue Origin’s New Shepard on 20 July 2021, and Jared Isaacman’s all-civilian Inspiration4 mission on SpaceX’s Crew Dragon in September 2021 — three different commercial providers began operating crewed flights for paying customers. The civilian-to-space pipeline that had been closed for twelve years suddenly had three independent operational paths. The cumulative number of private civilians flown to space, which had been seven for over a decade, began to climb rapidly. By the end of 2022 it had passed twenty. By the end of 2024 it had passed eighty. By early 2026 the figure had reached approximately 120, and despite Blue Origin’s January 2026 decision to pause New Shepard flights to focus on lunar missions, the underlying trajectory has continued.
The arithmetic of the shift
The total number of human beings who have left Earth’s atmosphere across the entire history of spaceflight is, by current estimates, approximately 700. NASA has contributed roughly 360 of these. The Soviet and subsequent Russian programmes have contributed approximately 135. The European Space Agency, JAXA in Japan, the Canadian Space Agency, the Chinese taikonaut programme, and several smaller national programmes account for most of the rest. The 120 commercial civilians who have flown since 2021 represent approximately 17 percent of this cumulative total — roughly one in six of every person who has ever crossed into space, all of them in the past five years, almost none of them with the professional training that defined every previous generation of spacefarer.
The rate dynamics are the more striking part. Per CBS News’s coverage of the broader commercial spaceflight phenomenon, the major national astronaut corps have been operating at roughly stable launch cadences for the past decade — NASA sends approximately 8 to 12 astronauts to the ISS per year, Roscosmos sends roughly 4 to 6 cosmonauts, the Chinese taikonaut programme launches a similar number to its Tiangong space station, and ESA contributes a handful through its partnership arrangements. The total professional astronaut launch rate sits at roughly 25 to 30 humans per year, and has been at this level for most of the post-Shuttle era. The commercial civilian launch rate, by contrast, was effectively zero from 2009 to 2021 and has been climbing rapidly since. Blue Origin’s New Shepard alone flew approximately 30 civilians across multiple missions in 2024-2025. Virgin Galactic flew another seven commercial missions before pausing operations in 2024 for an upgraded vehicle. SpaceX flew the Polaris Dawn mission (four civilians) in September 2024 and continues operating crewed Crew Dragon flights for paying customers. Multiple Axiom Space missions have carried paying civilians to the ISS. The total commercial civilian launch rate for 2024-2025 substantially exceeded the professional astronaut rate.
What civilian flights actually involve
The two halves of the commercial spaceflight industry — suborbital and orbital — are different enough that they are essentially separate products. Suborbital flights, operated by Blue Origin (New Shepard) and Virgin Galactic, briefly cross the boundary of space (the internationally recognised Kármán line at 100 kilometres altitude, or the US-recognised 80 kilometres) and return immediately. The full flight, from launch to landing, typically lasts about 10 to 12 minutes. Passengers experience approximately 3 to 6 minutes of weightlessness at apogee, see the curvature of Earth and the blackness of space through windows, and then re-enter and land. Ticket prices range from approximately $200,000 to $600,000 depending on operator. As reported by Mexico Business News’s industry overview, suborbital flights account for the substantial majority of commercial civilian spaceflights to date by passenger count.
Orbital flights are an entirely different proposition. SpaceX’s Crew Dragon and Axiom Space’s missions to the International Space Station place passengers into sustained low Earth orbit, with mission durations typically ranging from several days to several weeks. Ticket prices for orbital missions start at approximately $55 million and can exceed $200 million for chartered Crew Dragon flights. The 2024 Polaris Dawn mission, funded by Jared Isaacman and operated by SpaceX, reached an altitude of 1,400 kilometres — the highest crewed Earth orbit since the Apollo programme — and included the first commercial spacewalk in history. The orbital civilian flights are substantially rarer than suborbital ones (fewer than 20 total individuals to date) but represent the more technologically ambitious frontier of the commercial spaceflight industry.
What the trend means
As covered by a March 2026 Yahoo News analysis of Blue Origin’s decision to pause New Shepard operations, the commercial spaceflight industry is now mature enough that operational decisions by individual providers (Virgin Galactic pausing for vehicle upgrades, Blue Origin pausing to redirect engineering resources to lunar missions) substantially affect industry-wide launch cadence but do not threaten the basic existence of the category. Multiple additional providers are at various stages of operational development: Vast’s Haven-1, a single-module commercial space station, is targeted for launch on a SpaceX Falcon 9 in May 2026, with the company aiming to become the world’s first standalone commercial space station operator; Sierra Space’s Dream Chaser spaceplane is in late-stage development; and Axiom Space’s commercial space station is intended to begin operations and eventually replace the ISS by 2030. Virgin Galactic’s Delta-class vehicle, designed for monthly commercial flights, is targeted to enter operations in late 2026.
The structural shift that the cumulative 120 commercial civilians represent is not yet visible at the level of cultural recognition. Most people, asked how many private citizens have been to space, would probably guess a number an order of magnitude lower. The transition from spaceflight as an exclusively professional activity to spaceflight as a commercial product purchasable by paying customers has, by every available indication, now happened — quietly, gradually, and faster than most observers anticipated. The next question is whether the trajectory continues. If the rate-acceleration of the past five years extends through the rest of the decade, the cumulative number of private civilians in space will, by 2030, substantially exceed the cumulative number of professional astronauts who flew across the entire 60-year history of spaceflight before commercial operations began. Whether that crossing point gets noticed at the time, or whether it gets registered only in retrospect like most of the structural shifts of the past several years, is a separate question. The numbers themselves are no longer particularly contestable.
The deepest hole humans have ever dug, the Kola Superdeep Borehole on the Kola Peninsula in Russia, reached approximately 12 kilometres before the heat, pressure, and engineering challenges of drilling overwhelmed the equipment. Earth’s mantle begins at approximately 35 kilometres depth and continues to approximately 2,890 kilometres — 1,800 miles — where it meets the boundary of the molten outer core. Every layer beneath the upper crust of Earth is, in practical terms, inaccessible to direct observation. Everything humans know about the interior of the planet has been inferred from seismic waves passing through it: their travel times, their reflections, their refractions, the patterns of speed and direction by which they emerge at the surface after earthquakes generate them on the other side of the globe. The most striking thing humans have learned about the planet’s interior from these inferences, over the past several decades, is that the lowest layer of the mantle is not uniform. It contains two enormous, continent-spanning, distinct structures.
According to a comprehensive reference summary of LLSVPs in the geophysical literature, the two structures are formally known as Large Low-Shear-Velocity Provinces (LLSVPs), a name derived from the technical observation that distinguishes them — they slow down seismic shear waves by approximately 1 to 3 percent relative to the surrounding mantle. They were discovered in the late 20th century as global seismic tomography improved enough to resolve them. The African LLSVP, sitting beneath Africa and the eastern Atlantic, was eventually named Tuzo in honour of the Canadian geologist John Tuzo Wilson, one of the founding figures of plate tectonics. The Pacific LLSVP, sitting beneath the central and western Pacific Ocean, was named Jason in honour of the American geophysicist W. Jason Morgan, who developed the modern theory of mantle plumes. The names were proposed in 2011 by the geologist Kevin Burke. The two structures together occupy approximately 8 percent of the volume of Earth’s mantle, or roughly 6 percent of the total volume of the planet.
How big they actually are
The Pacific LLSVP, Jason, extends approximately 3,000 kilometres laterally — nearly 1,900 miles across, comparable to the width of the contiguous United States. The African LLSVP, Tuzo, is similarly continental in scale, extending across much of the African plate and into the southern Atlantic. Both structures rise vertically from the core-mantle boundary by up to approximately 1,000 kilometres — taller than the height of the Earth’s atmosphere by a factor of ten. Each is, in absolute terms, substantially larger than any feature visible on the planet’s surface. The Himalayas, if dropped into Tuzo or Jason, would be one of the smaller features within the structure. The entire continent of Australia, if shrunk down to fit, would occupy a modest fraction of either LLSVP. The structures are not visible, not directly accessible, not detectable except via seismic inference, and not part of the standard educational treatment of Earth’s interior — but they are, in raw scale, among the largest individual structures the species has ever identified inside any planetary body.
As reported by a 2018 paper in Geoscience Frontiers by the geochemist Yaoling Niu on the origin of LLSVPs, the two structures are not symmetrically distributed around the planet. They are antipodal — sitting on roughly opposite sides of Earth from each other — and equatorial, with their combined centre of mass aligned with the planet’s rotation axis. This geometric arrangement is one of the proposed reasons for their long-term stability. A pair of large mass anomalies positioned this way is, dynamically, in a configuration that resists lateral migration during the planet’s rotation. Whatever Tuzo and Jason are, they have been sitting essentially where they currently sit for an extraordinarily long time.
How long they have been there
The temporal stability of the LLSVPs is, by paleogeological standards, remarkable. The continents on Earth’s surface have moved substantially during the past several hundred million years — Pangaea broke apart approximately 200 million years ago, the Atlantic Ocean has been opening since, India collided with Asia approximately 50 million years ago, and the basic configuration of the surface looked entirely different in geological deep time. The LLSVPs, in contrast, appear to have stayed put. The evidence comes from a clever geological argument. Hotspots — the volcanic features at the surface where mantle plumes break through, such as Hawaii, Iceland, the Canary Islands, and Réunion — appear to originate predominantly at the edges of the LLSVPs, in regions geologists now call Plume Generation Zones. When ancient hotspot tracks are reconstructed and mapped back through 300 million years of plate motion, more than 90 percent of them line up with the current locations of the LLSVP margins. Some reconstructions extend the pattern back to 540 million years ago, into the early Cambrian. This suggests Tuzo and Jason have been holding their shape, and their positions, since before the appearance of complex life on land.
What they actually are
What Tuzo and Jason are made of, and how they originally formed, is one of the major unresolved questions in deep-Earth geophysics. Per a 2016 review in Nature Geoscience by Garnero, McNamara, and Shim on continent-sized anomalous zones in the deep mantle, several distinct hypotheses are currently being investigated. The thermal interpretation holds that LLSVPs are simply zones of unusually hot mantle, where the slower shear wave velocities reflect higher temperature. The chemical interpretation, supported by the difficulty of explaining the LLSVPs’ apparent density excess with temperature alone, holds that they are compositionally distinct — possibly enriched in iron, possibly containing material from subducted oceanic crust accumulated over hundreds of millions of years, possibly remnants of a primordial layer that survived from early Earth differentiation.
As covered in a Daily Galaxy summary of a recent hypothesis on LLSVP origin from early-Earth core-mantle material exchange, one increasingly explored hypothesis is that LLSVPs may date back to the very early period of Earth’s formation, approximately 4 billion years ago, when the entire planet was a global magma ocean and material was exchanging freely between what would eventually become the core and what would eventually become the mantle. The 2025-2026 simulations supporting this interpretation suggest that material contaminated by core composition could have accumulated in two stable, antipodal locations during the cooling of the early magma ocean — eventually crystallising into the dense, hot, chemically distinct structures that are still sitting in those locations 4 billion years later. Whether this interpretation, the subducted-crust interpretation, the primordial-layer interpretation, or some combination turns out to be correct will require more seismic data, more mineral physics experiments at the relevant pressures and temperatures, and probably the kind of multi-decade research programme that deep-Earth geophysics has historically required.
What is no longer in doubt is that the structures exist, that they are extraordinarily large, that they have been stable for hundreds of millions of years, and that they appear to control where most of the planet’s hotspot volcanism happens at the surface. The Hawaiian Islands are erupting where they are because Jason’s edge is underneath. The Canary Islands erupted in 2021 because Tuzo’s edge is underneath. The largest geological structures in human experience are, in a literal sense, downstream effects of much larger structures sitting at the base of the mantle, which no human will ever see and which the species nonetheless now knows are there.
When Suni Williams and Butch Wilmore packed for their trip to the International Space Station in early June 2024, they packed for approximately a week. The mission profile was eight to ten days. The clothes they brought, the personal items they brought, the level of mental preparation they brought were all calibrated to a trip about the length of a tropical vacation. Two hundred and eighty-six days later — having lived aboard the ISS for the better part of a year, having become full members of two consecutive Expedition crews, having watched their original spacecraft return to Earth without them in September because NASA had concluded it was no longer safe to ride home in — they finally landed in the Gulf of Mexico aboard a SpaceX capsule on 18 March 2025. The eight-day mission had, by then, become the longest single accidental extension of a human spaceflight in NASA history, and the most public engineering crisis the Boeing Commercial Crew Program had yet encountered.
According to Space.com’s coverage of the Starliner thruster crisis, the immediate problems began as Starliner approached the ISS for docking on 6 June 2024. Five of the capsule’s 28 maneuvering thrusters, mounted on the service module, began misfiring or shutting down entirely. Helium leaks were detected in the propulsion system manifolds. The docking was eventually completed, but the underlying questions about the vehicle’s ability to safely undock from the station and execute the precise series of deorbit burns required to bring the astronauts home became, in subsequent weeks, increasingly serious. The original plan had assumed Starliner would carry Williams and Wilmore back to Earth within ten days of arrival. By late July 2024, NASA and Boeing engineers were still trying to determine whether the propulsion problems could be safely characterised, much less corrected. The astronauts remained aboard the ISS while ground engineers ran simulations.
The decision
The formal decision came on 24 August 2024. Per NASA’s official announcement of the uncrewed-return decision, the agency concluded that bringing Williams and Wilmore home aboard Starliner posed risks it was not willing to accept. The specific failure mode that worried engineers most concerned Teflon seals inside the thrusters that appeared to be degrading and bulging when the thrusters fired at high temperatures — a problem that could not be fully characterised because the service module containing the affected thrusters was scheduled to burn up during atmospheric reentry, eliminating the possibility of post-flight inspection. The agency’s administrator at the time, Bill Nelson, summarised the rationale: “Spaceflight is risky, even at its safest and most routine. A test flight, by nature, is neither safe, nor routine.” Starliner would return to Earth uncrewed. Williams and Wilmore would be folded into the ISS’s regular crew rotation and would eventually come home aboard a SpaceX vehicle.
Starliner undocked from the ISS on 6 September 2024, executed its deorbit burn successfully, and landed at White Sands, New Mexico — without crew, without serious incident, and without resolving any of the underlying engineering questions about whether it could have safely brought Williams and Wilmore home if it had been required to. Three weeks later, on 28 September 2024, a SpaceX Crew Dragon capsule launched to the ISS carrying NASA astronaut Nick Hague and Russian cosmonaut Aleksandr Gorbunov. Two of the four seats were left intentionally empty, reserved for Williams and Wilmore’s eventual return. That return would not happen for another six months.
What the 286 days actually involved
The “stranded” framing that dominated media coverage of the situation became, over the subsequent months, a source of mild frustration for the astronauts themselves. Williams and Wilmore were not stranded in the literal sense. They were absorbed into the ISS’s standard crew rotation as members of Expedition 71 and then Expedition 72. They conducted scientific research. They performed maintenance on station systems. Williams became ISS commander in September 2024 and completed multiple spacewalks during her extended mission, including one that pushed her cumulative spacewalk time to a record for a female astronaut. Both Williams and Wilmore have repeatedly described their extended stay in terms that emphasise their professional engagement with the work rather than any sense of isolation or distress.
Williams’s total accumulated spaceflight time across her career, by the time of her March 2025 return, reached 608 days — the fourth-highest cumulative total of any NASA astronaut and the highest of any NASA woman. The 286-day mission itself sits comfortably within the range of routine modern ISS expeditions; Scott Kelly’s 340-day mission in 2015-2016 was longer, and Frank Rubio’s 371-day mission in 2022-2023 was longer still. The physiological recovery required upon return was substantial but within standard parameters for long-duration ISS missions. Bone density loss, muscle atrophy, cardiovascular deconditioning, and the cluster of vision-related changes documented in long-duration spaceflight all applied to both astronauts, but the rehabilitation protocols were well-established and the recovery proceeded along expected lines.
What the mission means for Boeing
The Starliner programme, by every available measure, is in substantial trouble. As reported by CNBC’s coverage of the March 2025 return, Boeing’s $4.2 billion Commercial Crew Program contract with NASA — signed in 2014, alongside a smaller $2.6 billion contract awarded to SpaceX — has now produced exactly one crewed flight that failed to return its crew aboard its own vehicle, after more than a decade of development delays, two uncrewed test flights (one of which also failed to reach the ISS), and multiple billion-dollar cost overruns absorbed by Boeing itself. SpaceX’s competing Crew Dragon, by contrast, has completed eleven operational crewed missions to the ISS since its first crewed flight in May 2020, has carried more than fifty astronauts safely to and from the station, and has now also rescued the two astronauts that Boeing’s vehicle was unable to return.
Whether Starliner ever flies humans again remains, as of mid-2026, an open question. As documented in NASA’s official return-announcement statement, the agency has not committed to a specific date for the next Starliner mission, crewed or uncrewed. The engineering questions about the service-module thrusters remain partially unresolved because the affected hardware no longer exists. Boeing has indicated that it intends to address the propulsion issues in subsequent vehicles and that it remains committed to the Commercial Crew Program. NASA, for its part, has indicated that it still wants a second commercial crew provider as a backup to SpaceX. Whether the second provider continues to be Boeing, and whether the next Starliner flight occurs in 2026, 2027, or later, will depend on technical, financial, and political decisions that the agency has not yet made publicly. The 286 days that Williams and Wilmore spent in orbit after their eight-day mission ended are, in this respect, a piece of operational evidence whose institutional consequences are still in the process of being worked out.
The record sits at the top of every list of human spaceflight endurance achievements, has been there since 1995, and is currently held by a man who has been dead for three years. Valeri Polyakov, born in Tula, Russia in 1942, trained as a medical doctor specialising in space medicine before joining the Soviet cosmonaut corps in 1972, and spent the better part of his subsequent career attempting to answer a single question with his own body: whether a human being could survive, biologically and psychologically, the round-trip duration of a flight to Mars. His first flight, in 1988-1989, lasted 240 days — at the time among the longest space missions ever attempted. His second flight, launched on 8 January 1994 aboard Soyuz TM-18, was specifically planned to extend beyond the projected duration of a Mars mission. He stayed in space for 437 days. He returned on 22 March 1995. No human being has stayed in space continuously for longer since.
According to Astronomy.com’s 2022 obituary of Polyakov following his death at age 80, the specific scientific purpose of the 437-day mission was Mars-mission validation. The transit time to Mars on a standard low-energy trajectory is approximately 7 to 9 months in each direction; combined with a surface stay of approximately 1 year (the typical “long-stay” mission profile), the total mission duration for a crewed Mars expedition would be approximately 14 to 18 months. Polyakov’s 437 days — slightly over 14 and a half months — covers the round-trip duration of the shortest plausible Mars mission profile. The Soviet (later Russian) space medicine community had been planning a Mars mission, in some form, since the 1960s; Polyakov’s flight was the medical proof-of-concept that the human body could endure the required time in microgravity.
What the mission actually required
Polyakov’s working environment for those 437 days was the Mir space station — a Soviet-era orbital outpost launched in 1986, roughly the size of a school bus, with a total internal working volume of approximately 350 cubic metres distributed across multiple modules connected by narrow passageways. By 1994, Mir was already eight years old and showing signs of wear. The cooling system was unreliable. The toilet had recurring problems. The communications systems were limited by the standards even of the time. Polyakov’s living conditions were substantially harsher than the conditions available to modern astronauts on the International Space Station, which has approximately three times the pressurised volume of Mir and substantially more comfortable accommodations across essentially every dimension. Polyakov adapted by establishing a strict daily routine: approximately two hours of mandatory exercise (a mix of treadmill running and resistance training), scientific work, medical self-experimentation, communications with ground controllers, and disciplined sleep schedules.
As reported by RocketSTEM’s coverage of the mission, Polyakov’s medical training proved decisive. He was, in essential respects, both the experimental subject and the experimenter. He documented in detail the physiological changes his body underwent over the 14-and-a-half months: bone density loss in weight-bearing skeletal regions at approximately 1 to 2 percent per month, muscle atrophy despite his exercise protocol, cardiovascular changes including some loss of cardiac muscle mass, and the cluster of vision-related changes that have since been named Spaceflight-Associated Neuro-ocular Syndrome. He tested countermeasures against these changes, refined the exercise protocols in real time, and produced the medical baseline against which all subsequent long-duration spaceflight has been measured.
The landing
The moment that became the iconic image of the mission was not the launch, not any specific event during the 14 months in orbit, but the landing itself. As described in Britannica’s biographical entry on Polyakov, when the Soyuz TM-20 capsule containing Polyakov touched down on the steppes of Kazakhstan on 22 March 1995, ground crews approached with stretchers, fully expecting that a man who had spent 14.5 months in microgravity would be unable to support his own weight. Polyakov refused the stretcher. He climbed out of the capsule on his own, walked the short distance to a nearby lawn chair, and sat down. The gesture was deliberate. He had spent the entire mission, and arguably his entire career, attempting to demonstrate that long-duration spaceflight did not necessarily produce a human being too physiologically broken to function on arrival. Walking himself from the capsule to the chair was the visible answer.
His first words to the assembled press, in Russian, translated to the equivalent of: “We can fly to Mars.” The statement was not a metaphor or an aspirational quote. It was a clinical assessment from a doctor who had just personally completed the experiment.
Why the record still stands
Per Space.com’s history of ultra-long-duration spaceflight, no human being has stayed in space continuously for as long as Polyakov did in any of the 31 years since his return. NASA’s Scott Kelly came within approximately three months, completing 340 days aboard the ISS in 2015-2016 as part of the agency’s “Year in Space” study. NASA’s Christina Koch reached 328 days in 2019-2020. NASA astronaut Frank Rubio set the American single-mission record at 371 days during an unplanned mission extension in 2022-2023. The current cumulative space-time record is held by the Russian cosmonaut Oleg Kononenko, who has accumulated approximately 1,110 days across five separate missions — but no individual mission of his, or any other cosmonaut’s, has exceeded Polyakov’s 437 consecutive days.
The reason the record has not been broken is not that humans cannot endure longer missions — Polyakov demonstrated that they can. It is that the modern crewed-spaceflight programmes have, for various operational, political, and risk-management reasons, settled on six-month rotations as the standard ISS expedition duration, with occasional yearlong missions conducted as specific scientific experiments. The radiation exposure accumulated during longer missions, in low Earth orbit, is substantial; over the full lifetime of a cosmonaut or astronaut, multiple yearlong missions are generally not considered medically advisable. Polyakov accepted this risk in 1994 because the mission was designed to deliver a specific scientific result that no shorter flight could provide. The result was delivered. The result has not been substantially improved upon since.
The peculiar feature of the current moment is that Polyakov’s mission was conducted to validate human Mars exploration, and 31 years later, no human being has yet flown to Mars. The medical baseline is in place. The proof of biological feasibility is on the books. The next step — actually sending a crew to Mars — has been planned, replanned, postponed, and refigured by multiple space agencies across three decades, with the leading current candidate (SpaceX’s Starship-based architecture) targeting the early 2030s. Whether the eventual crew on the first Mars mission will benefit directly from the data Polyakov collected, or whether the record-holder will quietly remain the holder of a piece of human endurance that was waiting for a use case that never materialised, is one of the open questions of the next decade. The 437 days are sitting on a shelf. The doctor who walked himself off the Soyuz in March 1995 is no longer alive to see whether they get used.
GPS is usually described as a satellite navigation system, but the quieter truth is that it is also a clock system. The blue dot on a phone depends on satellites broadcasting time and position so precisely that small errors in time become large errors on the ground.
The broad claim is right: without relativistic corrections, GPS would drift by roughly 10 kilometres a day. The wording needs one adjustment. GPS is built around a nominal 24-satellite constellation, but the U.S. Space Force normally flies more than 24 satellites. GPS.gov says its space segment listed 31 operational satellites as of July 3, 2023, while Space Systems Command said the constellation reached 32 active satellites after GPS III-8, also known as SV-10, was delivered to orbit in April 2026.
Each GPS satellite contains multiple atomic clocks, according to GPS.gov. Those clocks provide the precise timing data encoded into GPS signals, allowing receivers to calculate position by comparing how long signals from different satellites took to arrive.
Why navigation depends on time
A GPS receiver does not know where it is by recognising a place. It works by measuring distance from several satellites. Each satellite broadcasts a time-stamped signal. The receiver compares the time the signal was sent with the time it arrived, then turns that delay into distance.
That calculation depends on the speed of light. A timing error of one microsecond is already about 300 metres of distance error. A larger timing drift would not stay hidden inside the mathematics. It would become a wrong position.
GPS.gov describes the space segment as a nominal constellation of 24 operating satellites that transmit one-way signals giving satellite position and time. The control segment maintains satellite orbits, uploads navigation data, and adjusts satellite clocks.
The satellites do not keep Earth time naturally
The reason relativity matters is that GPS clocks are not sitting beside us. They are moving quickly in medium Earth orbit, and they are farther from Earth’s mass than clocks on the surface.
Both facts change the rate at which time passes.
According to the U.S. National Institute of Standards and Technology, special relativity makes GPS satellite clocks fall behind Earth clocks by about 7 microseconds per day because the satellites are moving quickly. General relativity works in the opposite direction: because the satellites are in weaker gravity than clocks on Earth, their clocks run faster by about 45 microseconds per day.
Put together, the satellite clocks run about 38 microseconds per day faster than comparable clocks on Earth. That is not a large number in ordinary life. It is large in a system where radio signals travel at light speed and where the receiver is solving for position from timing differences.
Where the 10-kilometre figure comes from
A drift of 38 microseconds per day corresponds to roughly 11 kilometres of light-travel distance. This is why the common shorthand says that without relativity, GPS would be wrong by about 10 kilometres a day.
That does not mean every receiver would suddenly jump exactly 10 kilometres after midnight. GPS error modelling is more complicated than that, because receivers solve for multiple satellite ranges and clock bias at once. But the order of magnitude is right: an uncorrected relativistic clock drift would grow quickly enough to make normal navigation unusable.
Neil Ashby’s widely cited paper, “Relativity in the Global Positioning System,” published in Living Reviews in Relativity, states the point directly: GPS uses accurate, stable clocks in satellites and on the ground, and the gravitational and motional frequency shifts are large enough that the system would not work without accounting for relativistic effects.
The correction is built into the system
The useful part of the story is not that GPS somehow proves relativity every time someone opens a map app. The better reading is more practical: relativity is part of the engineering model.
GPS satellites are not launched with clocks that are simply left to run as though they were on Earth. The system accounts for the predictable offset between orbit and the ground, and the control segment continues to monitor and adjust the clocks as part of normal operation. GPS.gov describes that control segment as responsible for tracking the satellites, uploading navigation data, maintaining constellation health, and adjusting satellite clocks.
This is the cleaner version of the claim: GPS depends on atomic clocks aboard satellites, and those clocks must be corrected for the effects described by special and general relativity. Without that correction, the accumulated timing error would translate into navigation errors on the scale of kilometres per day.
A small daily correction behind an ordinary blue dot
There is a tendency to turn this into a clever fact about Einstein hiding inside a phone. That is not wrong, but it can make the system sound more magical than it is.
The more interesting point is that GPS works because physics, engineering, ground monitoring, satellite clocks, orbital modelling, and receiver mathematics all have to agree closely enough for a tiny timing signal to become a useful location.
Relativity is not a decorative explanation added after the fact. It is one of the corrections that lets the system function at all.
Enceladus is small, only about 500 kilometres across, a moon you could lose among Saturn’s dozens. It is also one of the most interesting places in the solar system to ask whether life could exist beyond Earth. From cracks near its south pole it is constantly spraying water vapour and ice grains into space, drawn from a salty ocean hidden beneath its frozen shell, and the chemistry of that spray has made a real case for the moon being habitable.
Habitable, it is worth saying at the outset, is not the same as inhabited. Nothing living has been found there. What Enceladus has is the conditions.
A moon that leaks
NASA’s Cassini spacecraft discovered the plumes in 2005, jets of vapour and frozen droplets erupting from four warm fractures, nicknamed the tiger stripes, across the moon’s southern terrain. The material feeds one of Saturn’s faint rings and, more usefully, betrays what lies underneath: a global ocean of liquid salt water wrapped around the moon’s rocky core, kept from freezing beneath kilometres of ice.
That arrangement handed scientists an unusual gift. An ocean world that vents its own ocean into space is a world you can sample without landing, and Cassini did exactly that, flying repeatedly through the plume to taste what came out.
The ocean has the ingredients
What the spacecraft found, over a series of passes, reads like a checklist for habitability.
There was salt, and silica, and a range of organic molecules. In 2017, the Cassini team reported molecular hydrogen in the plume, which on Earth is produced where hot rock meets water. Its presence is strong evidence of hydrothermal vents on the ocean floor, the same kind of warm, mineral-rich setting that supports thriving communities of life around Earth’s deep-sea vents, and a potential source of chemical energy.
Then, in 2023, came the ingredient that had been missing. Analysis of Enceladus ice grains revealed phosphates, the first time phosphorus had been detected in an ocean beyond Earth. Phosphorus is one of the elements life as we know it cannot do without, and on Enceladus it appears to be present at concentrations at least a hundred times higher than in Earth’s seawater. Water, energy, and the chemistry of life were now all accounted for.
Warm, and possibly old
The remaining question is time. A pond with the right ingredients is not enough if it freezes solid every few thousand years. For life to have a chance, the ocean would need to have stayed liquid, warm, and chemically active for a very long stretch.
Modelling suggests it could have. Enceladus is squeezed and flexed by Saturn’s gravity as it orbits, and that tidal kneading generates heat, plausibly enough to keep the ocean liquid and the vents running over geological timescales. If those models are right, the ocean has had the kind of long, stable history in which, on Earth, life took hold.
This is the part to hold loosely. How much heat the tides actually supply, and how old and stable the ocean really is, are still debated, and the estimates carry real uncertainty. That the ocean could have lasted long enough for life to emerge is a reasonable inference from the models, not a settled fact, and it is a statement about opportunity rather than about anything actually being there.
Habitable is not inhabited
That distinction is the one worth keeping in view. Everything Cassini found describes a place where life could plausibly survive, not evidence that it does. A warm, salty, chemically rich ocean is a promising address. It is not a tenant.
Confirming whether anything lives in that ocean would take a mission built for the job, flying through the plume with instruments designed to look for the signatures of biology, or landing to sample the fresh snow of ocean spray that falls back onto the surface. Concepts for exactly that kind of mission have been proposed, and Enceladus sits high on the list of places worth the trip. For now, the honest summary is the most interesting one. A tiny moon is handing us samples of a hidden sea that has much of what life needs, and we do not yet know what, if anything, is in it.
In late 2023, Voyager 1 stopped making sense. The spacecraft was still transmitting from interstellar space, but the data coming back was unreadable, a repeating pattern with no usable information in it. Over the months that followed, NASA engineers traced the fault to corrupted memory in one of the probe’s onboard computers, worked out a way around it, sent the fix across more than 24 billion kilometres, and then waited roughly 45 hours to find out whether it had worked.
It had.
The repair stands as one of the hardest pieces of remote maintenance ever pulled off.
When the signal turned to noise
The trouble began on 14 November 2023. Voyager 1 kept sending a carrier signal, so engineers knew it was alive and pointed at Earth, but the stream of science and engineering data had collapsed into a single stuck pattern. The fault lay in the flight data subsystem, the computer that packages the spacecraft’s readings before they are sent home.
Diagnosis at this distance is slow work. A command takes about 22.5 hours to reach Voyager 1, and any reply takes another 22.5 hours to return, so every question put to the spacecraft carries a near two-day wait for the answer. In March 2024, engineers sent a command nudging the computer to return a full readout of its memory, and that readout finally showed them the problem.
A single bad chip
About 3 per cent of the flight data subsystem’s memory had been corrupted. The cause was a single chip that had failed, taking with it a section of memory that happened to hold part of the software the computer runs. With that code unreadable, the system could no longer assemble data properly.
The chip could not be repaired or replaced.
It is a piece of 1970s hardware sitting beyond the edge of the solar system. Whatever the fix was going to be, it had to work around the dead memory rather than restore it.
Moving the code around the damage
The solution was, in effect, to rehouse the orphaned software. Engineers took the affected code, divided it into sections small enough to fit into the working parts of the memory, tucked those sections into different spare locations, and then rewrote the internal cross-references so the pieces would still call on each other and run as a single program.
They sent the first part of that fix on 18 April 2024. About 22.5 hours later it reached the spacecraft, and on 20 April Voyager 1 returned readable engineering data for the first time in five months. Further commands over the following weeks restored the flow of science data from its instruments. The patch had landed, and it held.
Why this was so hard
The difficulty was not only the distance, though the distance is the part that catches the eye. The team was editing software written for 1970s computers, in a system with a tiny fraction of the memory in a modern key fob, using documentation that is in places nearly half a century old. The engineers who designed it have largely retired or died.
And there is no second attempt without a cost. With a 45-hour round trip on every command, each test of an idea is a two-day commitment, and there is no possibility of anyone going out to lay hands on the hardware. The repair was carried out entirely through a thread of radio signal stretched across more than 24 billion kilometres.
Voyager 1 launched in 1977 and is now the most distant human-made object there is. Its power supply is fading by a few watts a year, and the mission team has been switching off instruments to stretch what remains, with the goal of keeping the probe alive into the 2030s. The memory fix did not add power or fuel. What it bought was time, and the chance for the oldest working spacecraft we have to keep reporting from a place nothing else has reached.
The line turns on a single word, and the word is doing more work than it first appears. To understand others is knowledge, something gathered and held. To understand oneself is something else, a state the original Chinese marks with the character ming (明). As Sandra Hill writes for Monkey Press, the character “can be translated as brightness, clarity, illumination, enlightenment.” It is built, fittingly, from the characters for sun (日) and moon (月). Knowledge of others is an accumulation. Self-knowledge, in this reading, is a light.
That distinction is the whole of the verse. Why has it survived twenty-five centuries, and does the gap it names between knowing others and knowing oneself hold up when modern researchers go looking for it?
The verse comes from Chapter 33 of the Tao Te Ching, the principal Taoist text traditionally attributed to Lao Tzu, the “Old Master” usually placed in the sixth century BC. Modern scholarship tends to treat the figure as semi-legendary and the authorship as uncertain, but the text itself, eighty-one chapters, has outlasted every argument about who wrote it.
Part of why the line travels so well is that it survives translation with its core intact. The Chinese reads 知人者智，自知者明. In the Gia-fu Feng and Jane English rendering, it becomes “Knowing others is wisdom; Knowing the self is enlightenment.”
Before going further, a note on register. We are writers reading across philosophy and psychology, not clinicians or credentialed researchers, and the studies below describe patterns across groups of people rather than verdicts about any individual reader.
The psychologist Tasha Eurich has spent years probing the kind of gap Lao Tzu names. In her account on the Blanchard LeaderChat podcast, “Our data reveals that 95 percent of people believe they are self-aware, but the real number is 12 to 15 percent.” Those figures come from her own studies rather than a settled cross-field consensus, so they are best read as one researcher’s finding, not a fixed law. The direction is the interesting part: most people are confident they see themselves clearly, and far fewer actually do.
There is an obvious objection to Lao Tzu’s hierarchy. Surely we have privileged access to our own minds. We can hear our own thoughts; we cannot hear anyone else’s. Shouldn’t self-knowledge be the easy half?
Well, some research suggests the privilege backfires. Psychologist Emily Pronin and Matthew Kugler studied what they call the introspection illusion. When assessing their own bias, participants weighed their introspective sense over the evidence of what they actually did, a generosity they did not extend to others.
That is perhaps the obstacle the verse quietly implies. Knowing others, you have only their actions to go on, and actions are honest in a way intentions often are not. Knowing yourself, you have access to the running commentary, the reasons, the good intentions, and that flood of inside information is exactly what makes the view unreliable.
If any of this lands close to home, a qualified counsellor or therapist is a good person to talk it through with.
There is a spot in the South Pacific so far from any coastline that, when the International Space Station passes overhead, the astronauts on board are often the nearest human beings to it. The crew sits about 400 kilometres up. The nearest land is more than six times farther away, and there is no one living on it.
The place is called Point Nemo, and the claim about the astronauts is, with one fair qualification, true.
The most remote spot in any ocean
Point Nemo is the oceanic pole of inaccessibility, the single point in the world’s oceans farthest from any land. It sits at roughly 48.9 degrees south and 123.4 degrees west, and the nearest land in any direction is more than 2,688 kilometres away, according to the United States National Oceanic and Atmospheric Administration.
Three uninhabited specks of land sit at that same distance: Ducie Island, part of the Pitcairn group, to the north; Motu Nui, a tiny islet near Easter Island, to the north-east; and Maher Island, off the coast of Antarctica, to the south. None of them has anyone on it. The result is a circle of empty ocean roughly 22 million square kilometres across with no people in it at all.
The point was not stumbled upon by a ship. It was calculated in 1992 by a survey engineer, Hrvoje Lukatela, using geospatial software to find the place on the globe most distant from any coastline. The name is a nod to Captain Nemo from Jules Verne, and to the Latin word it comes from, which means “no one”.
Why the astronauts are closer
The Space Station orbits at around 400 kilometres of altitude. Point Nemo’s nearest land is nearly 2,700 kilometres away, and the nearest actual people are much farther than that, since the closest land is bare rock. The region also sits well away from the major shipping lanes, so on most days there is no vessel anywhere near it.
Put those together and the arithmetic is simple. When the Station’s orbit, tilted at about 51.6 degrees, carries it over that part of the southern ocean, the crew overhead really is the closest cluster of humans to the spot.
The fair qualification is the phrase “when it passes overhead”. The Station is not above Point Nemo continuously, and a passing ship would change the answer. But for a place this empty, the nearest people being a few hundred kilometres straight up rather than thousands of kilometres sideways is often exactly the situation.
The spacecraft cemetery
The same emptiness that makes Point Nemo remote has given it a second job: it is where spacecraft go to die.
Because the area is so far from anyone, space agencies use the ocean around Point Nemo as the disposal zone for hardware brought down from orbit. The Russian space station Mir was steered to a fiery end here in 2001, and cargo ferries and defunct satellites have followed, aimed at the one part of the planet where falling debris is least likely to reach a person.
The biggest arrival is still to come. NASA has contracted a dedicated deorbit vehicle to bring the International Space Station down at the end of its life, around 2030, into this same stretch of remote water. The astronauts who are now, on certain passes, the closest people to Point Nemo are flying the very station that is expected to end up in it.
The closest place to space
There is a neat inversion in all of this. The most isolated location on the surface of the ocean is, on a regular basis, one of the closest places on Earth to people in space, and one of the few places we deliberately point things falling out of orbit.
The remotest patch of sea, in other words, has more to do with what is above it than with anything around it.
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