The NASA Exoplanet Exploration Program (ExEP) has a curated list of 164 nearest Sun-like stars that are easily visible from Earth. This list represents the first targets for a proposed large space telescope specially designed to find life in the universe, currently known as the Habitable Worlds Observatory (HWO). 

After the HWO is completed, likely sometime in the 2040s, scientists will use the specialized telescope to directly image planets in those star systems. The telescope will search around Sun-like stars for planets in a region known as the habitable zone, where temperatures allow liquid water to exist. Scientists hope to find Earth-like planets with liquid water in the habitable zones of other stars.

While the 164 stars on ExEP’s list have qualities that make them good candidates for study, it remains unknown how many actually have terrestrial planets within their habitable zones. A team of scientists at Arizona State University used simulated data for ExEP’s 164 stars and their hypothetical planetary systems to assess which are most likely to have habitable worlds. Their results would help the HWO prioritize which star systems to observe.

The team started with a subset of 134 stars on ExEP’s list with no known exoplanets, giving researchers the freedom to simulate potential worlds around them. They used a software model called the DYNAmical Multi-planet Injection TEster (DYNAMITE) to predict the possibility that an unseen planet exists around each star by generating 100,000 simulated planetary systems around it. The simulations use mathematical formulas based on observations of real exoplanets to determine the sizes and orbital characteristics of hypothetical gas giants and rocky exoplanets. DYNAMITE then determines whether these planetary systems would be stable and include a terrestrial exoplanet in the star’s habitable zone.

The other 30 stars in the ExEP’s list have known exoplanets, but none of them are rocky planets in habitable zones. To predict whether these stars have unseen terrestrial planets in their habitable zones, the team used the same DYNAMITE process as before with the additional requirement that each star must have an exoplanet matching the one already found.

To increase the chances of finding a terrestrial planet in a habitable zone, the team also investigated potentially habitable moons orbiting gas giants in these systems. For each simulation that included a gas giant, the team inserted between 2 and 23 moons, with masses between 10% of Earth’s Moon and 50% of Earth. Then they simulated the surface temperatures of these moons based on how much starlight they receive and how strongly their host planet pulls on them. They deemed the moons potentially habitable if they were large enough to retain an atmosphere and had a temperature ideal for liquid water, even if they were not technically in their stars’ habitable zones.

For each star, the team calculated a metric based on the probabilities that the star had a terrestrial planet in its habitable zone, that the planet would remain in a stable habitable zone for at least 2 billion years, and that the star had a potentially habitable moon. They called this probability statistic a ranking metric and used it to compare star systems. 

Based on the ranking metric, the team found that the dimmer and cooler stars on their list generally had better chances of hosting a habitable-zone terrestrial planet than the brighter, hotter stars. They also found that stars without known exoplanets ranked more favorably. Around 70% of the stars with known exoplanets had less than a 1% probability of hosting a terrestrial planet in their respective habitable zones. Additionally, fewer than 0.1% of their simulated moons were habitable.

Overall, the researchers concluded that the HWO should prioritize observing cooler, Sun-like stars with no known exoplanets. They claimed that the exoplanets with known characteristics in their sample set were of sizes and in positions that made it unlikely for other exoplanets to be in their systems’ habitable zones. Even with expanded habitability criteria for moons, it would be very unlikely for HWO to find another Earth orbiting a gas-giant exoplanet. They ranked 47 stars in the highest-priority category (A Tier), 51 stars in the middle category (B Tier), and 66 stars in the lowest category (C Tier) to observe with HWO. 

At the end of their study, the team remarked that the proposed HWO represents a potential next step in the search for other Earths, but scientists still need to identify the best targets for this future telescope. The HWO telescope should be able to image rocky exoplanets directly, so thorough research to prepare a list of high-priority targets will help avoid overlooking other Earths.

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Carbon is the 4th most abundant element in the universe. It’s everywhere, from the air you breathe to the carbohydrates in your food to the petroleum in the Earth’s crust. Like most elements, carbon was not created by the Big Bang, but came from 2 different types of stars that fuse lighter elements together. 

Massive stars at least 8 times the Sun’s mass fuse 3 helium atoms into a carbon atom in their cores, through a mechanism called the triple-alpha process. They eventually expel this carbon into space, either through a stream of material called a stellar wind or at the end of their lives during a core-collapse supernova. 

Meanwhile, low-to-intermediate-sized stars between ½ and 8 times the Sun’s mass also induce the triple-alpha process. But unlike massive stars, they produce carbon not in their cores, but in a dense shell of helium that surrounds them during an advanced stage known as the asymptotic giant branch or AGB. AGB stars undergo cycles of swelling and contraction, during which they shed some of their material into space.

While scientists understand these processes, the contribution of each star type to the carbon supply in the universe remains uncertain. To address this, a team of scientists modeled how the chemical elements in the Milky Way Galaxy change over time with different contributions from the 2 carbon-creating processes. They then verified their findings by comparing them with the actual carbon concentration in the Milky Way.

To obtain the benchmark for the Milky Way Galaxy’s carbon content, the team turned to the catalog of stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. They selected 14,066 stars that were large and bright enough to yield reliable data but, unlike AGB and massive stars, were still at a stage of life when their newly produced carbon was still confined to their cores. The researchers used the carbon in the outer layers of these stars, known as subgiants, as a compositional record of the gas from which they formed, thereby estimating the Galaxy’s carbon content during their formation. 

The scientists started with a computer program developed by another team that models how the Milky Way’s chemistry changes over time. First, the team calculated the potential amount of carbon produced by different types of stars using estimates from earlier studies. Then, they incorporated these results into a model that accounts for how stars form, fuse elements, and release carbon into the Galaxy, using a simulation program called the Versatile Integrator for Chemical Evolution, or VICE. The researchers ran 14 versions of this model, each assuming a different contribution of carbon from AGB stars relative to massive stars.

In their computer model, the Milky Way Galaxy began as a set of 200 concentric rings, each containing its own population of stars, different speeds at which stars form, and varying amounts of gas available to form new stars. The team then stitched these rings together by having stars migrate between them. They allowed these model Galaxies to settle over 10 billion years, then picked a random sample of 14,066 simulated stars to compare their carbon content with carbon in the same number of observed subgiants from APOGEE.

The team’s model most closely reproduced the actual carbon content of the Milky Way’s subgiant stars when AGB stars contribute between 10% and 40% of the Galaxy’s carbon, with the strongest agreement occurring at 15% to 30%. Even though they found that massive stars are the dominant source of carbon, they also found that smaller AGB stars could produce carbon more efficiently than previously thought, though they take longer to become carbon sources than their larger counterparts.

The team concluded that their estimates of how much carbon comes from AGB and massive stars provide a benchmark for future studies, as the connection between the production of elements inside stars and the processes by which those same stars lose mass remains poorly understood. They suggested that future researchers analyze larger sample sizes, examine other galaxies, and use data from future surveys to better understand the chemical history of the universe.

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Astronomers and astrobiologists use a wide range of tools in their search for extraterrestrial life. Probes, satellites, and rovers take photographs and collect data on the geology and chemistry of planets and moons in the solar system. Radio telescopes sweep the sky, looking for signals from intelligent civilizations. And telescopes like the JWST can observe the atmospheres of distant exoplanets, potentially finding ones similar to Earth’s. 

A limitation of these methods is that they assume life on other worlds is fundamentally similar to life on Earth, requiring the same balance of molecules in the atmosphere, producing the same chemicals for their metabolic processes, or developing technologies analogous to those humans make. While researchers use these assumptions as baseline markers to look for, assuming such similarities might lead them astray. Scientists looking for life using too narrow a set of parameters might miss life unlike Earthlings. Or they might mistake coincidentally similar geological, chemical, or astronomical processes for having been made by living things.

So, to complement techniques that assume alien life resembles life on Earth, scientists also consider approaches that detect signs of life while making as few assumptions as possible about what it could look like, known as agnostic biosignatures. One of these life signs with few assumptions is complexity. Though it can be difficult to quantify precisely, living things tend to create more complex systems than nonliving things. A team of researchers recently tested whether living and nonliving worlds could be distinguished solely by examining the complexity of the light-reflection patterns from their surfaces.

For this, the team treated Earth and Mars, similar planets but one with life and one without, as stand-ins for exoplanets around other stars. They collected data on the light reflected off both planets’ surfaces from a space station monitoring Earth, known as the Deep Space Climate Observatory or DSCOVR, and an orbiter around Mars observing its atmosphere, known as the Hope Probe. 

The team identified 3 nearly identical wavelengths of light that these machines observe from their respective planets. From the machine databases, they collected measurements of how much light each planet reflected, called its reflectance, at these 3 wavelengths over 486 local days. By using only individual wavelengths of light rather than full photographs, the team claimed that, if their test worked, researchers could apply it to distant exoplanets that cannot be photographed in detail.

Without looking for any particular chemical or signal, the team compared these measured reflectances using a series of statistical tests to determine the variation and randomness in their reflected light, which they considered representative of the complexity of the planets’ surfaces. The researchers found that of the 27 complexity metrics they tested, Earth scored higher than Mars on 25, Mars scored higher than Earth on 1, and the planets scored the same on 1. So, even though both planets have rocky surfaces with atmospheres, weather, and cyclical changes, the one with life is measurably more intricate and dynamic, and the researchers found this difference detectable even with a small stream of light at great distances.

The researchers claimed their test demonstrated that complexity could be a valid agnostic biosignature, with caveats. One is that Earth is quite distinct from Mars, in that it has oceans and a relatively thick atmosphere. This means that processes like making and dispersing clouds and the sharp contrast between land and water could add complexity to Earth’s measurements without direct ties to living things. 

They suggested 2 possible explanations for how these complicating factors relate to life on Earth. Either life allows Earth to have these factors, or Earth is inherently complex regardless of life, and therefore it can’t be used to assess how life leads to measurable complexity. To say which is the case, one would have to replicate this test with a lifeless copy of Earth. However, the team argued that Earth’s biosphere is unlikely to be wholly unrelated to its water cycle.

To bolster the validity of their methods, the team plans to expand their sample of planets to include Venus, Saturn’s moon Titan, and simulated exoplanets with modeled biochemistry and atmospheres. If the model holds up, their methodology could represent a new category of mission to find alien life, with long searches for variations in reflected light uncovering properties of distant worlds that would otherwise go unnoticed.

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Our basic understanding of core-collapse supernovae hasn't changed in decades. Large stars burn through all the fuel at their cores and start creating heavier elements in reactions that consume energy. The lack of energy from these reactions allows gravity to pull the interior of the star in on itself, collapsing it into a neutron star or black hole. The energy released by this process then blows the remainder of the star apart.

And, generally, that's right. But there's an entire busload of devils in the details. The statistics of supernovae that we've observed indicate that the model may be seriously incomplete. And on the theoretical side, there are still plenty of uncertainties, including over some of the basics, such as whether all core collapses actually result in a supernova.

A paper being released by Physical Review D provides what might be a potential explanation for the discrepancy: flavor-changing neutrinos. Neutrinos play a key role in our current models of supernovae, and right now, those models don't take into account one of neutrinos' most striking features: their ability to change identity.

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© Ken Chen, Academia Sinica Institute of Astronomy and Astrophysics

Our basic understanding of core-collapse supernovae hasn't changed in decades. Large stars burn through all the fuel at their cores and start creating heavier elements in reactions that consume energy. The lack of energy from these reactions allows gravity to pull the interior of the star in on itself, collapsing it into a neutron star or black hole. The energy released by this process then blows the remainder of the star apart.

And, generally, that's right. But there's an entire busload of devils in the details. The statistics of supernovae that we've observed indicate that the model may be seriously incomplete. And on the theoretical side, there are still plenty of uncertainties, including over some of the basics, such as whether all core collapses actually result in a supernova.

A paper being released by Physical Review D provides what might be a potential explanation for the discrepancy: flavor-changing neutrinos. Neutrinos play a key role in our current models of supernovae, and right now, those models don't take into account one of neutrinos' most striking features: their ability to change identity.

Read full article

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© Ken Chen, Academia Sinica Institute of Astronomy and Astrophysics

The secret to Bennu’s astonishing fragility may be the dust it does not have.

Harvard-Smithsonian Center for Astrophysics scientists studying water ice believed to be stored in the Moon’s ‘pits of eternal darkness’ have concluded that there likely isn’t enough of this critical resource to support long-term future human colonies, meaning visions of large-scale cities on Earth’s largest natural satellite may be more science fiction than science fact.

Conversely, the researchers calculated that smaller settlements with fewer than 10,000 human colonists could have enough accessible water to survive for centuries. They also suggested that other technological advances in water harvesting or advances in scanning techniques that explore below the top few meters of surface regolith may reveal significant amounts of hidden lunar water.

Water Ice Stored in Moon’s Pits of Eternal Darkness

The Moon’s surface is covered with visible evidence of asteroid collisions. Along with its textured appearance, some of these massive impact craters contain areas that are permanently shaded from direct sunlight.

The Harvard-Smithsonian research team behind the new study said some of the earliest “pits of eternal darkness” could be over one million years old. More critically, they can maintain a temperature of 110K, or just above absolute zero. At this low temperature, frozen water ice trapped in the sunless craters won’t lose more than a millimeter of thickness to space every billion years.

When announcing the new study, the researchers noted that “a succession of Moon-orbiting missions” has mapped out possible locations of stored water ice since 2013. The results suggested that the Moon’s pits of eternal darkness may contain as much as a billion tons, with the largest concentrated around the Moon’s northern and southern poles.

Since those missions, scientists and industrialists have begun to speculate about the viability of long-term human lunar habitation. Unlike astronauts trapped in capsules or space stations, lunar colonists could theoretically possess enough on-site water to support farming, full-service bathroom facilities, and production of hydrogen-based fuels.

Still, researchers wondered if one billion tons of stored water ice is enough to support the types of cities that billionaire industrialists and science fiction authors have proposed.

On-Site Solar Power Could Support One-Million-Person Lunar City

To start, the team modeled how long large human settlements ranging from 100,000 to one million people could survive on the water stored in lunar pits of eternal darkness. This included water-recycling rates up to 98%, as achieved on the International Space Station (ISS).

After running the numbers, the team found mixed results.

First, even colonies up to one million humans wouldn’t run out of power. The team said that number is based on solar power generation and excludes nuclear reactors.

Instead, the Harvard-Smithsonian team proposed constructing one-kilometer-tall solar energy towers near the rims of the craters. Their models suggest that an array of towers covered in photovoltaic arrays could generate three gigawatts of usable electricity.

The team noted that the materials needed to build solar panels, including the primary ingredient, silicon, are plentiful on the Moon, meaning future lunar colonists could manufacture new solar power-generating towers on-site. Such lunar colonists could theoretically maintain enormous AI data centers near these towers capable of servicing paying customers back on Earth.

“That would be the start of a true lunar economy,” the research team explained.

Even Generous Water Ice Estimates Limit Large Lunar Colonies

When the researchers crunched the water numbers, long-term lunar habitability became significantly more dubious. In fact, most estimates had future lunar colonists exhausting the most generous one-billion-ton projected supply of water ice within “a few years.”

When researchers modeled an ISS-level water recycling efficiency level using those same water estimates, a colony of one million humans would run out of water “in just over a century.”

“And today’s best estimates of the amount of water on the Moon are about 30 times less than a billion tons, shortening the time to water exhaustion by the same factor,” they add.

For example, if more conservative ‘pits of eternal darkness’ water ice estimates are closer to reality, the researchers said that “even a small city” likely wouldn’t make it past a decade before they had tapped the Moon dry.

Untapped Sources Could Improve Long-Term Habitation Prospects

Fortunately, the news was not all bad. When the team assumed a smaller “Moon village” of over one thousand people, up to a larger settlement of 10,000, the researchers found that the water ice stored in the Moon’s pits of eternal darkness “would instead be sustainable for several centuries or more.”

The team also suggested alternate solutions for supporting a larger, long-term lunar settlement. These included potential improvements in water recycling, improved farming efficiency, or mining nearby asteroids for water.

The team also noted that additional pockets of stored lunar water ice may be awaiting discovery, suggesting that finding such lunar water may be easier than achieving sufficient farming and recycling efficiency improvements.

“Current water surveying techniques do not reach below the surface more than a few meters, while the rubble-like rocks of the surface regolith typically extend tens of meters down and may contain water in the cold traps,” they explained.

The study “No Cities on the Moon: a Billion Tons of Water is not enough for Sustainability” was published in Frontiers in Space Technology. 

Christopher Plain has spent the last six years as Associate News Editor and Head Science Reporter at The Debrief. Follow and connect with him on X, learn about his novels at plainfiction.com, or email him at christopher@thedebrief.org.

Ancient meteorite minerals reveal a surprisingly strong magnetic field from the solar system’s first 200,000 years. About 4.6 billion years ago, before the Sun and planets existed in their familiar forms, the solar system was a vast cloud of gas and dust. Within a few million years, this “solar nebula” collapsed and flattened into a [...]

Astronomers once thought winds generated by supermassive black holes affected only their host galaxies, but a recent study found that their energy can also reach surrounding galaxies. Winds from a supermassive black hole can carry energy far beyond the galaxy that contains it. New observations show that this influence can extend roughly 300,000 light-years and [...]

Using NASA’s Chandra X-ray Observatory, scientists have discovered a new class of objects behaving unlike any they have seen before. Astronomers suggest these newly spotted objects in other galaxies may help solve not one, but two long-standing questions in astrophysics.

These mysterious objects give off unusually low-energy X-rays but intense levels of ultraviolet radiation. This discovery is featured in a paper published Wednesday in Nature Astronomy.

“We’ve never encountered a group of objects that act like this,” said Mustafa Muhibullah of the University of Alabama who led the study. “Of course, the next step was to try to figure out what these things are.”

The researchers found a total of 84 of these “hypersoft X-ray sources” – so named because they give such low-energy X-rays – in the six different galaxies they searched, using data openly available to the public in the Chandra archive. Two of the galaxies are spirals, M31 (the Andromeda galaxy) and M101 (the Pinwheel galaxy), while the other four are ellipticals. They found hypersoft X-ray sources both in regions of active star formation and areas where there are older stars.

The team spotted the sources by finding objects that appeared in Chandra images taken at the lowest X-ray energies but vanished in higher-energy images. That means these objects give off far more low-energy X-rays than high-energy ones. Because low-energy X-rays border energetic ultraviolet radiation on the electromagnetic spectrum, the researchers determined that these sources are producing large amounts of energetic ultraviolet radiation as well.

It is unclear what types of objects are responsible for these low-energy X-rays and intense ultraviolet radiation. The team thinks they most likely involve a black hole, neutron star, or white dwarf pulling material from a companion star. The material pulled from the companion star is heated up to produce X-rays before falling onto the white dwarf or neutron star, or into the black hole. Such binary systems have been seen before, but not with such bright ultraviolet radiation and low-energy X-rays.

The discovery suggests that there may be large populations of binary systems with energetic ultraviolet radiation that have been undetected until now.

“These clandestine X-ray sources are actually among the most energetic objects in galaxies, and they could be solving two cosmic mysteries at once,” said Muhibullah.

Scientists think that some white dwarf systems pulling material from companion stars may eventually explode as a supernova – known as a Type Ia – that is critical for measuring the expansion of the universe. These supernovae played a key role in discovering that this expansion is accelerating. Astronomers have been looking for the stars that turn into Type Ia supernovae for many years, so far without success.

“If we could find a way to spot these Type Ia supernova explosions before they go off, that would be really important,” said co-author Jimmy Irwin, also of the University of Alabama. “Right now, we study them after they’ve exploded, and astronomers have struggled to understand what is actually ignited.”

The other mystery these hypersoft X-ray sources might explain is what strips electrons from gas between the stars in some galaxies. This stripping of electrons is important to probe because it can affect how quickly stars form and influence the life cycles of galaxies. Hot, massive stars play a role, but they do not completely explain what is causing this stripping. The intense levels of ultraviolet radiation from the hypersoft X-ray sources may play a vital role.

Why were these hypersoft X-ray sources not found until now? In addition to the low-energy X-ray output, which is very difficult for X-ray telescopes to detect, the high-energy ultraviolet radiation is readily absorbed by helium and hydrogen gas that fills the space between the stars, creating a nearly impenetrable barrier to look through.

“By combing through the Chandra archive, we were able to eliminate what used to be a blind spot for telescopes,” said co-author Rosanne Di Stefano of the Center for Astrophysics | Harvard & Smithsonian. “That’s how we found what appears to be a new class of cosmic objects with remarkable qualities.”

NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Read more from NASA’s Chandra X-ray Observatory

To learn more about NASA’s Chandra mission, visit:

https://www.nasa.gov/chandra

Visual Description

This release features a composite image of a spiral galaxy, M101; one of six identified galaxies housing a new class of mysterious objects that give off unusually low-energy X-rays.

In this composite image, M101 faces us directly. It has multiple arms in shades of purple, spiraling clockwise around a golden yellow core. Scattered along and between the arms are scores of tiny specks in white and purple. Most of those specks are pairs of stars, but seven of them are a mystery.

To casual observers, the unusual objects are visually indistinguishable from the other specks of light in the galaxy. An annotated version of the composite image is included in this release, with red circles around the mysterious specks for easy identification.

These mystery specks behave like no other class of object discovered before. The curious objects give off X-rays of such low energy, they in fact produce large amounts of ultraviolet radiation, as UV radiation borders X-rays on the electromagnetic spectrum. Searching images of galaxies with low-energy X-rays in the Chandra Observatory archive, scientists have found a total of 84 such objects spread across M101 and five other galaxies. They have dubbed these mysterious objects “hypersoft X-ray sources.”

For the first time, astronomers have pointed NASA’s two flagship space telescopes at the same patch of sky beyond Neptune and let them work as a team. Hubble handled the visible light. Webb handled the infrared. Together, they picked out 27 previously unknown trans-Neptunian objects, or TNOs — small, icy bodies that drift in the […]

A photon, or particle of light, from the biggest cosmic explosion since the Big Bang, nicknamed "the BOAT" (for the brightest of all time), should not have reached Earth. That is, unless it defied rules defined by Einstein. Now scientists may know how it did this, with new research suggesting how the high-energy photon may have survived a journey of more than two billion light-years without being absorbed.

The BOAT, a gamma-ray burst officially designated GRB 221009A, was first detected on Oct. 9, 2022. Among the ocean of photons from the event that rained down on our planet was the highest-energy photon ever detected originating from a gamma-ray burst. It was detected by Carpet, an ultra-high-energy cosmic-ray detector located at the Baksan Observatory in the Russian Caucasus.

The problem is, according to all current rules of physics, a particle with such high energy shouldn't reach Earth from an explosion occurring such a vast distance away. That's because space isn't empty; it is filled with a "fossil" radiation field of photons left over from just after the Big Bang called the cosmic microwave background (CMB). It should be virtually impossible for a high-energy photon to travel 2 billion light-years without interacting with a CMB photon and being transformed. And still it came.

"We started from a very simple question: how did this photon survive a journey that, according to known physics, should have destroyed it?" team leader Giorgio Galanti from the Italian National Institute for Astrophysics (INAF) said in a statement. "The new data from the Carpet experiment showed us that the explanations proposed so far were no longer sufficient.

"We therefore looked for a theoretical scenario capable of consistently describing what we observe, without resorting to arbitrary corrections to the equations."

A hypothetical transformation

To investigate the mystery of how this high-energy photon reached our planet, Galanti and colleagues turned to incredibly light hypothetical particles called axion-like particles (ALPs).

ALPS could serve as a solution to this puzzle via a mechanism that would allow photons to transform into ALPs as they travel and then convert back into photons as they reach the Milky Way. The problem is that this still can't account for such a high-energy photon.

This team combined the idea of ALPs with a proposed violation of one of the fundamentals of Einstein's 1905 theory of special relativity called "Lorentz invariance."

In short, Lorentz invariance says that observers moving at different speeds should experience the same physical laws. The team tested the idea that Lorentz invariance could be violated at high energies, thus changing how photons propagate through space.

In the scenario devised by the team the photon would have avoided being wiped out by interactions with the CMB as it would avoid interactionc with these fossil photons.

The new research therefore implies that at high enough energies, photons can take a "fast lane" through a transparent universe, dodging the physics that would normally force their destructive transformation.

Interestingly, there is some evidence relating to the BOAT that seemingly backs this theory. According to the picture developed by the team, this high-energy photon should have arrived at Earth around one hour after lower-energy particles of light originating from the BOAT. Indeed, that is exactly what happened.

"The most interesting aspect of our work is that, for the first time, it brings together two ideas that until now had been developed separately," team member Marco Roncadelli of the National Institute for Nuclear Physics (INFN) said. "If future observations confirmed this scenario, the universe would become a natural laboratory for studying quantum gravity at energies enormously higher than those achievable by any accelerator built on Earth."

The team's research is available on the repository site arXiv and has been accepted for publication in the journal Physical Review Letters.

Physicists around the world remain deeply divided on key mysteries of the universe, from dark matter to quantum gravity. The standard cosmological model failed to gain majority support, and no leading theory dominated the survey results. The largest survey ever conducted among physicists worldwide reveals surprisingly little agreement on some of the field’s biggest mysteries, [...]

Beyond the solar system, the line between planet and star can get blurry. Astronomers call objects that fall between the size ranges of planets and stars substellar objects. One type of substellar object, called a brown dwarf, forms from collapsing gas clouds like a star, but is not quite massive enough to fuse hydrogen in its core. Some can briefly fuse a heavier form of hydrogen, known as deuterium, in their cores, though never enough to produce starlight. Others are small and cold enough to develop complex atmospheres.

Recently, astronomers discovered a new type of substellar object in a star-forming region of the Milky Way Galaxy called IC 348. Using observational data from the JWST’s Near InfraRed Spectrograph (JWST NIRSpec), they found objects 0.2% to 1.2% the mass of the Sun that float freely like stars but have carbon-containing molecules called hydrocarbons in their atmospheres. Because these objects are smaller than known brown dwarfs and have evidence of hydrocarbons, scientists refer to them as H-type objects.

To investigate what H-type objects are and where they fit within the spectrum of substellar objects, researchers Richard J. Parker and Catarina Alves de Oliveira analyzed survey data on stars and substellar objects in IC 348, then conducted follow-up simulations to uncover how H-type objects formed. The main question they asked was whether H-type objects form from collapsing gas clouds, like brown dwarfs and stars, or develop around host stars before being ejected and drifting freely through space, like planets.

First, they reviewed the observational records of IC 348 obtained with the JWST NIRSpec and the near-IR spectrograph SpeX at the NASA Infrared Telescope Facility. IC 348 has 495 stars and brown dwarfs combined, as well as 9 H-type objects. Estimates for the age of this star-forming region range from either 1 to 3 million years or 5 to 6 million years, depending on how different teams calculated it. From there, Parker and Alves de Oliveira compared where the stars, brown dwarfs, and H-type objects were located within the cluster. They found no unique spatial distribution among the 3 types of objects.

Then, the team simulated the evolution of IC 348 over 10 million years to determine which initial conditions would result in a spatial distribution closest to the survey data. They simulated an initial giant gas cloud and used a mathematical function to distribute its mass among the 495 constituent objects. The researchers then placed a Jupiter-sized planet around each simulated star that was approximately the Sun’s mass to determine whether they could grow and escape their home star and become H-type objects. They also repeated the simulations by placing the Jupiter-sized planets at distances from the Sun similar to those of Earth, Jupiter, and Neptune, and varied the sizes and star densities of the simulated IC 348 regions.

They found that if Jupiter-sized planets orbited their stars at roughly Jupiter’s distance from the Sun, then 5 to 15 of them could escape their stars in a region like IC 348, which would roughly match the number of known H-type objects. However, the escaped planets were distinctly more spread-out than the observed H-type objects, which share a similar spatial distribution with the cluster’s stars and brown dwarfs. Since the simulations did not match the observed distribution, the researchers suggested that these H-type objects are likely a new sub-category of very small brown dwarfs rather than escaped planets.

Although this study favors a brown dwarf origin for H-type objects, the exact details of how they formed remain up for debate. Astronomers still have multiple competing theories about how ordinary brown dwarfs form. Perhaps they are ejected from their gas cloud before fully forming, have their outer layers stripped by radiation from a nearby massive star, or simply form like stars on a slightly smaller scale. Regardless, future researchers will continue to explore this murky area of substellar astronomy.

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Dark matter, the invisible substance thought to make up around 85 percent of all mass in the universe, forms an essential part of the standard cosmological model, providing the gravitational glue that holds together entire galaxies. What it actually is, though — and even if it truly exists — remains one of the great mysteries of science.

Now, a bizarre event that occurred nearly a mile underground at the world’s largest dark matter detector in South Dakota, the LZ detector, could be the first direct evidence of the substance. Or it could be something else entirely. Either way, it has scientists mystified and excited.

In a new paper published Tuesday and has been submitted to the journal Physical Review Letters, physicists running the LZ Dark Matter Experiment say that their detector recorded a stunning subatomic interaction that doesn’t fit anything else ever documented in physics.

Again, it’s not necessarily a dark matter discovery — but it’s so unusual that it warranted sharing.

“How do you even make sense of one event?” Tom Shutt, a particle astrophysicist at SLAC National Accelerator Laboratory and cofounder of the LZ project, told Science magazine. “We just decided we should publish and think really, really, really hard about what that event could be.”

Dark matter is a sort of ghost haunting the cosmos. We can’t see it because it doesn’t emit, absorb, or reflect light, or otherwise interact with any ordinary matter — except through gravity. 

We see the fingerprints of its gravitational pull all around the universe, in fact. Galaxies aren’t massive enough to hold themselves together with their own gravity, so without the invisible presence of something with incredible mass, the very realms that define the universe, and which we call home, would fly apart.

There are countless candidates for what dark matter is, but the prevailing theory is that it’s made up of weakly interacting massive particles, or WIMPs. As their feeble acronym suggests, WIMPs are thought to be a hundred times as massive as a proton, but have such a weak nuclear force that they don’t interact with ordinary particles. 

Because of their mass, they move much slower than ordinary particles, too, allowing them to clump together and form giant “halos” that provide the gravitational pull for galaxies to form in. There is no single agreed-upon definition of a WIMP, though, and it’s possible that WIMPs could be a whole family of particles, rather than just one.

If these theories are correct, then every once in a while, errant WIMPs can bump into the nucleus of an unsuspecting atom and create a trace amount of energy.

This is what the LZ detector is built to find. It’s essentially a tank filled with seven tons of liquid xenon, placed 1,480 meters underground in a former gold mine. At such a depth, the preponderance of xenon is shielded from the space radiation that our planet is routinely bombarded with (though there is a still a background level of other interactions that scientists can’t control, but can account for.) Anything that causes a a big enough stir in this controlled, quiet environment would be significant.

After spending years poring over the data the detector has collected so far, the physicists found a striking interaction that took place in 2023. Something, we don’t know what, smashed into a xenon particle, and produced a flash of light. If it was dark matter, it produced more energy than traditional WIMP models predict.

The scientists say that the detection has about a one in 400 chance of being a fluke. Scientific discoveries, though, need to meet at least a five sigma threshold, meaning that there should be only as roughly one in 3.5 million that it’s a fluke.

Still, physicists are absolutely thrilled. Even if this event isn’t a smoking gun by itself, there are other, larger dark matter detectors coming online, such as China’s PandaX experiment and Italy’s XENONnT, that should be able to hunt for the same high energy type of event.

“We can perform this study independently with a blind analysis to validate or invalidate LZ’s claim,” Elena Aprile, a physicist at Columbia University and spokesperson for the XENON experiment, told Science.

More on dark matter: Physicist Proposes Dark Matter Is Made of Black Holes That Survived Dead Universes

The post Something Strange Just Happened With the World’s Largest Dark Matter Detector appeared first on Futurism.

The dark matter search LUX-ZEPLIN has announced that they have made a detection that could be the first ever evidence for a dark matter particle. Just what have they measured, what could it be, and what does it mean? I have a brief summary.

In November of last year, scientists warned of a “severe” solar storm, the strongest in over two decades, colliding with the Earth.

Solar storms are the result of a surge in solar activity, with the Sun unleashing a barrage of charged particles that can trigger spectacular auroras — and wreak havoc with communications satellites and radio signals — when they reach the Earth’s magnetosphere.

Beyond being ferocious enough to delay the launch of a Mars-bound NASA spacecraft, the storm wreaked absolute havoc with GPS systems back on the ground for hours at a time. As detailed in a new paper published in the journal Geophysical Research Letters, a team of scientists found that global navigation satellite systems experienced “significant positioning errors” of over 33 feet during the superstorm, “large enough to disrupt precision agriculture and autonomous transportation industries” across the continental United States.

That’s enough risk to warrant a careful study on these types of events can impact human activity on Earth.

“The results underscore the importance of accurate understanding of various space weather phenomena to enhance our predictive capabilities through coordinated observations and physics‐based modeling and ultimately reducing disruptions to RF applications during space weather events,” the paper reads.

The researchers analyzed observations from several scientific instruments spread out across the US to watch the chaos unfold last November. The Aurora Oval, a ring-shaped area of pronounced activity around the Earth’s geomagnetic north pole where auroras conventionally occur, was pushed south toward the equator. This triggered a “horizontally extended band of intense density gradients” in the upper atmosphere, causing fluctuations in how long signals take to travel through it.

The result: “significant positioning errors at mid-latitudes,” the researchers noted.

The researchers also found that as the auroras became brighter, the observed irregularities became more intense, deteriorating GPS accuracy accordingly.

Fortunately, while farming equipment like GPS-equipped tractors would’ve likely been affected, the November storm occurred long after the farming season concluded.

However, that wasn’t the case for the May 2024 superstorm, which scientists estimate cost farmers half a billion dollars in damages.

“Had the November superstorm occurred during the farming season in the American sector, it could have caused significant economic losses for the American farming industry, in addition to affecting the autonomous transportation industry,” the paper reads.

More on the solar storm: Scientists Say the Largest Solar Storm in Two Decades Is About to Blast Earth

The post Researchers Alarmed as GPS Readings Suddenly Veer Off by 33 Feet, Enough to Crash Self-Driving Cars appeared first on Futurism.

An astrophysicist has claimed that some unidentified anomalous phenomena that were observed in recent years in the United States might be warp drives. He has written a paper about it in which he calculates how such a warp drive would look. I have a brief summary.

The post Astronomers discover the existence of a ‘black hole star’ appeared first on MIT School of Science.

The post Astronomers discover a new kind of cosmic object – a black hole ‘star’ appeared first on MIT School of Science.