Scientists have identified supermagnetic macrophages in the livers of homing pigeons (Columba livia domestica) that appear essential for navigation when the Sun is not visible, pointing to an entirely new mechanism for animal magnetoreception.
The post Pigeons May Sense Earth’s Magnetic Field Using Superparamagnetic Immune Cells in Their Livers appeared first on Sci.News: Breaking Science News.
Researchers suggest that old psychoanalytic ideas and modern brain science may be describing the same mental processes from different angles. More than a century after Sigmund Freud developed his influential theories of the mind, some researchers believe modern neuroscience may be arriving at surprisingly similar conclusions. A new paper published in the neurocognitive journal Entropy [...]
Field notebooks from the late Richard Köhler allowed researchers to finally catalog a remarkable fossil tarpon from Aotearoa New Zealand. Recently disclosed notebooks from a late paleontologist supplied the missing details researchers needed to complete their study of a “remarkable” fossil found nearly 30 years ago. Dr. Richard Köhler discovered the fossil fish in 1999 [...]
For 15 years, Sébastien Fontaine has been trying to kill dirt. The biochemist, who runs a lab at the French National Institute for Agriculture, Food, and Environment, wanted to know how much carbon is released by soil — just dirt alone, completely devoid of life. His team sealed dirt into jars and blasted them with sterilizing gamma radiation. Then they waited for the carbon dioxide released by…
Earth has many unique features for a planet, such as a magnetic field, a large moon, and plate tectonics. It’s also the only planet we know of that harbors life. These facts form the basis of the Rare Earth hypothesis, which posits that we haven’t found aliens because other planets in the Galaxy probably don’t have all the right conditions for life.
Another characteristic of Earth is that about 30% of its surface is land and about 70% is ocean. Recently, Columbia University Assistant Professor David Kipping investigated whether the proportion of Earth’s surface covered by dry land versus ocean, or its land fraction, is another reason Earth is habitable not only for simple single-celled organisms, but also for intelligent species like humans.
To test this hypothesis, Kipping created 4 statistical models of planets with different land fractions that intelligent aliens could potentially evolve on. First, he created an equation to describe the likelihood that a planet in its star’s habitable zone has a particular land fraction, known as a probability distribution. Kipping weighted this probability distribution toward the extreme ends, making it more likely that a planet would be covered by a single huge landmass or a single vast ocean than by a mix of both, as on Earth.
Kipping then incorporated this land fraction probability distribution into his statistical models to calculate the probability that a random planet will have that land fraction and host intelligent life. The 4 scenarios Kipping tested were: 1) that intelligent life is more likely to emerge on land-dominated planets, 2) that it’s more likely to emerge on ocean-dominated planets, 3) that it’s more likely to emerge on planets with roughly equal amounts of land and ocean, and 4) that its emergence is independent of a planet’s land fraction.
As a first step in determining the kinds of planets intelligent aliens would tend to emerge on, Kipping used each model to predict the probability that intelligent life would emerge on a planet with the same land fraction as Earth. He then compared these probabilities by calculating the ratios between each value. Because Earth is the only known planet with intelligent life, a model that predicted a greater probability for humanity’s existence on Earth would be more likely to reflect reality.
Kipping considered it strong evidence that a given model was more realistic than another if the ratio between 2 of them was greater than 10, meaning one model was 10 times more likely to predict the existence of Earth and humanity. Kipping found that no comparison of any 2 models passed this threshold. However, the models assuming that intelligent life prefers ocean-dominated planets or planets with a land-ocean balance were 2.5 and 3 times more likely to predict the existence of humanity than the model assuming that intelligent life prefers land-dominated planets. Additionally, the model assuming that intelligent life prefers a land-ocean balance was always more likely to predict humanity than any other model, though marginally.
Kipping also addressed whether finding more planets with intelligent life would affect which model was deemed most realistic, for example, if scientists discovered conclusive evidence of life on Mars in its distant past. Here, Kipping identified 2 complications. First, it’s uncertain how much of Mars’s surface was once covered by water – some estimate it had a land fraction as high as 81%, while others estimate it was as low as 25%. Second, proving that Mars once had life would not prove it once had intelligent life.
Regardless, Kipping reran the models assuming that ancient Mars had a land fraction comparable to Earth’s. Adding this second data point produced ratios similar to those in the earlier Earth-only calculations, meaning it still didn’t make any single model 10 times more likely to predict the existence of humans and Martians, respectively.
Kipping then took the 10-times threshold and reversed the calculations to find what conditions would exceed it. In doing so, he calculated that astronomers would need to find 14 other planets with intelligent life and known land fractions to robustly determine whether intelligent life is more likely to occur on desert planets, ocean planets, balanced planets, or without bias.
Kipping concluded that he can’t yet definitively state whether there is something special about Earth’s land fraction when it comes to producing intelligent species. However, Earth’s existence would suggest that intelligent life is unlikely to favor extreme desert planets, so the Milky Way probably isn’t filled with Tatooines and Jakkus. And while his analysis doesn’t debunk the Rare Earth hypothesis, it does undermine the argument that Earth’s ocean size explains why Earth is rare.
The post Is Earth’s water why intelligent life evolved here? appeared first on Sciworthy.
:max_bytes(150000):strip_icc():format(jpeg)/underwater-view-of-an-algal-bloom---red-tide-with-grunt-fish-505883854-5ae5d2781d640400364dfbd5.jpg "James R.D. Scott / Getty Images")
© James R.D. Scott / Getty Images
Stanford researchers have developed a microscope that can show how nanostructures interact inside living cells at the highest resolution achieved so far. The view into living cells just got better. Stanford researchers have merged two microscopy methods to build a unique instrument that can capture cell structures interacting in real time at an unprecedented resolution [...]
A sesame-seed-sized sea slug discovered in Taiwan is revealing a hidden world of tiny ocean life. A newly identified species of sea slug, so small that it is barely larger than a sesame seed, has been discovered in the coastal waters of Keelung, Taiwan. The tiny marine animal, named Thecacera sesama, features a translucent body [...]
The loss of a queen triggers intense battles for power among female wasps, disrupting the colony’s social structure. Surprisingly, other wasps avoid the fighting and keep the colony functioning by taking care of its most important daily tasks. What happens when a queen suddenly disappears from a wasp colony? According to new research led by [...]
A new evolutionary analysis suggests that modern blood and immune cells may preserve a 700-million-year legacy inherited from ancient single-celled ancestors. Long before humans, dinosaurs, or even fish existed, ancient single-celled organisms may have already carried the genetic blueprint for one of the body’s most important systems: blood. A new study from Kyoto University suggests [...]
Scientists are discovering that some of the cells linked to aging may also be key to staying healthy. A growing body of research is changing how scientists view one of aging biology’s most studied cell types: senescent cells, often called “zombie cells.” While these cells have long been associated with aging and chronic disease, new [...]
Models suggest that impact-ejected material from Earth could reach Venus’ clouds and potentially survive there briefly. Panspermia is the idea that life, or the ingredients needed for life, can move through space on asteroids, comets, and other objects. If life’s building blocks appear on one planet, a powerful impact could blast material from its surface [...]
Artificial streetlights can lure isopods into massive circular processions that may leave them vulnerable to predators. Researchers have made a world-first observation of thousands of Israeli isopods leaving their normally solitary shelters and moving together in huge synchronized “death spirals” caused by artificial streetlights. By testing different light arrangements, the team found that vertical beams [...]
Leishmania parasites appear to evolve through widespread genetic exchange, reshaping assumptions about how they adapt and spread. A parasite long thought to spread mostly by cloning itself may be far more genetically dynamic than scientists once believed. A new international study suggests that Leishmania—a group of microscopic parasites responsible for debilitating tropical diseases—regularly swaps genetic [...]
A remarkable new study of the world’s oldest verified living person reveals a surprising picture of extreme longevity. Maria Branyas lived through two world wars, the 1918 flu pandemic, the Spanish Civil War, and COVID-19. When she died in 2024 at age 117 years and 168 days, she was the oldest verified living person in [...]
Scientists discovered that fog droplets can host living bacteria that grow and help remove harmful pollutants from the atmosphere, revealing fog as a surprisingly active microbial environment. Every breath you take may contain microscopic hitchhikers floating through the atmosphere. Scientists have known for years that bacteria drift through clouds and air currents, but new research [...]
A newly described fossil goose shows that New Zealand’s bird history involved repeated arrivals, extinctions, and rapid island evolution. A rare fossil goose found in the remains of an ancient lake in Central Otago is changing how scientists understand the bird history of Aotearoa New Zealand, according to a researcher at the University of Otago [...]
A newly discovered tiny blue octopus from the Galápagos is a striking reminder that the deep ocean still holds countless secrets. The Galápagos Islands, located off the coast of Ecuador, are famous for their remarkable wildlife. More than a thousand species of plants and animals found there exist nowhere else on Earth, including giant tortoises [...]
Organs, arms, appendages, and other complex tissues usually decay rapidly when they’re separated from their host. Over the years, biologists have seen some success with keeping them alive outside of the body—organ transplants depend on it—but it has always required germ-free environments and nutrient-rich mediums filled with growth factors. Now, though, scientists have discovered bits of tissue removed from a species of sea cucumber called Psolus fabricii can keep on living indefinitely if they’re left in ordinary seawater.
“This is naturally occurring tissue immortality,” said Sara Jobson, a researcher at Memorial University of Newfoundland and lead author of the study. “Having tissues that survive that easily is unheard of. We’ve never seen anything like this.”
Psolus fabricii is a species of sea cucumber that lives in the cold waters of the Atlantic and Arctic oceans. Its bottom side, known as a sole, is soft and ringed by a band of tube feet that it uses to grip rocks. Once on a rock, it extends soft, branching tentacles into the water to feed on suspended particles. Because these sea cucumbers inhabit harsh environments, their feet and tentacles experience high rates of injury and loss. Evolution has therefore endowed these sites with an incredibly high capacity for regeneration.
© Gerald Corsi
Scientists have long known that migrating birds and homing pigeons navigate in part by sensing the Earth's magnetic fields, especially at night or in overcast conditions when visual landmarks or sunshine are in short supply. But exactly where this magneto-sensing occurs in the body—and the mechanism that enables it—remains a matter of intense debate. A new paper published in the journal Science suggests that homing pigeons have iron-rich immune cells in their livers that help them detect magnetic fields and transmit that information to the brain.
There are three primary hypotheses for how birds might sense Earth's geomagnetic field. One is a compass-like mechanism, whereby the Earth exerts a pull on magnetic particles in a bird's upper beak that relays directional information via a large nerve in the cranium. A second is that it happens biologically via cellular ion channels sensitive to voltage, enabling birds to sense changes in the magnetic field. And a third suggests that physical effects on retinal pigments enable birds to detect photons and send signals to the brain, although this mechanism is really only viable in the light.
None fully explain how animals can sense magnetic fields. However, “We had some clues that the liver and spleen have magnetic properties, because they break down red blood cells and so store much iron in the body,” said co-author Clivia Lisowski of the University of Bonn and the University Hospital Bonn. This refers to a 2015 paper suggesting that red pulp macrophages in the spleens of mice and humans are intrinsically superparamagnetic and hence more sensitive to magnetic fields. But it wasn't clear if those properties were involved in any kind of magnetoreception.
© Christian Ziegler/ Max Planck Institute of Animal Behavior
Login