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Yahoo
3 days ago
- General
- Yahoo
When the sun dies, could life survive on the Jupiter ocean moon Europa?
When you buy through links on our articles, Future and its syndication partners may earn a commission. Can life survive in the solar system once the sun dies and becomes a red giant star? New research suggests there may be a narrow window of possibility for life to persist on the icy moons of the outer solar system. It's not exactly clear where the habitable zone of the red giant sun will be, but it could possibly reach the orbit of Jupiter. Although the planet itself won't be habitable because it will still be a giant ball of hydrogen and helium gas, Jupiter's moons might become promising homes for life. That's according to researchers at the Carl Sagan Institute at Cornell University, who reported the theory in a paper accepted for publication in the journal Monthly Notices of the Royal Astronomical Society. In about 4.5 billion years, the sun will enter the final phase of its life. Its core of hydrogen fusion will expand and, in doing so, inflate the outer atmosphere of the star into gross proportions. It will swell and become a red giant star that will engulf Mercury and Venus and incinerate Earth. In the best-case scenario, all that will remain of our planet will be a lump of smoldering iron and nickel. In the worst-case scenario, it will be obliterated. The sun's habitable zone — the band where the influx of radiation is just right to support liquid water on the surface of a planet — will steadily march outward as the sun begins this new phase of life. Jupiter's ice-covered moon Europa will get a lot of heat. Not only will the giant sun be bearing down on it, but Jupiter itself will become hotter and reflect more sunlight, which will provide its own source of heat to the little moon. The researchers found that the icy outer shell will sublimate and the oceans underneath will evaporate. The most sublimation will occur on the side of Europa facing Jupiter because it will receive the most heat. And because of circulation and convection, the equatorial bands that face opposite Jupiter will also suffer significant water loss. RELATED STORIES: —Good news for the alien life hunt: Buried oceans may be common on icy exoplanets —Jupiter's ocean moon Europa may have less oxygen than we thought —10 weird water worlds in the solar system and beyond However, northern and southern latitudes on the anti-Jupiter side of Europa will have a more modest rate of water loss. The researchers found that this could provide a tenuous atmosphere of water vapor that could persist for up to 200 million years. That's a blink of an eye compared with the opportunities life has had to thrive on Earth — but it's not nothing, and Europa may become the home for any life that remains in the solar system in that deep future. The researchers also found that we might be able to find biosignatures on (formerly) icy moons around red giant stars. We have yet to have any confirmed detections of exomoons, but there are several promising candidates. Future observations with the James Webb Space Telescope or the planned Habitable Worlds Observatory might have the resolving power to examine the atmospheric features of these moons. Although it might be an unlikely scenario to find life, it does widen the possible locations for our search, as there may yet be refuges around stars that are nearly dead.
Yahoo
23-05-2025
- Science
- Yahoo
A dozen black holes may be 'wandering' through our galaxy — and they're the rarest type in the universe
When you buy through links on our articles, Future and its syndication partners may earn a commission. The Milky Way has millions of small black holes and one giant supermassive black hole at its center. But does the galaxy have any medium-sized black holes? New research suggests the answer is yes: Perhaps a dozen may inhabit the Milky Way, but they are wandering freely through space and are fiendishly difficult to detect. For decades, researchers have wondered about the prevalence of intermediate-mass black holes (IMBHs). Certainly, every galaxy is capable of producing an enormous number — roughly a handful every century — of small black holes with masses of up to 100 or so times that of the sun. And it appears that when galaxies like the Milky Way first arrived on the cosmic scene, they already had companion supermassive black holes in their hearts. Our own supermassive black hole, Sagittarius A*, has a mass of 4.5 million suns. But what about the IMBHs? Theoretically, they should have masses of 10,000 to 100,000 solar masses. Finding IMBHs — or disproving their existence — has enormous implications for our understanding of black hole growth and evolution. But so far, there have been only faint, sketchy hints of IMBHs residing in dwarf galaxies, and no direct evidence that they live in a galaxy like the Milky Way. In April, a team of researchers at the University of Zurich in Switzerland explored whether our current simulations of the universe could conclusively predict if the Milky Way hosts a population of IMBHs. Their paper has been accepted for publication in the journal Monthly Notices of the Royal Astronomical Society. Related: Is our universe trapped inside a black hole? This James Webb Space Telescope discovery might blow your mind Galaxies do not grow up alone. Instead, they develop through the cannibalization of their neighbors, by incorporating their stars — and any black holes — within their volumes. The Milky Way has consumed over a dozen dwarf galaxies, and probably many more, in its long history. Presumably, some of those dwarf galaxies held IMBHs. But the common assumption was that large black holes tend to slink down the centers of their host galaxies, where they go on to merge with the central supermassive black hole. RELATED STORIES —Physicists create 'black hole bomb' for first time on Earth, validating decades-old theory —James Webb Space Telescope finds a wild black hole growth spurt in galaxies at 'cosmic noon' —Has the James Webb Space Telescope discovered a 'missing' supermassive black hole? (video) Through their models, the researchers saw a different story unfold. They used a simulation of the evolution of a Milky Way-like galaxy and found that it can contain somewhere between five and 18 "wandering" IMBHs, which are not located near the central core but are left to roam within the disk of the galaxy. The exact number of IMBHs depends on whether they are born near the core of a soon-to-be-consumed dwarf galaxy or in its outskirts. Although the researchers were heartened to find that the Milky Way should host a population of IMBHs, they urged caution in interpreting their results. They could not conclusively state what masses these black holes should have or where they would ultimately reside. So, while the new research strongly hints that IMBHs are out there, we do not yet know where to look.
Yahoo
21-05-2025
- Science
- Yahoo
Lightning on alien worlds may fail to spark life, simulations suggest
When you buy through links on our articles, Future and its syndication partners may earn a commission. Life as we know it may require lightning, as it's one of the few energy sources a planet has available to create complex chemical compounds. Now, new research has found that lightning, while not very common, can occur on tidally locked exoplanets like our nearest neighbor, Proxima b. But the peculiar nature of lightning on tidally locked planets poses some challenges for their ability to host life. A typical lightning bolt can reach temperatures of up to 30,000 kelvins (over 50,000 degrees Fahrenheit). That's more than powerful enough to destroy common atmospheric gases and reassemble them into new compounds. On modern-day Earth, lightning breaks down molecular nitrogen and oxygen and creates nitrogen oxides. On the early Earth, however — before the rise in atmospheric oxygen due to photosynthesis — lightning may have played a crucial role in creating many prebiotic compounds, which are molecules that form the building blocks of proteins. We don't know if any exoplanets host life. We have yet to find an Earth twin with the right orbit around a sun-like star, but we have come close. Take Proxima b, an exoplanet that orbits the nearest star to the solar system. Proxima b is roughly the size of Earth and orbits its star, Proxima Centauri, at just the right distance to potentially support liquid water. But Proxima Centauri is a red dwarf star, with just a fraction of the sun's brightness and size. Proxima b has an incredibly tight orbit, with an entire year lasting just 11 days. Because of its proximity to its parent star, Proxima b is almost certainly tidally locked, meaning it always shows one face toward the star, just like the moon always shows only one face toward Earth. Because of its rotation, our planet hosts a rich weather system. This weather system makes lightning storms very common, with roughly 100 lightning strikes happening somewhere on the globe every second. But can a tidally locked planet create lightning storms? To answer this question, a team of researchers led by Denis Sergeev at the University of Bristol in the U.K. created atmospheric simulations of a mock tidally locked planet, using the same kinds of simulations that climatologists use to study Earth's weather. In April, they submitted their paper for publication in the journal Monthly Notices of the Royal Astronomical Society. The researchers found that the tidally locked planet could produce significant lightning storms, but that these storms were far different from those on Earth. These planets around small stars hosted significantly fewer lightning strikes — only a handful of strikes per second, the simulations showed. And that was for planets with much thinner atmospheres than Earth's atmosphere — roughly a quarter of our planet's atmospheric pressure. Higher-pressure atmospheres suppressed the formation of convection cells that could drive cloud formation and generate the necessary friction to produce lightning. Atmospheres with pressures 10 times greater than Earth's could produce only a single lightning strike every few minutes. Unlike on Earth, all the heat from the star pours onto one side on a tidally locked planet. That heat then flows through powerful jet streams that race from the permanent dayside to the nightside. This powered strong weather mostly on the dayside, with lightning strikes clustered in a circular area, the researchers found. However, in some cases, lightning strikes happened mostly on the nightside, just past the day-night terminator line. It was only there that there was enough atmospheric activity to generate the conditions needed for lightning. Related stories: —How could life survive on tidally locked planets? —Was life on Earth sparked by cloud-to-ground lightning strikes? —The 10 most Earth-like exoplanets But that doesn't mean that this lightning could necessarily be guaranteed to help produce life. For one, lightning strikes are far less common there than on Earth and thus may not be enough to generate sufficient prebiotic compounds. Another challenge is that the strikes are not distributed evenly around the globe. They tend to be concentrated on the dayside, which may be too hot to support life. Still, the story of life on exoplanets, even tidally locked ones, is not over. And nature has shown time and time again that life … finds a way.
Yahoo
09-05-2025
- Science
- Yahoo
This Galactic 'Bone' Was Smashed by a Pulsar Clocking Up to 2 Million MPH
The culprit in a cosmic hit-and-run that resulted in a broken 'bone' has been found out. Of course, it's not actually a bone at all, but a mind-blowingly huge filament in the center of the Milky Way galaxy, known as the Snake, extending for a length of 230 light-years. One of the interesting things about this filament is that it's relatively smooth – except for two prominent kinks, or "breaks". The origin of the fractures in the Snake (G359.13) was something of a mystery; observations using the Chandra X-ray Observatory and the MeerKAT radio telescope revealed the culprit of one of them. Zooming in on one of the fractures identified a prominent point-like source of X-rays and radio waves. A team of astronomers, led by Farhad Yusef-Zadeh of Northwestern University in the US, thinks it could only be a radio pulsar that punched through the filament at an absolutely breakneck velocity of between 500 and 1,000 kilometers (310 to 620 miles) per second. This, believe it or not, is not unheard-of for pulsars. That's because pulsars are dead stars – the collapsed cores of massive stars that have reached the end of their lifespan and sneezed off their outer material in a violent supernova. The core of the star, no longer supported by the outward pressure of fusion, collapses under gravity to form a neutron star that, when it pulses with light, we call a pulsar. If this supernova is lopsided, the neutron star can be booted unceremoniously across the galaxy at high speeds, something astronomers call a natal kick. The famous cannonball pulsar is thought to have received a natal kick; and other high-speed stars show just how powerful this blow can be. We don't know the origin of the pulsar smashing through the Snake, but it seems to be doing so with quite some force. The filament is made of magnetic fields, along which spiraling particles are accelerated, causing the filament to glow. Around the fracture, the radio emission glows more strongly, suggesting that the force of the blow warped the magnetic field, distorting the radio signal. Meanwhile, an enhancement in X-rays near the pulsar is consistent with accelerated electrons and positrons. The cause of the second, smaller fracture is yet to be determined. There is also more to discover about the pulsar. If it's traveling fast enough, it may some day leave the galaxy. But since it's in the galactic center, some 26,000 light-years from us, it has a long road ahead of it. A paper describing these findings was published in May 2024 in the Monthly Notices of the Royal Astronomical Society. Giant Impacts Could Trigger Seismic Vibrations Lasting Millions of Years Scientists Have a Radical Plan to Grab a Sample of Venus's Toxic Atmosphere JWST Helps Decipher Mysterious Nature of Hot Alien World
India Today
02-05-2025
- Science
- India Today
Mega collision in Milky Way galaxy fractured its bone. We have a picture
Astronomers have discovered a huge fracture in the cosmic bone of the Milky Way galaxy and Nasa has released an image of what it appears like.X-ray data from Chandra and radio data from the MeerKAT radio array in South Africa show the cosmic bone dubbed G359.13 by Nasa. Nasa researchers looked closely at the mysterious structure and revealed the presence of a break, or fracture, in the otherwise continuous length of have discovered an X-ray and radio source at the location of the fracture, using the data from Chandra and MeerKAT and the National Science Foundation's Very Large Array. NASA/CXC/Northwestern Univ./F. Yusef-Zadeh et al; Radio: NRF/SARAO/MeerKat; Image Processing: NASA/CXC/SAO/N. Wolk The fracture is likely caused by a pulsar that smashed into G359.13 at a speed between one million and two million miles per hour.A pulsar is a highly magnetised, rotating neutron star that emits beams of electromagnetic radiation from its magnetic poles. These beams sweep across space like lighthouse beams, and when one of them points toward Earth, we see a regular pulse of radiation. Typically about 20 kilometres in diameter but more massive than the Sun. They can rotate extremely fast—some spin hundreds of times per collision between the pulsar and the cosmic bone happened at a staggering speed of one million and two million miles per hour. This new image shows one of these cosmic 'bones'. (Photo: Nasa) At about 230 light-years long, G359.13 is one of the longest and brightest of these structures in the Milky Way. To put this into context, there are more than 800 stars within that distance from Earth. G359.13 is located about 26,000 light-years from Earth, near the centre of the Milky details of the findings have been published in the Monthly Notices of the Royal Astronomical Reel
