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Categories: Paleontology: Early Mammals and Birds, Space: Structures and Features
Published How the 'heart and lungs' of a galaxy extend its life
(via sciencedaily.com) Original source Galaxies avoid an early death because they have a 'heart and lungs' which effectively regulate their 'breathing' and prevent them growing out of control, a new study suggests. If they didn't, the universe would have aged much faster than it has and all we would see today is huge 'zombie' galaxies teeming with dead and dying stars. That's according to a new study that investigates one of the great mysteries of the Universe -- why galaxies are not as large as astronomers would expect.
Published Scientific definition of a planet says it must orbit our sun; A new proposal would change that
(via sciencedaily.com) Original source The International Astronomical Union defines a planet as a celestial body that orbits the sun, is massive enough that gravity has forced it into a spherical shape, and has cleared away other objects near its orbit around the sun. Scientists now recognize the existence of thousands of planets, but the IAU definition applies only to those within our solar system. The new proposed definition specifies that the body may orbit one or more stars, brown dwarfs or stellar remnants and sets mass limits that should apply to planets everywhere.
Published Dark matter in dwarf galaxy tracked using stellar motions
(via sciencedaily.com) Original source The qualities and behavior of dark matter, the invisible 'glue' of the universe, continue to be shrouded in mystery. Though galaxies are mostly made of dark matter, understanding how it is distributed within a galaxy offers clues to what this substance is, and how it's relevant to a galaxy's evolution.
Published First ever 3D reconstruction of 52,000-year-old woolly mammoth chromosomes thanks to serendipitously freeze-dried skin
(via sciencedaily.com) Original source An international research team has assembled the genome and 3D chromosomal structures of a 52,000-year-old woolly mammoth -- the first time such a feat has been achieved for any ancient DNA sample. The fossilized chromosomes, which are around a million times longer than most ancient DNA fragments, provide insight into how the mammoth's genome was organized within its living cells and which genes were active within the skin tissue from which the DNA was extracted. This unprecedented level of structural detail was retained because the mammoth underwent freeze-drying shortly after it died, which meant that its DNA was preserved in a glass-like state.
Published Mars likely had cold and icy past, new study finds
(via sciencedaily.com) Original source The question of whether Mars ever supported life has captivated the imagination of scientists and the public for decades. Central to the discovery is gaining insight into the past climate of Earth's neighbor: was the planet warm and wet, with seas and rivers much like those found on our own planet? Or was it frigid and icy, and therefore potentially less prone to supporting life as we know it? A new study finds evidence to support the latter by identifying similarities between soils found on Mars and those of Canada's Newfoundland, a cold subarctic climate.
Published The origins of dark comets
(via sciencedaily.com) Original source Up to 60% of near-Earth objects could be dark comets, mysterious asteroids that orbit the sun in our solar system that likely contain or previously contained ice and could have been one route for delivering water to Earth, according to a new study.
Published Strong evidence for intermediate-mass black hole in Omega Centauri
(via sciencedaily.com) Original source Most known black holes are either extremely massive, like the supermassive black holes that lie at the cores of large galaxies, or relatively lightweight, with a mass of under 100 times that of the Sun. Intermediate-mass black holes (IMBHs) are scarce, however, and are considered rare 'missing links' in black hole evolution.
Published Found with Webb: A potentially habitable icy world
(via sciencedaily.com) Original source A international team of astronomers has made an exciting discovery about the temperate exoplanet LHS 1140 b: it could be a promising 'super-Earth' covered in ice or water.
Published Building materials for water-rich planets in the early solar system
(via sciencedaily.com) Original source Age data for certain classes of meteorite have made it possible to gain new findings on the origin of small water-rich astronomical bodies in the early solar system. These planetesimals continually supplied building materials for planets -- also for the Earth, whose original material contained little water. The Earth received its actual water through planetesimals, which emerged at low temperatures in the outer solar system, as shown by computational models carried out by an international research teach with participation by earth scientists.
Published Stench of a gas giant? Nearby exoplanet reeks of rotten eggs, and that's a good thing
(via sciencedaily.com) Original source An exoplanet infamous for its deadly weather has been hiding another bizarre feature -- it reeks of rotten eggs, according to a new study of data from the James Webb Space Telescope.
Published Fresh wind blows from historical supernova
(via sciencedaily.com) Original source A mysterious remnant from a rare type of supernova recorded in 1181 has been explained for the first time. Two white dwarf stars collided, creating a temporary 'guest star,' now labeled supernova (SN) 1181, which was recorded in historical documents in Japan and elsewhere in Asia. However, after the star dimmed, its location and structure remained a mystery until a team pinpointed its location in 2021. Now, through computer modeling and observational analysis, researchers have recreated the structure of the remnant white dwarf, a rare occurrence, explaining its double shock formation. They also discovered that high-speed stellar winds may have started blowing from its surface within just the past 20-30 years. This finding improves our understanding of the diversity of supernova explosions, and highlights the benefits of interdisciplinary research, combining history with modern astronomy to enable new discoveries about our galaxy.
Published Giant salamander-like creature was a top predator in the ice age before the dinosaurs
(via sciencedaily.com) Original source Meet Gaiasia jennyae, the swamp creature with a toilet seat-shaped head. It lived 40 million years before the first dinosaurs, and it was the top predator in its ecosystem.
Published Extinct humans survived on the Tibetan plateau for 160,000 years
(via sciencedaily.com) Original source Bone remains found in a Tibetan cave 3,280 m above sea level indicate an ancient group of humans survived here for many millennia.
Published The evidence is mounting: humans were responsible for the extinction of large mammals
(via sciencedaily.com) Original source Human hunting, not climate change, played a decisive role in the extinction of large mammals over the last 50,000 years. This conclusion comes from researchers who reviewed over 300 scientific articles from many different fields of research.
Published Tiny bright objects discovered at dawn of universe baffle scientists
(via sciencedaily.com) Original source A recent discovery by NASA's James Webb Space Telescope (JWST) confirmed that luminous, very red objects previously detected in the early universe upend conventional thinking about the origins and evolution of galaxies and their supermassive black holes.
Published Too many missing satellite galaxies found
(via sciencedaily.com) Original source Bringing us one step closer to solving the 'missing satellites problem,' researchers have discovered two new satellite galaxies.
Published The density difference of sub-Neptunes finally deciphered
(via sciencedaily.com) Original source The majority of stars in our galaxy are home to planets. The most abundant are the sub-Neptunes, planets between the size of Earth and Neptune. Calculating their density poses a problem for scientists: depending on the method used to measure their mass, two populations are highlighted, the dense and the less dense. Is this due to an observational bias or the physical existence of two distinct populations of sub-Neptunes? Recent work argues for the latter.
Published Last surviving woolly mammoths were inbred but not doomed to extinction
(via sciencedaily.com) Original source The last population of woolly mammoths was isolated on Wrangel Island off the coast of Siberia 10,000 years ago, when sea levels rose and cut the mountainous island off from the mainland. A new genomic analysis reveals that the isolated mammoths, who lived on the island for the subsequent 6,000 years, originated from at most 8 individuals but grew to 200--300 individuals within 20 generations. The researchers report that the Wrangel Island mammoths' genomes showed signs of inbreeding and low genetic diversity but not to the extent that it can explain their ultimate (and mysterious) extinction.
Published Precision instrument bolsters efforts to find elusive dark energy
(via sciencedaily.com) Original source Dark energy -- a mysterious force pushing the universe apart at an ever-increasing rate -- was discovered 26 years ago, and ever since, scientists have been searching for a new and exotic particle causing the expansion. Physicists combined an optical lattice with an atom interferometer to hold atoms in place for up to 70 seconds -- a record for an atom interferometer -- allowing them to more precisely test for deviations from the accepted theory of gravity that could be caused by dark energy particles such as chameleons or symmetrons. Though they detected no anomalies, they're improving the experiment to perform more sensitive tests of gravity, including whether gravity is quantized.
Published Shocked quartz reveals evidence of historical cosmic airburst
(via sciencedaily.com) Original source Researchers continue to expand the case for the Younger Dryas Impact hypothesis. The idea proposes that a fragmented comet smashed into the Earth's atmosphere 12,800 years ago, causing a widespread climatic shift that, among other things, led to the abrupt reversal of the Earth's warming trend and into an anomalous near-glacial period called the Younger Dryas.