Jan 12, 2021 05:37 AM
(This post was last modified: Jan 12, 2021 06:24 AM by C C.)
Striped or spotted? Winds and jet streams found on the closest brown dwarf
https://www.eurekalert.org/pub_releases/...010721.php
EXCERPT: . . . He and his team found that brown dwarfs look strikingly similar to Jupiter. The patterns in the atmospheres reveal high-speed winds running parallel to to the brown drawfs' equators. These winds are mixing the atmospheres, redistributing heat that emerges from the brown dwarfs' hot interiors. Also, like Jupiter, vortices dominate the polar regions.
Some atmospheric models predicted this atmospheric pattern, Apai said, including models by the late Adam Showman, a UArizona Lunar and Planetary Laboratory professor and a leader in brown dwarf atmosphere models.
"Wind patterns and large-scale atmospheric circulation often have profound effects on planetary atmospheres, from Earth's climate to Jupiter's appearance, and now we know that such large-scale atmospheric jets also shape brown dwarf atmospheres," said Apai, whose co-authors on the paper include the Astronomical Observatory of Padua's Luigi Bedin and Domenico Nardiello, who is also affiliated with Laboratoire d'Astrophysique de Marseille in France.
"Knowing how the winds blow and redistribute heat in one of the best-studied and closest brown dwarfs helps us to understand the climates, temperature extremes and evolution of brown dwarfs in general," Apai said... (MORE - details)
Is dark matter just made of "antimatter nuggets"?
https://massivesci.com/articles/dark-mat...eoretical/
EXCERPTS: In a recent study, physicists wondered whether the mysterious dark matter could actually consist of plain old antimatter, because, well, there is nothing that would in principle prevent this. The researchers at Case Western Reserve University and Vanderbilt University followed a recent trend, asking whether dark matter can take the form of “nuggets” of particles bounded together and floating in interstellar space. They worked from existing data that they hoped would say something about the presence or absence of antimatter nuggets throughout the Milky Way and the universe at large.
But if these chunks of antimatter are found in the sky, couldn’t some of them fall to Earth as meteorites and hit people? The researchers thought of that [...] The absence of all these phenomena did not rule out anti-nuggets completely; more precisely, it did rule out anti-nuggets larger than a few kilometers per side, while it constrained the range of the mass that anything smaller could have. So the research is not completely finished.
Given the necessary constraints placed on them, if the nuggets actually exist, their constituent parts would have to be held together quite tightly, so that they would be more dense than atoms and perhaps even nuclei (the densest portions of the atom which are around 1010 times more dense than everyday matter). The researchers wouldn't want to exclude this possibility yet: according to Glenn Starkman, a physicist who co-authored the study, “We are going to have to look under every lamppost we can find, without prejudging whether it is likely to find the dark matter there." (MORE - details)
https://www.eurekalert.org/pub_releases/...010721.php
EXCERPT: . . . He and his team found that brown dwarfs look strikingly similar to Jupiter. The patterns in the atmospheres reveal high-speed winds running parallel to to the brown drawfs' equators. These winds are mixing the atmospheres, redistributing heat that emerges from the brown dwarfs' hot interiors. Also, like Jupiter, vortices dominate the polar regions.
Some atmospheric models predicted this atmospheric pattern, Apai said, including models by the late Adam Showman, a UArizona Lunar and Planetary Laboratory professor and a leader in brown dwarf atmosphere models.
"Wind patterns and large-scale atmospheric circulation often have profound effects on planetary atmospheres, from Earth's climate to Jupiter's appearance, and now we know that such large-scale atmospheric jets also shape brown dwarf atmospheres," said Apai, whose co-authors on the paper include the Astronomical Observatory of Padua's Luigi Bedin and Domenico Nardiello, who is also affiliated with Laboratoire d'Astrophysique de Marseille in France.
"Knowing how the winds blow and redistribute heat in one of the best-studied and closest brown dwarfs helps us to understand the climates, temperature extremes and evolution of brown dwarfs in general," Apai said... (MORE - details)
Is dark matter just made of "antimatter nuggets"?
https://massivesci.com/articles/dark-mat...eoretical/
EXCERPTS: In a recent study, physicists wondered whether the mysterious dark matter could actually consist of plain old antimatter, because, well, there is nothing that would in principle prevent this. The researchers at Case Western Reserve University and Vanderbilt University followed a recent trend, asking whether dark matter can take the form of “nuggets” of particles bounded together and floating in interstellar space. They worked from existing data that they hoped would say something about the presence or absence of antimatter nuggets throughout the Milky Way and the universe at large.
But if these chunks of antimatter are found in the sky, couldn’t some of them fall to Earth as meteorites and hit people? The researchers thought of that [...] The absence of all these phenomena did not rule out anti-nuggets completely; more precisely, it did rule out anti-nuggets larger than a few kilometers per side, while it constrained the range of the mass that anything smaller could have. So the research is not completely finished.
Given the necessary constraints placed on them, if the nuggets actually exist, their constituent parts would have to be held together quite tightly, so that they would be more dense than atoms and perhaps even nuclei (the densest portions of the atom which are around 1010 times more dense than everyday matter). The researchers wouldn't want to exclude this possibility yet: according to Glenn Starkman, a physicist who co-authored the study, “We are going to have to look under every lamppost we can find, without prejudging whether it is likely to find the dark matter there." (MORE - details)