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Category: evolution – Page 22

In the case of NiPS3, the researchers observed an intermediate symmetry breaking which leads to a vestigial order. Just as the term “vestigial” refers to the retention of certain traits during the process of evolution, the vestigial order here can also be viewed as the retention during the process of symmetry breaking.

This happens when the primary magnetic long-range order state melts or breaks down into a simpler form, in the NiPS3 case, a 2D vestigial order state (known as Z3 Potts-nematicity), as the material is thinned. Unlike conventional symmetry breaking, which involves the breaking of all symmetries, vestigial order only involves the breaking of some symmetries.

While there are numerous examples from a theoretical standpoint, experimental realizations of vestigial order have remained challenging. However, the investigation of this 2D magnetic material has shed the first light on this issue, demonstrating that such a phenomenon can be observed through dimension crossover.

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How did a giant impact 4 billion years ago affect Jupiter’s moon, Ganymede? This is what a recent study published in Scientific Reports hopes to address as a researcher from Kobe University investigated the geological changes known as a “furrow system” that Ganymede has exhibited since being struck by a giant asteroid in its ancient past, along with confirming previous hypotheses regarding the size of the asteroid. This study holds the potential to help scientists better understand how the very-active early solar system not only contributed to Ganymede’s but how such large impacts could have influenced the evolution of planetary bodies throughout the solar system.

“The Jupiter moons Io, Europa, Ganymede and Callisto all have interesting individual characteristics, but the one that caught my attention was these furrows on Ganymede,” said Dr. Naoyuki Hirata, who is an assistant professor in the Department of Planetology at Kobe University and sole author of the study. “We know that this feature was created by an asteroid impact about 4 billion years ago, but we were unsure how big this impact was and what effect it had on the moon.”

For the study, Dr. Hirata used a series of mathematical calculations to ascertain the size of the object that impacted Ganymede billions of years ago along with the angle of impact that produced the furrow system. In the end, Dr. Hirata determined that the impactor’s radius was approximately 93 miles (150 kilometers) and the angle of impact was potentially between 60 to 90 degrees, resulting in the furrows that overlay a significant portion Ganymede’s surface. For context, Ganymede is not only the largest moon in the solar system at a radius of 1,637 miles (2,634 kilometers), but it is also larger than the planet Mercury.

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A new study published in The Astrophysical Journal, led by Assistant Professor of Astronomy Rana Ezzeddine and UF alumnus Jeremy Kowkabany, with collaborators, reports the discovery of a star that challenges astronomers’ understanding of star evolution and formation of chemical elements, and could suggest a new stage in their growth cycle.

It is widely accepted that as stars burn, they lose lighter elements like lithium in exchange for heavier elements like carbon and oxygen, but an analysis of this new star revealed that not only was its lithium content high for its age, but was higher than the normal level for any star at any age.

This star, named J0524-0336 based on its coordinates in space, was discovered recently by Ezzeddine as part of a different study that used surveying to look for older stars in the Milky Way. It is an evolved star, meaning that it is in the later stages of its “life” and is beginning to grow unstable. That also means that it is much larger and brighter than most other stars of its type, estimated to be about 30 times the size of the sun.

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We use the new simulation capabilities of the extended-magnetohydrodynamic (MHD) code, M3D-C1, to investigate the nonlinear MHD properties of a reactor-scale quasisymmetric stellarator equilibrium. Our model captures the self-consistent evolution of the magnetic field, temperature, density, and flow profiles without imposing restrictions on the structure of the first. We include the effects of resistivity using a realistic temperature-dependent Spitzer model, along with a model for heat transport that captures the key physical characteristic, namely, strongly anisotropic diffusion in directions perpendicular and parallel to the magnetic field. We consider a quasi-axisymmetric, finite-pressure equilibrium that was optimized for self-consistent bootstrap current, quasi-symmetry, and energetic particle confinement. Our assessment finds that the equilibrium is highly unstable to interchange-like pressure-driven instabilities near the plasma edge. The initially unstable modes rapidly destabilize other modes in the direction of the N-fold rotational symmetry (toroidal, in this case). For this equilibrium, N = 2, meaning destabilization of a large number of even-numbered toroidal Fourier modes. Thus, field-periodicity is likely to be an important factor in the nonlinear MHD stability characteristics of optimized stellarators.

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A University of Maryland-led study reveals new details about asteroid dynamics following NASA ’s DART mission, which intentionally collided with the asteroid moon Dimorphos in 2022. The impact significantly altered Dimorphos’ trajectory and shape, leading to unexpected gravitational behaviors. These findings challenge previous assumptions about asteroid evolution and could influence future planetary defense strategies and space missions, as researchers continue to assess the system’s stability and potential for further exploration.

When NASA’s Double Asteroid Redirection Test (DART) spacecraft collided with an asteroid moon called Dimorphos in 2022, the moon was significantly deformed—creating a large crater and reshaping it so dramatically that the moon derailed from its original evolutionary progression—according to a new study. The study’s researchers believe that Dimorphos may start to “tumble” chaotically in its attempts to move back into gravitational equilibrium with its parent asteroid named Didymos.

“For the most part, our original pre-impact predictions about how DART would change the way Didymos and its moon move in space were correct,” said Derek Richardson, a professor of astronomy at the University of Maryland and a DART investigation working group lead. “But there are some unexpected findings that help provide a better picture of how asteroids and other small bodies form and evolve over time.”

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What were galaxies like in the early universe? This is what a recent study published in The Astronomical Journal hopes to address as an international team of researchers investigated the formation and evolution of galaxies in the early universe, as recent studies have suggested they were much larger than cosmology models had simulated. This study holds the potential to help researchers better understand the conditions in the early universe and how life came to be.

“We are still seeing more galaxies than predicted, although none of them are so massive that they ‘break’ the universe,” said Katherine Chworowsky, who is a PhD student at the University of Texas at Austin and lead author of the study.

For the study, the researchers used NASA’s James Webb Space Telescope to peer deep into the universe’s past and observe some of the earliest galaxies to ascertain their sizes and whether they are as massive as recent studies have suggested. After analyzing the data, the researchers discovered that black holes residing at the center of these galaxies are creating false brightness and sizes, meaning these galaxies are much smaller than previously thought, thus reducing the panic within the scientific community regarding cosmological models. However, this study does suggest further research is necessary regarding star formation and evolution within these galaxies.

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Berkeley scientists have discovered a new choanoflagellate species in Mono Lake that forms multicellular colonies and hosts a microbiome, offering new perspectives on the evolution of multicellular organisms.

The salty, arsenic-and cyanide-laced waters of the Eastern Sierra Nevada’s Mono Lake is an extremely hostile environment. Aside from the abundant brine shrimp and black clouds of alkali flies, very few organisms live there.

Now, researchers from the University of California, Berkeley have discovered a new creature lurking in the lake’s briny shallows — one that could tell scientists about the origin of animals more than 650 million years ago.

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“Those tiny objects with masses comparable to giant planets may themselves be able to form their own planets,” said Dr. Aleks Scholz.

What can rogue planets teach us about the formation and evolution of stars and planets? This is what a recent study published in The Astronomical Journal hopes to address as an international team of researchers investigated NGC 1,333, which is a star-forming cluster located just under 1,000 light-years from Earth. This study holds the potential to help scientists better understand the formation and evolution of stars and planets while challenging previous hypotheses about these processes.

“We are probing the very limits of the star forming process,” said Dr. Adam Langeveld, who is an assistant research scientist at Johns Hopkins University and lead author of the study. “If you have an object that looks like a young Jupiter, is it possible that it could have become a star under the right conditions? This is important context for understanding both star and planet formation.”

For the study, the researchers used NASA’s James Webb Space Telescope to observe brown dwarfs that comprise NGC 1,333 in hopes of learning more about how stars form. in the end, the researchers discovered six new rogue planet candidates—officially called free-floating planetary-mass objects (FFPMOs)—with masses ranging between 5–10 Jupiters and that exhibit dusty disks orbiting them. This indicates they are some of the smallest objects formed from processes that are traditionally responsible for creating stars and brown dwarfs, the latter of which never reach appropriate sizes to produce nuclear fusion in their cores.

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What did NASA’s Double Asteroid Redirection Test (DART) spacecraft on the asteroid moon, Dimorphos, teach astronomers about altering the trajectory of asteroids and asteroids’ formation and evolution? This is what a recent study published in The Planetary Science Journal hopes to address as an international team of researchers investigated the potential geological changes made to Dimorphos, which orbits its parent asteroid, Didymos, when DART impacted the former in September 2022. This study holds the potential to help scientists better understand the formation and evolution of asteroids throughout, and potentially beyond, the solar system, which could hold implications for the early history of the solar system, as well.

“For the most part, our original pre-impact predictions about how DART would change the way Didymos and its moon move in space were correct,” said Dr. Derek Richardson, who is a professor of astronomy at the University of Maryland, a DART investigation working group lead, and lead author on the study. “But there are some unexpected findings that help provide a better picture of how asteroids and other small bodies form and evolve over time.”

For the study, the researchers analyzed post-impact data of the DART spacecraft on Dimorphos based on predictions made prior to the impact, which could help in planning for the European Space Agency’s upcoming Hera spacecraft mission to Didymos, which is slated to launch in October 2024 and arrive at Didymos in December 2026. In the end, the researchers found that along with Dimorphos’ orbital parameters being influenced by the impact, its physical shape was altered, as well. This resulted in the small asteroid moon becoming elongated towards its poles, whereas its poles were squished prior to impact. This indicates varying formation and evolutionary processes regarding its geologic composition.

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