This artist’s concept shows what happened when two massive clusters of galaxies, collectively known as MACS J0018.5, collided: The dark matter in the galaxy clusters (blue) sailed ahead of the associated clouds of hot gas, or normal matter (orange). Both dark matter and normal matter feel the pull of gravity, but only the normal matter experiences additional effects like shocks and turbulence that slow it down during collisions.Credit: W.M. Keck Observatory/Adam Makarenko
The research provides a unique look at how this matter decoupling proceeds. Astronomers have untangled a messy collision between two massive clusters of galaxies in which the clusters’ vast clouds of dark matter have decoupled from the so-called normal matter...
Simulation of the light emitted by a supermassive black hole binary system where the surrounding gas is optically thin (transparent). Viewed from 0 degrees inclination, or directly above the plane of the disk. The emitted light represents all wavelengths. Credit: NASA’s Goddard Space Flight Center/Scott Noble; simulation data, d’Ascoli et al. 2018
Researchers have found a link between some of the largest and smallest objects in the cosmos: supermassive black holes and dark matter particles.
Their new calculations reveal that pairs of supermassive black holes (SMBHs) can merge into a single larger black hole because of previously overlooked behavior of dark matter particles, proposing a solution to the longstanding “final parsec problem” in astronomy.
Dark matter is a hypothetical form of matter that is implied by gravitational effects that can’t be explained by general relativity unless more matter is present in the universe than can be seen. It remains virtually as mysterious as it was nearly a century ago when first suggested by Dutch astronomer Jan Oort in 1932 to explain the so-called “missing mass” necessary for things like galaxies to clump together.
Now Dr. Richard Lieu at The University of Alabama in Huntsville (UAH) has published a paper in the Monthly Notices of the Royal Astronomical Society that shows, for the first time, how gravity can exist without mass, providing an alternative theory that could potentially mitigate the need for dark matter.
The new population of dark main sequence of stars (top) on the Hertzsprung-Russell diagram found by this paper compared to the standard main sequence (bottom) for stellar evolution. Credit: arXiv (2024). DOI: 10.48550/arxiv.2405.12267
Stars near the center of our galaxy are acting kind of weird. Dark matter may be the explanation. A team of scientific detectives (so to speak) have discovered a potential new class of stars that could exist within a light-year of the Milky Way’s center that could be operating according to an unusual mechanism: dark matter annihilation. This process would produce an outward pressure on the stars other than hydrogen fusion, keeping them from gravitationally collapsing—and making them essentially immortal, their youth being refreshed constantly...
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