astrophysics

New gravitational-lensing study hints at problems for dark matter models

Enlarge / The massive galaxy cluster MACSJ 1206. Embedded within the cluster are the distorted images of distant background galaxies, seen as arcs and smeared features. NASA, ESA, G. Caminha, M. Meneghetti, P. Natarajan, and the CLASH team. While the idea of dark matter was originally proposed to explain the structure of galaxies, one of …

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Researchers propose a supernova triggered the Late Devonian mass extinction

Enlarge / The Cassiopeia A supernova which left this remnant behind occurred about 11,000 light years away—much too far to pose a significant threat—and its wavefront likely reached Earth about 300 years ago. NASA/JPL-Caltech A paper released this week by University of Illinois Urbana-Champaign astronomy and physics professor Brian Fields makes a case for distant supernovae …

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Astronomers may have spotted light from colliding black holes

Caltech/R. Hurt (IPAC) Black hole collisions tend not to produce light by their very nature — you may catch gravitational waves, but that’s about it. However, scientists might have just found one of those rare instances where a collision was visible. A team using May 2019 data from both the Laser Interferometer Gravitational-wave Observatory (LIGO) …

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Astronomers think this black hole collision may have exploded with light

Enlarge / Artist’s concept of a supermassive black hole and its surrounding accretion disk of gas. Embedded within this disk are two smaller black holes, orbiting one another, that eventually collided and may have produced a detectable burst of light. Caltech/R. Hurt (IPAC) One of the most defining characteristics of a black hole is that …

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Astronomers have discovered closest black hole yet in trinary star system

Enlarge / Artist’s impression showing orbits of the objects in the HR 6819 triple system. There is an inner binary with one star (orbit in blue) and a newly discovered black hole (orbit in red), as well as a third star in a wider orbit (also in blue). ESO/L. Calçada Astronomers with the European Southern …

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Physicists identify unique signature to confirm quark-gluon plasma in universe

Computer simulation of a merger between two dense neutron stars. After the merger, a phase transition from ordinary hadronic matter (red-yellow) to quark matter (green) takes place. In the first fractions of a second of our universe’s existence, the energy density was so incredibly high that there were no protons and neutrons, just a hot …

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