Galaxies are gravitationally bound, large-scale astrophysical systems composed primarily of dark matter, stars, stellar remnants, gas, and dust, often embedded in extended dark matter halos. They exhibit diverse morphologies, including spiral, elliptical, and irregular types, and span mass scales from roughly 10⁷ to over 10¹² solar masses. Their internal dynamics are governed by gravity and angular momentum distribution, with baryonic components organized into disks, bulges, and halos, and frequently hosting central supermassive black holes. Galaxies are fundamental units of cosmic structure formation, participating in hierarchical assembly, mergers, and interactions within larger environments such as groups, clusters, and filaments of the cosmic web.
Astronomers have detected and traced the most distant fast radio burst ever recorded, a powerful flash of radio waves that traveled for more than 10 billion years across the cosmos before reaching Earth.
Astronomy
Oct 8, 2026
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Earth seems like a troubled place right now, but at least our cosmic surroundings appear peaceful. This is not universally true, as explosions, collisions and other dangers lurk in other places and times.
Astronomy
Oct 6, 2026
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Galaxies are enormous and hold hundreds of billions of stars. These stars form from cold, dense gas. Every large galaxy, including the Milky Way, is wrapped in a huge envelope of gas called the circumgalactic medium, or CGM. ...
Astronomy
Sep 26, 2026
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If you want to understand the origins of black holes, Yale astronomers say, you need to look beyond the centers of galaxies and start searching in the nooks and crannies. That's where you'll find the "wanderers"—black holes ...
Astronomy
Sep 23, 2026
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When the James Webb Space Telescope pointed its powerful instruments toward the early universe, scientists were surprised by what it found. At high-redshift (z) values, corresponding to less than 1 billion years after the ...
Astronomy
Sep 21, 2026
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Of all the discoveries from the James Webb Space Telescope, the multitude of Little Red Dots it has observed is among the most enigmatic. Now, simulations using the Japanese Supercomputer ATERUI III have explained the nature ...
Astronomy
Sep 17, 2026
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A new study of nine nearby galaxies has shown that actively growing supermassive black holes may contribute to, rather than prevent, star formation in their host galaxies.
Astronomy
Sep 14, 2026
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The COSMOS field, or Cosmic Evolution Survey Deep Field, is one of the most famous patches of the universe observed by astronomers. Located in the constellation Sextans, this region was photographed by the Hubble Space Telescope ...
Astronomy
Sep 12, 2026
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Astronomers have taken one of the deepest looks yet at Cloud-9, a candidate "dark galaxy," and found no trace of stars. The paper outlining this discovery was posted to the arXiv preprint server on Aug. 21.
Nearly every galaxy has a supermassive black hole. The few that don't have had theirs ejected during a galactic collision. That's because galaxies and their black holes have formed hand in hand. There is still some debate ...
Astronomy
Sep 8, 2026
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