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.
An astronomer at the University of Hawaiʻi at Hilo is using data from the Canada–France–Hawaiʻi Telescope (CFHT) on Maunakea to help reconstruct a slow-motion cosmic collision, one that has been unfolding for hundreds of ...
Astronomy
Apr 1, 2026
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One of the things astronomers find when they look around at galaxies is a correlation between a galaxy's mass and the mass of its supermassive black hole. Contrary to popular belief, these SMBH don't anchor their galaxies; ...
Astronomy
Mar 29, 2026
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A luminous swirl set against the deep black of space, the barred spiral galaxy IC 486 glows with a soft, ethereal light in this new NASA/ESA Hubble Space Telescope Picture of the Month image. IC 486 lies right on the edge ...
Astronomy
Mar 27, 2026
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Our Milky Way's halo of hot gas is warmer to the "south" than the "north" because of an internal combustion engine-like effect that is compressing the gas like a piston, a new study has found. Computer simulations reveal ...
Astronomy
Mar 26, 2026
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Astronomers have an answer for a long-running mystery in astrophysics: why is the growth of supermassive black holes so much lower today than in the past? A study using NASA's Chandra X-ray Observatory and other X-ray telescopes ...
Astronomy
Mar 24, 2026
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This March 16, 2026, image from NASA's Hubble Space Telescope and the James Webb Space Telescope takes a closer look at the core of Messier 101, also known as the Pinwheel Galaxy.
Astronomy
Mar 23, 2026
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Two powerful instruments of the NASA/ESA/CSA James Webb Space Telescope joined forces to create this scenic galaxy view. This spiral galaxy is named NGC 5134, and it is located 65 million light-years away in the constellation ...
Astronomy
Mar 12, 2026
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Two new studies have measured the expansion of the universe in our immediate cosmic neighborhood using a novel method that analyzes the motion of two nearby galaxy groups within their surrounding cosmic flow. The results ...
Astronomy
Mar 11, 2026
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Billions of light years away in a remote part of the universe, two neutron stars—the ultradense remnants of dead stars—collided. The catastrophic cosmic event sent light and particles, including a sudden flash of gamma rays, ...
Astronomy
Mar 10, 2026
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A new study published in Nature Astronomy indicates that the dense, star- and dark-matter–rich environments around supermassive black hole binaries pack on the order of a million solar masses into each cubic parsec. The team ...
