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.
A new University of Kansas survey of distant galaxies using the James Webb Space Telescope reveals never-before-seen star formation and black hole growth at "cosmic noon"—a mysterious epoch 2–3 billion years after the Big ...
Astronomy
Apr 22, 2025
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Today's rather aquatic-themed NASA/ESA Hubble Space Telescope image features the spiral galaxy Messier 77, also known as the Squid Galaxy, which sits 45 million light-years away in the constellation Cetus (The Whale).
Astronomy
Apr 18, 2025
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Astronomers from Swinburne University in Australia and elsewhere have employed the Keck II telescope to investigate the globular cluster system of an ultra-diffuse galaxy designated NGC5846_UDG1. Results of the observations, ...
Researchers using NASA's Hubble Space Telescope have discovered the magnetar called SGR 0501+4516 is traversing our galaxy from an unknown place of origin. Researchers say that this runaway magnetar is the likeliest candidate ...
Astronomy
Apr 15, 2025
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The swirling, paint-like clouds in the darkness of space in this stunning image seem surreal, like a portal to another world opening up before us. In fact, the subject of this NASA/ESA Hubble Space Telescope image is very ...
Astronomy
Apr 11, 2025
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The Andromeda galaxy is surrounded by a constellation of dwarf galaxies that are arranged in a highly lopsided manner. Analysis of cosmological simulations published in Nature Astronomy reveal that this degree of asymmetry ...
Astronomy
Apr 11, 2025
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Although we know that supermassive black holes (millions of times the mass of our sun) lurk at the center of most galaxies, their very nature makes them difficult to spot and study. In contrast to the popular idea of black ...
Astronomy
Apr 11, 2025
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Up until recently, astronomy was reliant entirely on electromagnetic waves. While that changed with the confirmation of gravitational waves in 2016, astronomers had developed fundamental frameworks in the electromagnetic ...
Astronomy
Apr 9, 2025
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A new study reports the first direct observation of merging star clusters in the nuclear region of dwarf galaxies. This detection confirms the feasibility of this formation route for nuclei in dwarf galaxies, which has long ...
Astronomy
Apr 9, 2025
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This NASA/ESA Hubble Space Telescope image features the picturesque spiral galaxy NGC 4941, which lies about 67 million light-years from Earth in the constellation Virgo (The Maiden). Because this galaxy is nearby, cosmically ...
Astronomy
Apr 9, 2025
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