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 luminous swirl set against the deep black of space, the barred spiral galaxy IC 486 glows with a soft, ethereal light in this NASA Hubble Space Telescope image from April 13, 2026.
Astronomy
Apr 30, 2026
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Astronomers, using the Atacama Large Millimeter/submillimeter Array (ALMA), have confirmed the existence of a close quasar pair housed in a pair of merging galaxies seen when the universe was less than a billion years old, ...
A team of astrophysicists from Nanjing University and University of Bonn have demonstrated that, rather than being random, the mass of new stars born inside a star cluster is actually governed by a defined process of self-regulation. ...
Astronomy
Apr 24, 2026
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Messier 104, nicknamed the Sombrero Galaxy, is a popular target for amateur observing and astronomical research. Its recognizable extended halo, as well as a faint stellar stream, are captured in exquisite detail in this ...
Astronomy
Apr 24, 2026
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Only about 5% of the universe is composed of normal matter that we can directly observe, while the remaining 95% is widely believed to consist of dark matter and dark energy. Paradoxically, however, the nature of these dark ...
The universe has a hidden structure, and a University of Virginia professor is mapping it in 3D, using 46 million galaxies and quasars and 19 million stars. Satya Gontcho A Gontcho, an assistant professor in the Department ...
Astronomy
Apr 21, 2026
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The Dark Energy Spectroscopic Instrument (DESI) has successfully completed the largest high-resolution 3D map of the universe ever made, a major milestone in understanding the force driving cosmic expansion. The milestone ...
Astronomy
Apr 18, 2026
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European astronomers have used the Atacama Large Millimeter Array (ALMA) and the James Webb Space Telescope (JWST) to observe a recently discovered giant disk galaxy known as ADF22.1. Results of the new observations, published ...
Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have discovered a close pair of quasars, which is a result of a distant massive galaxy merger. The detection of the quasar pair was detailed in a ...
New Curtin University-led research has used a radio telescope that spans Earth to snap images that measure the immense power of jets from black holes, confirming scientists' theories of how black holes help shape the structure ...
Astronomy
Apr 16, 2026
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