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.
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 ...
For this month's ESA/Hubble Picture of the Month, NASA/ESA's Hubble Space Telescope is joined by ESA's Euclid to create a new view of the most visually intricate remnants of a dying star: the Cat's Eye Nebula, also known ...
Astronomy
Mar 3, 2026
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It is one of the most famous questions in science, and it was asked, as legend has it, over lunch. Enrico Fermi, the physicist who helped build the first nuclear reactor and whose name graces a unit of length so small it ...
Astrobiology
Mar 2, 2026
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NGC 941 is located approximately 55 million light-years away in the constellation Cetus. This faint galaxy is classified as an intermediate spiral, exhibiting characteristics between a barred spiral with a central bar and ...
Astronomy
Feb 26, 2026
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An international team of astronomers has employed the Atacama Large Millimeter/submillimeter Array (ALMA) to investigate molecular gas in a nearby galaxy known as NGC 1387. Results of the observational campaign, published ...
We have known for several decades that the universe is expanding. Scientists use multiple techniques to measure the present-day expansion rate of the universe, known as the Hubble constant. These methods are internally consistent ...
Astronomy
Feb 24, 2026
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An international team of scientists led by the Institute of Cosmos Sciences at the University of Barcelona (ICCUB) and the Institute of Space Studies of Catalonia (IEEC) has presented REGALADE, an unprecedented catalog covering ...
Astronomy
Feb 20, 2026
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125
That the universe is expanding has been known for almost a hundred years now, but how fast? The exact rate of that expansion remains hotly debated, even challenging the standard model of cosmology. A research team at the ...
Astronomy
Feb 19, 2026
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