Galaxy

Cosma / Communication / Knowledge / Realm / Physical / Universe / Galaxy
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galaxy : any of the large groups of stars and associated matter that are found throughout the universe — Merriam-Webster See also OneLook

Thesaurus

Roget’s II (Thesaurus.com), Merriam-Webster Thesaurus, Visuwords

Encyclopedia

Galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. Galaxies contain varying amounts of star systems, star clusters and types of interstellar clouds. In between these objects is a sparse interstellar medium of gas, dust, and cosmic rays. Dark matter appears to account for around 90% of the mass of most galaxies. — Wikipedia

Galaxy (Encyclopædia Britannica)

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Inspiration

Astrum (YouTube Channel)
Astrum (Facebook Page)

Hubble Skymap puts the night sky at your fingertips any time of day. Roam the Milky Way to find a selection of stars and nebulae as seen by Hubble. To explore the skymap, scroll, double click, or pinch/swipe to zoom in and out. Roll over an icon to see the object, click to zero in, and click again for a detailed view and a description. Drag the map to navigate. — Hubble Skymap (NASA Science)

Hubble Skymap (NASA Science)

Hubble’s Galaxies is a collection of galaxy images from the Hubble Space Telescope — Hubble’s Galaxies

Hubble’s Galaxies (NASA Science)

Big Idea 9: There are Hundreds of Billions of Galaxies in the Universe (Big Ideas in Astronomy, International Astronomical Union)

Talks about Galaxies (TED: Ideas Worth Spreading)
Articles about Galaxies (Big Think)

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Innovation

Science

Galactic Astronomy is the study of the Milky Way galaxy and all its contents.The Milky Way galaxy, where the Solar System is located, is in many ways the best-studied galaxy, although important parts of it are obscured from view in visible wavelengths by regions of cosmic dust. The development of radio astronomy, infrared astronomy and submillimetre astronomy in the 20th century allowed the gas and dust of the Milky Way to be mapped for the first time. — Wikipedia

Extragalactic Astronomy is the branch of astronomy concerned with objects outside the Milky Way galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy. The closest objects in extragalactic astronomy include the galaxies of the Local Group, which are close enough to allow very detailed analyses of their contents (e.g. supernova remnants, stellar associations). — Wikipedia

Astronomic (YouTube Channel)
Astronomic (Facebook)

Galaxies (NASA Science)
What are Galaxies? (NASA Science)
Galaxies (Imagine the Universe, NASA Goddard Space Flight Center)

Galaxy Videos (ViewSpace, Space Telescope Science Institute)
Galaxy Evolution Videos (ViewSpace, Space Telescope Science Institute)
Galaxy Structure Videos (ViewSpace, Space Telescope Science Institute)

Galaxies (Lunar & Planetary Institute)
Galaxies and Cosmology (Max Planck Institute for Astronomy)

Galaxies (Eric Weisstein’s World of Astronomy, Wolfram Research)
Galactic Astronomy (Eric Weisstein’s World of Astronomy, Wolfram Research)

Galaxies (Wolfram Alpha)

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Preservation

History

Historical Overview of the Discovery of Galaxies (Earth Guide)
Historical Overview of the Discovery of Galaxies (Introduction to Astronomy, Wolfgang H. Berger, UC San Diego)
Timeline of Knowledge about Galaxies, Clusters of Galaxies … (Wikipedia)

Library

DDC: 523.112 Galaxies (Library Thing)
Subject: Galaxies (Library Thing)

Subject: Galaxies (Open Library)

LCC: QB 856 Galaxies (Library of Congress)

Subject: Galaxies (WorldCat)

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Participation

Education

Science Education Videos (NASA Goddard Space Flight Center, YouTube Playlist)
NASA Goddard Space Flight Center (Official Website)

What is a Galaxy? (Space Place, NASA)
Galaxies (Imagine the Universe, NASA Goddard Space Flight Center)

Galaxies (Science Trek)
Galaxies (Cosmos4Kids)
Galaxies (Space Scoop)

Galaxies (Astronomy Center, ComPADRE)

Galaxies, Part 1 (Crash Course Astronomy, YouTube Video)
Galaxies, Part 2 (Crash Course Astronomy, YouTube Video)

MERLOT: Multimedia Educational Resource for Learning and Online Teaching
OER Commons: Open Educational Resources

Community

Organization

International Astronomical Union Division J – Galaxies and Cosmology

News

Galaxies (Nova Research Highlights, American Astronomical Society)

Galaxies (EurekaAlert, AAAS)
Galaxies (JSTOR)

Galaxies (Sky & Telescope, AAS)
Galaxies (Astronomy Magazine)

Galaxies (Science Daily)
Galaxies (Phys.org)

Recent News from Phys.org …

Hubble spies faint irregular galaxy ESO 490-017
on May 27, 2026 at 6:00 pm
This NASA Hubble Space Telescope image features the dwarf irregular galaxy ESO 490-017, roughly 12,000 light-years in diameter and some 23 million light-years away in the constellation Canis Major. The galaxy's low surface brightness makes it appear as a faint, starry swarm behind brighter foreground stars that are easily recognized by their diffraction spikes. Numerous red, orange, and beige dots are distant galaxies peppering the black background, many exhibiting distinct spiral structure.
Could aliens ever visit Earth? An aerospace...
on May 27, 2026 at 2:01 pm
On May 22, 2026, the Pentagon released a second batch of previously classified photos and videos showing what appear to be unexplained flying objects. These file dumps were the culmination of a process that was set in motion back in July 2023, when a group of government whistleblowers testified before Congress that the U.S. government was secretly in possession of extraterrestrial spacecraft and suspected alien body parts.
Astrophysicists strike black gold with treasure...
on May 26, 2026 at 5:20 pm
Researchers from the University of Glasgow's Institute for Gravitational Research are celebrating the publication of a vast new treasure trove of gravitational wave detections, hailed as a milestone marking the coming of age of gravitational astronomy.
Just 1.2 billion years after the Big Bang,...
on May 26, 2026 at 1:00 pm
A large protocluster of galaxies that existed 12.6 billion years ago, first discovered with the Subaru Telescope, has been examined in detail using the James Webb Space Telescope (JWST). The study found that galaxies in crowded regions are more extended than similar galaxies in less dense environments. The results, published in The Astrophysical Journal Letters , show that even when the universe was only 1.2 billion years old, environment was already influencing how galaxies grow.
How Mars can help us understand 'marginal'...
on May 26, 2026 at 11:00 am
Mars holds a special place in the solar system. It represents marginal habitability. This means it transitioned from warm and wet and potentially hospitable, to cold and dry and inhospitable.