Galaxy

Cosma / Communication / Knowledge / Realm / Physical / Universe / Galaxy
—————————

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)

———————–

Adventures

Explore related posts on Cosma …

Milky Way Lost & Found - Have you seen the Milky Way? You may think that you have, but are you sure? Unless you live in an extremely remote area, or you’ve visited one, then you probably haven’t seen our own galaxy, the Milky Way, very well, or at all. Worse yet, you may not even realize that it’s missing. The … Continue reading Milky Way Lost & Found

———————–

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)

———————-

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)

————————–

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)

—————————

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 …

ASTRID traces 13.5 billion years of black hole...
on August 27, 2026 at 9:10 pm
In dark skies at night, distant starlight twinkles and speaks to vast cosmic histories almost as old as time itself. New data from instruments such as NASA's James Webb Space Telescope are helping astrophysicists probe deep cosmic mysteries, including the evolution of black holes and galaxies.
Milky Way's own gravity can mimic dark matter...
on August 27, 2026 at 9:00 pm
Most of the stars in our Milky Way galaxy sit neatly on a flat plane. But the space around our galaxy is much more chaotic. Rogue bands of stars called "stellar streams" orbit the Milky Way much like planets in our solar system orbit the sun.
NASA's Webb telescope rules out two new Dyson...
on August 27, 2026 at 2:00 pm
The latest Swedish-led search for technosignatures in the form of Dyson spheres has again come up empty-handed. The two latest stellar candidates in the hunt for such hypothetical extraterrestrial technology have been eliminated as Dyson spheres.
The crisis in cosmology continues: Critical...
on August 27, 2026 at 12:00 am
Doubts about the standard model of cosmology are deepening after a new study identified fundamental problems in a recent analysis that defended the conventional view that the universe is currently undergoing accelerated expansion driven by dark energy.
Using plutonium to probe the universe:...
on August 25, 2026 at 7:13 pm
Astronomers can't see dark matter directly, but they know it's there: Its gravity shapes galaxies and the large-scale structure of the cosmos. In an effort to uncover the composition of this hidden mass, a team at Lawrence Livermore National Laboratory (LLNL) is pursuing evidence of particles that exist beyond the standard model of physics.