Galaxies
14 articles about the cosmic cities of stars
Andromeda Is on a Collision Course
The Andromeda galaxy is racing toward the Milky Way at 110 km/s. In about 4.5 billion years, the two spiral galaxies will merge into one.
Dark Matter: The Invisible Architect
Galaxies shouldn't hold together based on visible mass alone. Explore how dark matter forms the cosmic scaffolding that shapes entire galaxies.
How Supermassive Black Holes Shape Galaxies
At the heart of nearly every galaxy lies a supermassive black hole. Learn how these cosmic giants influence star formation and galactic evolution.
Gravitational Lensing: Nature's Telescope
Massive galaxies can bend and magnify the light of objects behind them, acting as natural telescopes that reveal the distant universe.
Our Milky Way: A Galactic Biography
Take a journey through our home galaxy. From its spiral arms to the central bar, learn the fascinating history of the Milky Way.
When Galaxies Collide: The Cosmic Dance
Galactic collisions are slow-motion ballets spanning hundreds of millions of years. Discover what happens when two giant stellar systems merge.
The Local Group
Our galactic neighborhood contains over 80 galaxies. Explore the Local Group, including Andromeda, the Triangulum Galaxy, and dozens of dwarfs.
How Galaxy Collisions Give Birth to Stars
When galaxies collide, shockwaves ripple through giant gas clouds, triggering bursts of new star formation in spectacular fashion.
The Great Attractor
Something massive is pulling our galaxy and thousands of others toward it. What lies in the Zone of Avoidance behind the Milky Way?
Ultra-Diffuse Galaxies
Some galaxies are as large as the Milky Way but contain barely any stars. These ghostly stellar systems challenge our understanding of galaxy formation.
Galactic Cannibalism
Large galaxies grow by devouring smaller ones. The Milky Way is no exception, with stellar streams revealing past cosmic meals.
The Most Distant Galaxy Ever Found
Astronomers have spotted galaxies from when the universe was just a few hundred million years old. What do these ancient systems tell us?
Dwarf Galaxies
Small but scientifically crucial, dwarf galaxies preserve clues about the early universe and the nature of dark matter.
Ring Galaxies
Some of the most visually striking galaxies have a ring-like structure. Learn how these rare cosmic objects form through galactic collisions.