wo spiral galaxies appear as light colored swirls on either side of an orange star.


Astronomers Look into the Past of Local Dwarf Galaxies

A combination of simulations and observations indicates that galaxies like the Large Magellanic Cloud control when punier dwarfs plunge into large galaxies.

Andromeda's halo and 43 quasars


Astronomers Map Andromeda’s Halo

Astronomers have observed 43 quasars in back of our sister galaxy, Andromeda, using the distant beacons to map its halo of hot gas.

Rotation of Andromeda Galaxy


New Study Pushes Back Milky Way’s Dust-up with Andromeda

By tracing stars in other galaxies, the Gaia satellite has helped astronomers understand the relative motions of the Milky Way's galactic siblings.


Andromeda Collided with Galactic Sibling Billions of Years Ago

A new study says our neighbor galaxy’s big stellar halo and stellar evolution are due to a major collision that ended 2 billion years ago.

Deep Sky

Resolving Andromeda — How to See Stars 2.5 Million Light-Years Away

At 2.5 million light-years away, you might think it's impossible to see individual stars in the Andromeda Galaxy. Let its largest star cloud, NGC 206, show you the way.

Binocular basics

Explore the Night with Bob King

Watch Andromeda Galaxy Blossom in Binoculars

How much can you see of the Andromeda Galaxy system with just a pair of binoculars? Turns out a lot!

Andromeda's halo


Spotting Andromeda Galaxy’s Giant Halo

Astronomers have detected a massive yet elusive nimbus of hot gas surrounding Andromeda Galaxy.

PHAT field for M31


Charting the Andromeda Galaxy

The Hubble Space Telescope has turned its ultraviolet, visible-light, and near-infrared eyes to the queen of galaxies, M31, capturing the biggest and sharpest image yet of our neighbor.


(Really) Cool View of Andromeda Galaxy

Nearing the end of its mission, ESA's Herschel Space Observatory has delivered a highly detailed map of extremely cold gas and dust in the iconic Andromeda Galaxy.


Andromeda Galaxy’s Odd Double Core

A new study simulating stars as they orbit a black hole might provide the best explanation for how our nearest spiral galaxy neighbor grew its lopsided nucleus.

Andromeda Galaxy

Science-based Q&A

Is it true that Andromeda Galaxy is moving toward us?

Is it true that the Andromeda Galaxy is blueshifted and moving toward us? How can this happen in an expanding universe? The Andromeda Galaxy (M31) is indeed approaching us, by about 300 kilometers (190 miles) per second measured with respect to the Sun. If you subtract the Sun’s orbital motion…

Andromeda Galaxy

Andromeda's Black Hole Surrounded by Young Stars

The Andromeda Galaxy, about 2.5 million light-years away, contains a black hole with the mass of 140 million Suns that has a strange disk (blue) of young hot stars within 1/2 light-year of it.John Kormendy (University of Texas at Austin) / Ralf Bender (University Observatory, Munich, Germany) It's no secret…