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AstroKids › Everything in the sky › The Antennae Galaxies (NGC 4038/4039)
colliding galaxies

The Antennae Galaxies (NGC 4038/4039)

Two spiral galaxies caught in the act of colliding and merging, with long insect-antenna-like tidal tails.

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What it is

Colliding galaxies: Two galaxies in the act of merging. Every kind of thing there is →

Can you see it?

No. No telescope on Earth will show you this one; it is here to be understood, not seen. It is here because it is worth knowing about — and because leaving it out would make the sky look emptier than it is.

Worth knowing about the Antennae Galaxies

On that same scale, the Antennae Galaxies would be about 45 kilometers away. Light takes 45.0 million years to get here from the Antennae Galaxies, so what you are looking at is the Antennae Galaxies as it was 45.0 million years ago.

What it is made of
Two spiral galaxies caught in the act of colliding and merging into one.
What makes it worth knowing
Long, curving tidal tails of stars flung out by the collision, resembling insect antennae -- a preview of the future Milky Way-Andromeda collision.
The numbers
Distance from us~45 million light-years

How anyone knows this

Nobody flew a tape measure out there. Every number on this page was worked out from the ground:

Next to it

Andromeda Galaxy (M31)spiral galaxyNaked eyeTriangulum Galaxy (M33)spiral galaxyWith effortLarge Magellanic Cloudirregular galaxyNaked eyeBode's Galaxy (M81)spiral galaxyWith effortWhirlpool Galaxy (M51)spiral galaxyWith effortSombrero Galaxy (M104)spiral galaxyWith effort

Then go outside

Not this one. But the sky over your head is full of ones you can see, and the Planetarium knows which.

🌙 Plan an evening outside🌌 Everything else in the sky