The Sun is surrounded by millions of binary stars!

The Sun swings around its galactic orbit alone, a solo voyage through space.

But for half the stars in the Milky Way that's not the case. They exist with a companion, a duo traveling the cosmos together. Bound by gravity, these binary stars come in a bewildering variety of characteristics and in many ways are the key to understanding the cosmos.

And now we know there are well over a million of them within about 3,000 light years of the Sun.

That's due to the Gaia observatory and a dedicated t...