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♪
NARRATOR: Now, while a lot of smaller black holes enjoy spending time by themselves,

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others can be a bit more ... social!

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To be specific, black holes often love to dance
with other objects in the universe.

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Sometimes, the dance begins with two stars,
long before the black hole is even part of the picture.

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Then, one day, one of the two stars goes supernova, and …

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pop! The dance continues, but with a new partner.

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Other times, when another massive object – like a star –

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happens to pass by a black hole, it,
and the black hole, can't help but dance together!

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In either case, the black hole could even pull stuff off of
its new friend to make a fancy accretion disk.

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Look at it go!

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And while these first two black holes have been paired up with stars,

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there are a quite a few other potential dance partners out there in the universe.

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Smaller black holes have a great time dancing with low-mass stars, high-mass stars,
white dwarfs, neutron stars,

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unicorns … wait, what?

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[record scratch, music stops]

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NARRATOR: Off you go, then! Shoo!

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[unicorn whinnies and flies off]

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NARRATOR: Ahem. Anyway, they can also dance with other black holes,
including really, really big ones.

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And sometimes, when they're dancing with a giant star,
that giant star can go supernova,

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eventually producing another neutron star, or ... 
voila! A second black hole!

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And, if either of those two get a bit too close to the other black hole ...

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You could get a new, larger, single black hole!

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By the way, did you hear that? When two black holes collide,
they also produce a ton of energy as ripples in space-time,

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and, if we have the right tools, we can actually listen to them! Amazing.

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Well, there you have it! Now grab your telescopes,
get out there, and dance the night away!