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Look: Supermassive black holes close to Earth predicted to collide

So close, yet so far.

by Jennifer Walter
Updated: 
Originally Published: 
NASA via Giphy

MARK GARLICK/SCIENCE PHOTO LIBRARY/Science Photo Library/Getty Images

Nearly every large galaxy houses at least one supermassive black hole at its center.

But what does it mean when astronomers spot two?

Neighboring galaxy NGC 7727 has a pair of black holes at its center, leading researchers to believe it’s the byproduct of galaxies that merged a billion years ago.

ESO/L. Calçada ; N. Risinger (skysurvey.org); Digitized Sky Survey 2; VST ATLAS team; Voggel et al. Music: Azul Cobalto

It’s the closest black hole pair to Earth ever spotted, at 89 million light years away.

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And the pair is also the closest set of black holes to each other, indicating to researchers that they’ll probably collide in the future.

Writing in the journal Astronomy and Astrophysics on November 30, a team of astronomers described NGC 7727’s black hole pair for the first time.

ESO/Voggel et al.

To find the black holes, they watched as strong forces pushed and pulled on stars in the NGC 7727 galaxy.

That helped them pinpoint where the black holes were hiding.

Here’s a visualization of how that process works.

ESO/L. Calçada; VST ATLAS team; Voggel et al.

The black holes are just 1,600 light years away from each other.

For comparison, Earth is 89 million light years from NGC 7727.

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“It is the first time we find two supermassive black holes that are this close to each other, less than half the separation of the previous record holder.”

ESO/L. Calçada ; N. Risinger (skysurvey.org); Digitized Sky Survey 2; VST ATLAS team; Voggel et al. Music: Azul Cobalto

Though they’ll likely collide one day, that event has a wide time frame: sometime within the next 250 million years.

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Even if NGC 7727’s pair doesn’t collide in our lifetimes, their existence could help researchers better understand how some of the universe’s largest black holes come to be.