Name: This Black Hole Is So Close You Can “See” It, Here’s How
Uploaded: 2020-08-10T19:30:17.000Z
Duration: 3 min 42 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

When I was a kid, a few things kept me up at night.

Adverbs of manner

Namely the Bermuda Triangle, quicksand, and black holes.

Turns out, as an adult these things are way less of a day-to-day problem than I thought

Now I'm lying awake at night all over again, because astronomers have just found the closest

black hole to us yet, and they suggest there could be even more lurking out there in the universe.

Finding black holes is tricky, what with them capturing everything that strays too close,

They are 'unseeable' by their very nature, and only the effects of their intense gravity

They are the sarlaccs of space, the insatiable invisible maw of destruction.

So, it's a bit ironic that the researchers who found this nearby black hole weren't

The astronomers were looking at what they thought was a double star system called HR

Not the most fear-inducing name I've ever heard of, but just wait.

This pair of stars is close enough that it can be seen from the Southern Hemisphere without

any optical aids on a dark and clear night.

While observing the stars, the astronomers noticed that what they were actually seeing

The inner star appeared to orbit something once every 40 days, while the outer star orbited

the pair much farther away, I assume out of a sense of self-preservation.

So, how did the researchers know the object the inner star was orbiting was a black hole?

Well, whatever it was orbiting was invisible, which is a pretty strong clue.

But they could also use the inner star's orbit to determine the mass of its invisible

partner, which they determined had a mass about four times that of our Sun.

Based on those two pieces of information, the third member of this stellar tango is

This makes HR 6819 the first star system with a black hole that can be seen with the naked eye.

Perhaps the most intriguing thing, or worrying thing depending on how paranoid you are, is

Up until now, we've only spotted a few dozen black holes in our galaxy, and usually they

stick out because of how violently they interact with their surroundings.

They're siphoning off matter from companion stars and blasting x-rays out into space.

By contrast, the black hole hidden in HR 6819 doesn't seem to be doing much of anything,

It's just quietly waltzing with its partners, minding its own business.

But it's very existence hints at much more.

If we found one this close by and this easily, then in all likelihood there are many more

black holes just like it throughout our galaxy.

We've long suspected that throughout the history of the Milky Way many stars must have

collapsed into themselves, and discovering this quiet black hole could explain why we

The astronomers who led this study estimate that there must be hundreds of millions of

So, should you be terrified that there are scores of black holes around every corner

waiting to get you like an army of darkness?

For perspective, the nearest star to our solar system is a little over four light years away.

If anything, discovering this quiet black hole opens up opportunities to understand

how large stars evolve or how three body systems can trigger black hole mergers and stellar

And besides, if a black hole were to get you… you'd never see it coming.

Do you devour any information about black holes that comes within your reach?

Then check out our playlist on black holes here!

Make sure to subscribe for more videos like this, and as always, thanks for watching.