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What Is A Black Hole?

Black holes were always the most dangerous thing when traveling through space in science fiction shows. What are black holes and how do they form?

A blackhole in space

Photo: NASA Marshall Space Flight Center (Flickr)

A cosmic "ghost" lurking around a distant giant black hole.

You’ve seen them in science fiction movies and television shows. But, what really is a black hole?

Creating A Black Hole

They come from stars. A black hole is what you get when a really big star uses up all its fuel.

Gravity is always trying to push all the stuff that makes up a star into its center. But as long as the star has enough nuclear fuel in its core to keep burning, it pushes back. It’s only when it runs out of fuel that everything gets crushed down into the middle of the star.

If the star is big enough, gravity just keeps squeezing and squeezing until everything that made up the star is compressed into a tiny point. And get this — the gravitational attraction of that tiny point will be so strong anything that comes too close will be sucked in, never to return!

But Why Is It Black?

Because not even light can escape. Even a passing beam of light will be pulled right in.

  • Dan Bowen

    Really guys? This is a pretty arcane, out of date, description of black holes. It sounds like what we knew in about 1960. Why is it black? How about you explain why they're NOT black. They were only black in theoretical astrophysics before they were descovered. They emit hawking radiation, which is how the stuff that fell in RETURNS OUT.

    It would be nice if you guys considered changing the tone of the show to somethign that triggers a little more active intrigue in listeners, rather than delivering a neatly wrapped fact. Give them a reason to go google for more info at the very least. Let them know that there's far more interesting stuff than you have time to tell them!

  • Christopher Egerton Chesney

    Interesting point Mr Bowen but your comment would have a little more authority if you knew how to spell ‘discovered’.  I’m not being picky – just literate.

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