Black Holes

From ForcaWiki, the simple encyclopedia

Think about the drain in your bathtub. When you pull the plug, the water swirls toward it and disappears, and once it goes down it does not come back up. A black hole is a little like a drain in space, except it does not only pull water. It pulls in anything that drifts too close: dust, gas, whole Stars, and even light itself.

What actually makes a black hole?

A star is a gigantic ball of burning gas, and for millions of years it stays puffed up because the heat pushing outward balances the Gravity pulling inward. When a really heavy star finally runs out of fuel, the outward push stops and gravity wins. The star collapses, falling in on itself in a fraction of a second, like a tent flattening the instant you yank out the poles. If the star was heavy enough, all of that material gets crushed into an incredibly tiny point, and the pull around it becomes stronger than anything else in the universe. That is a black hole.

Why can't we see one?

You can see your bike because light bounces off it and travels back to your eyes. Around a black hole, gravity is so strong that once light crosses a certain line it can never climb back out. Scientists call that line the "event horizon," which is really just a fancy name for the point of no return. Nothing that crosses it, not even a beam of light, can escape. With no light coming back to your eyes, you see nothing at all, which is why it looks like a perfectly black hole cut out of space.

Could a black hole swallow the Earth?

You can relax. Black holes do not roam around the galaxy hunting for planets to eat. They mostly stay put, and something is only in danger if it wanders very close, the way a leaf is only in trouble if it floats right up to the bathtub drain. The nearest known black hole is so far away that even our fastest spacecraft would need millions of years to reach it. Earth is completely safe.

Fun facts

• To turn the Earth into a black hole, you would have to squeeze the entire planet down to the size of a marble. Good luck with that.
• In 2019, scientists revealed the first real image of a black hole, in a galaxy called M87. It looks like a glowing orange ring wrapped around a dark center.
• Our own galaxy, the Milky Way, has a giant black hole at its center that weighs about four million times as much as the Sun. It sits tens of thousands of light years away, so it is no threat to us.