Black holes are some of the strangest things in space. A black hole sucks in anything that gets near it. Nothing can escape from a black hole—not even light.
BLACK HOLES ARE STRONG
Nothing escapes from a black hole because its gravity is so strong. Gravity is a force that pulls one thing to another. Gravity is the force that holds you down on Earth. When you jump up, Earth’s gravity pulls you right back down. Earth’s gravity also makes the Moon orbit Earth.
The more matter that is packed in a star, planet, moon, or other object, the stronger is its gravity. Gravity makes an object with more matter pull an object with less matter toward it. The Sun has a lot more matter than Earth. The Sun’s gravity pulls on Earth. It makes Earth orbit the Sun.
Matter is packed very tightly in some things and loosely in others. The matter that makes up an iron ball is packed much tighter than the matter that makes up a bag of feathers. A scientist would say that an iron ball is much denser than a bag of feathers.
A black hole is denser than anything you could imagine. A black hole could have a million times more stuff than our Sun. All of this stuff would be packed into an area smaller than a city. The force of gravity from so much stuff packed into such a small area is awesome.
WHERE DO BLACK HOLES COME FROM?
Astronomers and physicists think black holes come from dying stars. A dying star burns out and stops shining. All the stuff that makes up the star starts falling in on itself. The star gets denser and denser. If the star is big enough and has enough matter, it could get dense enough to become a black hole.
STUDYING BLACK HOLES
No one has really seen a black hole. You cannot see black holes because they do not give off any kind of light. Physicists used math to predict that black holes exist.
Astronomers look for signs of black holes. Astronomers study powerful rays coming from stars in deep space. The stars seem to be orbiting black holes. Astronomers think that black holes are sucking gas from the stars, and this makes the stars give off X rays.
Galaxies are enormous groups of stars. Astronomers think that most galaxies have huge black holes at their centers. The Hubble Space Telescope took pictures of a disk of hot gases at the center of our own Milky Way Galaxy. Astronomers think this disk is going around an enormous black hole right in the center of our galaxy.