116. Wikipedia : What is a black hole?
Black hole
From Wikipedia, a free encyclopedia written in simple English for easy reading.
A black hole is an object in the Universe that has such a strong pull of gravity, even light is unable to escape it. Until recently, many astronomers did not even know if they existed, but through using telescopes and observing the Universe, they found objects with such a strong gravity, they could be nothing else except a black hole.
Black holes are made when a giant star, much bigger than our own Sun, dies. Its death is called a supernova, and is an implosion. This is where something, in this case the giant star, can no longer sustain its own weight, and all the material it is made of collapses inward, since before this, the star was in a tug of war, with gravity trying to do what it's about to, and the energy the star makes keeping it pushed out as far as it is now. When the energy runs out, gravity takes over and makes it collapse. This collapse happens so fast and so violently for the star, that the center of the star is squeezed into a very little ball, and the rest of the star bounces back and explodes outward again. The ball in the center is so densely packed together, that if you could somehow scoop only one teaspoon of material and bring it to Earth, it would be the heaviest single object on Earth. This densely packed ball is what scientists call the singularity. A black hole also has an event horizon, which is an boundary surrounding the singularity. It is the point of no return for anything travelling near the black hole. Once anything, a planet, a star, even light itself, gets within the event horizon, it cannot escape, no matter how fast it tries to go.
Since light cannot escape a black hole, it's hard to see it. The best way to know one is there is by seeing how stars, gas, and other things behave around it. With a black hole nearby, even objects as big as a star move in a different way, and a lot faster than they would if the black hole was not there. Also, if a black hole passes between us and a source of light very far away, the light will become quite distorted, much like a fun-house mirror in a circus, until the black hole moves out of the way. The light can also be magnified, like a magnifying glass, allowing scientists to see things farther away. Black holes have also been found in the middle of every major galaxy in the Universe. These are called supermassive black holes, and are the biggest black holes of all. They formed when the Universe was very young, and also helped to form all the galaxies.
Some black holes are also responsible for making quasars. When astronomers first found quasars, they thought they had found objects close to us, but after using a measuring technique called red shift, they discovered these quasars were actually very far away in the Universe. A quasar occurs when a black hole consumes all the gas surrounding it. As the gas gets close to the black hole itself, it heats up from a process called friction, and glows so brightly that this light can be seen on the other side of the Universe. It is often brighter that the whole galaxy the quasar is in.
A lot of science fiction writers use black holes in their stories, and many scientists wish to find one relatively close to Earth to study one better.
Now go to Post 115
From Wikipedia, a free encyclopedia written in simple English for easy reading.
A black hole is an object in the Universe that has such a strong pull of gravity, even light is unable to escape it. Until recently, many astronomers did not even know if they existed, but through using telescopes and observing the Universe, they found objects with such a strong gravity, they could be nothing else except a black hole.
Black holes are made when a giant star, much bigger than our own Sun, dies. Its death is called a supernova, and is an implosion. This is where something, in this case the giant star, can no longer sustain its own weight, and all the material it is made of collapses inward, since before this, the star was in a tug of war, with gravity trying to do what it's about to, and the energy the star makes keeping it pushed out as far as it is now. When the energy runs out, gravity takes over and makes it collapse. This collapse happens so fast and so violently for the star, that the center of the star is squeezed into a very little ball, and the rest of the star bounces back and explodes outward again. The ball in the center is so densely packed together, that if you could somehow scoop only one teaspoon of material and bring it to Earth, it would be the heaviest single object on Earth. This densely packed ball is what scientists call the singularity. A black hole also has an event horizon, which is an boundary surrounding the singularity. It is the point of no return for anything travelling near the black hole. Once anything, a planet, a star, even light itself, gets within the event horizon, it cannot escape, no matter how fast it tries to go.
Since light cannot escape a black hole, it's hard to see it. The best way to know one is there is by seeing how stars, gas, and other things behave around it. With a black hole nearby, even objects as big as a star move in a different way, and a lot faster than they would if the black hole was not there. Also, if a black hole passes between us and a source of light very far away, the light will become quite distorted, much like a fun-house mirror in a circus, until the black hole moves out of the way. The light can also be magnified, like a magnifying glass, allowing scientists to see things farther away. Black holes have also been found in the middle of every major galaxy in the Universe. These are called supermassive black holes, and are the biggest black holes of all. They formed when the Universe was very young, and also helped to form all the galaxies.
Some black holes are also responsible for making quasars. When astronomers first found quasars, they thought they had found objects close to us, but after using a measuring technique called red shift, they discovered these quasars were actually very far away in the Universe. A quasar occurs when a black hole consumes all the gas surrounding it. As the gas gets close to the black hole itself, it heats up from a process called friction, and glows so brightly that this light can be seen on the other side of the Universe. It is often brighter that the whole galaxy the quasar is in.
A lot of science fiction writers use black holes in their stories, and many scientists wish to find one relatively close to Earth to study one better.
Now go to Post 115
posted by Ross at 7:49 pm
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