A black hole is an area in space with a powerful gravitational pull that makes it impossible for light to get out. The gravity is this small because of the excess matter crammed into a small space. This happens for various reasons, one of which is a dying star. Since light cannot get out, black holes are invisible to the eyes, but there are special tools which can be used to see them with space telescopes. Using these tools, it is easy to identify the difference between normal stars and those that are close to becoming black holes.
There are varieties in the size of black holes. They can be small or big, and scientists believe there are black holes that are the size of an atom. However, the tiny size of these black holes does not affect their mass that could be up to that of a mountain. Stellar is another type of black hole. This has a mass that could be 20 times above that of the sun, and many of these stellar black holes can be found in the earth’s galaxy. The largest types of black holes have the mass that exceeds that of one million suns. They are known as supermassive and scientists have discovered that there is a supermassive black hole at the centre of every galaxy. In the Milky Way, the supermassive black hole is known as Sagittarius A, and its mass is equal to that of 4 million suns.
According to scientists, the smallest black holes are as old as the universe itself. Stellar black holes, on the other hand, are formed from the collapse of a big star. This causes a supernova as the star explodes, blasting fragments of it into space. Supermassive holes, on the other hand, are as old as the galaxy where they exist.
One of the things people wonder about is how it can be seen. Since this strong gravity area sucks light into it, scientists notice the effects of the gravity on the gas and stars around it. By studying the stars, scientists can discover if they are orbiting a hole or flying around. High energy light is produced when a star and black hole are close together, and telescopes and satellites pick up this light.
The earth is not at risk of falling into a black hole. There is a black hole close enough to the earth’s solar system. However, if a black hole should replace the sun which cannot happen because the sun is not big enough to turn into a black hole, the earth will continue to revolve around the hole as it will have the same mass as the sun.