Exploring black holes....
Black holes
we are living in a world where there is always something to learn and our learning must not be confined to the boundaries of earth. In outer space there are various systems, bodies and processes to know about....It's interesting to know that space is not really what it seems from the earth.Here is something about black holes to make you more familiar with them...
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| structure of a blackhole |
Black holes are regions in space-time where the gravitational force is so strong that even no electromagnetic radiation including light can not escape. In other words we can say these are regions where time and space are twisted too much. The existence of black holes was first predicted by sir Einstien's theory of general relativity published in 1915.
Structure
Modern physics don't have much information about the structure of a black hole cause laws of physics do not work inside the boundaries of black hole due to it's very high gravitational force.These are some of the parts of a black hole.
1》Singularity÷ This is the point where all the mass of black hole is compressed. This point has zero volume and infinite density.
2》Event horizon÷ This is the boundary of a black hole from where even can not escape.
3》Schwarzschild radius÷ This is the radius of event horizon. R = 2GM/c square
Formation
Black holes are formed in various ways but generally they are formed by dying star which is very big in size. Size plays a crucial role in the formation of black hole. When a big star is in it's last stage it explodes with a supernova explosion and expells out it's outer parts in space and it's core is left behind. Then the gravitational force of star compresses the core causing it to collapse under it's own weight. The mass of core is collasped into a point called singularity which later acts as the center of black hole.
Types of black hole
According to the theory of general relativity there are three types black hole.
1)Stellar÷ These are formed when a massive star dies and collapses under its own wieght.e.g. Cygnus X-1 discovered in 1965.
2)Supermassive÷ These are very heavy and have mass equivalent to billions of suns. These are generally found in the centres of most galaxies, one bieng present at the centre of our own galxy named Sagittarius A.
3)Miniature÷ No miniature black hole has been discovered yet but scientists propose that these were formed during the early days of universe.
Growth
As the black holes aquire more and more matter from the sorrounding they continue to grow in size. Black hole may also merge with stars and black hole to grow larger.
Curious questions and thier and answers.......
1》Why massive stars form black hole at the end of their of life?
Ans: During the normal lifespan of the star it tries to maintain the balance between gravity and pressure both of which work opposite to each other as the gravity pulls things inward while the pressure pushes outward. The pressure required to balance gravity comes from the nucler reactions going inside the core of star. Throughout it's whole life it is stable, but when it's nuclear fuel is exhausted then pressure is overthrown by gravity. As a result the core is compressed to form a black hole. Due to the very big size of core the electron-electron repulsions within the star can not balance very powerful gravity.
2》Why don't small stars form black hole?
Ans:This type of star is called 'white dwarf'. When stars are no more left with nuclear fuel to balance its gravitational force then the electron- electron repulsions inside the star create pressure required balance the gravitational force. Thus, the slowly cools down and vanished in the darkness of space.
3》What will happen if our sun turns into a black hole?
Ans:First of all it is not possible at all cause the size of the sun is very small to form a black hole. If we suppose then also the planets revolving around the sun are not going to be affected and they will continue to revolve in their orbits. They will need to be close enough (nearly 6-7 miles from the center of black hole) to get affected by it.
4》What interesting thing is revealed about spinning black holes?
Ans:This kind of blackhole is also called charged black hole. This is hypothetically possible that the other end of this black hole opens into another spacetime which possibly may support time travel.
☆ Thank you ☆
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