We know that earth is a part of Milky Way galaxy. In space there are many other galaxies and many planets in those galaxies. Space remained a misery and many questions are remaining unanswered. We all believe that this universe came into existence according to big bang theory. According to this theory a large solid mass exploded and galaxies are formed.
Man has researched a lot and researches are still continuing to reveal the truth of origin of this universe. We are all heard about black holes. What are these black holes?
We all think that it is large hole in which substances falling into it don’t come back. Let’s see
What is a black hole?
Black hole got its name because of the fact that it absorbs all the substance passing near through it and even light cannot escape from it. According to the theory of relativity black holes are generated by the deformation of compact amount of mass. Black hole is a theoretical fact and its existence has been proved only theoretically. This is because nothing returns from a black hole and we cannot study about it. When photographs of space are taken with telescopes the deformation observed reveals that black holes really exist.
Suppose we through a stone by standing on the earth’s surface. It will come back due to earth’s gravitational force. And if we through a stone from the surface of moon it will also come back. But the distance travelled will be more in the moon since the gravitational force is less on moon. This shows that gravitational force is related to mass. Now think about black hole. It can absorb even light passing near through it, then what will be its mass. So black hole is an immensely massed and denser substance.
How black holes are formed?
Black holes are formed when stars run out of fuel. When a star stops burning it cannot withstand the gravitational pull of itself and it shrinks into itself and forms a denser, massed black hole.
Why a substance cannot escape from a black hole?
Black holes are immensely large bodies and therefore it has large gravitational force. So in order to escape from a black hole the escape velocity should be large. But speed greater than velocity of light is not possible to attain. That is why substances don’t escape from black hole. Black holes are found in the centre of a galaxy. This means that black hole is the end of the galaxy.
What will happen to the thing that has fallen into a black hole?
Suppose that you are going a journey to the black hole. You get into a space ship and started journey towards the black hole. Upon approaching black hole you will feel denser and heavier. Let your feet is nearer than your head towards the black hole then what will happen. Your feet will get stretched and it will be ripped off. Finally the whole body will be ripped off. This will be the situation upon reaching a black hole.
Do all stars will become a black hole?
Now we will be thinking that what will happen if sun becomes a black hole? No don’t worry about it. All stars don’t changes into black hole. Stars having considerable mass will change into black holes. Sun will not become a black hole. When it is completely run out of fuel it will become a white dwarf.
How to escape from a black hole?
Substances that are fallen into black hole have no return. But black hole has a radius or a horizon. A black hole can attract only substances that have passed that horizon. So keep away from that horizon is the only way to escape from a black hole. Another fact is that black holes evaporate and when completely evaporated there will be no black hole. Also in order to cross the horizon an infinite time is required so if you reach the centre of black hole by passing infinite time the black hole may have been gone.