But today we will learn about black hole in detail. There are many things about black holes that we don’t know. But today we will talk about the black hole in such a way that can shock you.
Facts about black hole –
• Nothing can escape a black hole –
It is impossible for light to come back from inside the black hole because as we know the black hole’s gravity is very high and very powerful (even beyond our thinking). Black hole is an extremely dense object in space.
Why light easily come out from the sun?
Escape Velocity of sun – 617.7 km/sec
Speed / velocity of light – 2,99,792 km/sec
Our sun’s escape velocity is not so high that it can cross the velocity of light. So light can easily reaches on our earth or other planets from the sun.
But it can not escape a black hole because (assume) if a black hole is 1000 times massive than the sun then the escape velocity of a black hole will be 1000 x 617.7 = 6,17,700 km/sec ( means greater than the velocity of light which is 2,99,792 km/sec). This means if any object is to come out of the black hole, then its velocity should be higher than the escape velocity of the black hole. But here the speed of light is less than the escape velocity of a black hole. Therefore , no light come out of it.
It is reported by Einstein’s Theory of Relativity that our 4th dimension is time. Time is spread across the space like a sheet and all the objects present in this universe, they all make a curve in this space time. The object which curves more in this space time, the higher its escape velocity. Now how much curve an object will make in this space time depends on its gravity. And the black hole has so much gravity that even the light does not go out. That’s why nothing can escape a black hole.
•Time has no existence at the center of a black hole –
According to newton, time is absolute means time is equal for everyone. For example, if an event is happening in front of me at 5 pm, then for everyone in the universe, that event should happen at 5 pm. But does it really happen?
Suppose a bomb blast occurs, two different people are present 10 light second and 20 light second away from that bomb blast. The light emanating from that explosion will take 10 seconds to reach the first man and 20 seconds to reach the second man. But if we ask the first man when the bomb blast took place, he will say 10 seconds ago, but if we ask the same thing to the other man, he will say 20 seconds ago, then which of the two is right? Actually, both of them are correct. But if time is absolute then this could not be possible. If time was absolute then explosion would have happened at same time for both of them. So now we can say that time is not absolute but it is relative and its passing depends on the reference frame. If you are sitting in a vehicle whose speed is equal to the speed of light, then your time will be slower than others. In the same way, if you are in a field where there is too much gravity, then the time for you was slower than the rest. Now this is called time dilation.
And the black hole has so much gravity that even the light does not go out, that’s why time has existence at the center of a black hole.
•The women behind the first black hole image –
Dr. Katie Bouman, the scientist who made the first ever image of a black hole possible. Dr. Katie Bouman and her team created an algorithm that sifted through data collected from 8 radio telescopes to help construct the first ever image of a black hole. She joined the event horizon telescope (EHT) team and as one of 3 dozen computer scientists working to process telescope data from a super massive black hole located in the middle of galaxy Messier 87, 55 million light years away from us.
•If sun turned into a black hole –
Our sun is not big enough to turn into a black hole. Only those stars with higher mass (massive stars) which are over 20 times more massive than the sun turned into a black hole.