# Discussion about Black holes in outer space

Hi, Partners. Here I would like to discuss about the discovery of black holes. I am very passionate about this and I am eager to know that what would happen when something gets in a black hole. Theories say that inside a black there is no mass. Even photons cannot pass through it. What are your views? How do you feel about it?

Note by Bijoyan Das
5 years, 9 months ago

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If we take classical physics only into account then anybody can pass right on through into a black hole. Eventually as you get to the center things will become unpleasant, but for large black holes you can go right through the event horizon (the 'surface of the black hole') and everything will be perfectly fine for a while.

If we add quantum mechanics to the mix, then it was long argued that still nothing strange would happen to an observer falling through the event horizon. However, there has been a resurgence of debate on the effect of quantum mechanics in the physics community in the past year as there was a suggestion that a 'firewall' will form at the horizon, thereby cooking an observer falling into the black hole. The firewall issue is pointing out some inconsistencies in our physics assumptions and is proof that even when things look decided, they rarely are.

Staff - 5 years, 9 months ago

Not sure but I can think of two reasons why even photons (fastest thing in the universe) can't escape from a black hole:

1) The gravitational pull of the black hole is so strong that it is able to pull the photon towards it, or 2) Space-time around the black hole is distorted to the point that any moving thing will always follow a curved path leading back to the black hole (i think this region's boundary is defined as an event horizon, since any event happening in this region will be impossible to observe by someone outside the region)

- 5 years, 9 months ago

I just want to extend it a little of what i feel and is based on my calculations. A black hole is formed after a star 4 times(approx.) the size of our sun dies (which we all know). We know escape velocity of a body is given by $$sqrt({2ar}$$),where a is the acceleration due to gravity of the object,and 'r' the radius of the object, and 'a' depends on mass of the object, so in case of a black hole the mass is unimaginably large ,therefore its escape velocity turns out to be also very very large, in fact larger than 'c', hence I feel that just like an ordinary star, a black hole too emits light but it appears black because light can't cross the gravitational field of the black hole and hence the name "BLACK HOLE".

- 5 years, 9 months ago

gravitational pull occurs due to distortion of space-time by massive objects.(I think)

- 5 years, 9 months ago

What happen if one black hole was to form close enough to another so that each other's event horizon's could interact? Could the larger pull in the other? Are there even sizes to black holes?

- 5 years, 9 months ago

Hey You know what , a cluster of black holes is found in the universe .Cant b precise about the location , google it! It is found that the light travelling from that point is about 14 billion years old .And the big bang is said to have occur 14 billoin years ago ..So we can come to a solution that the cluster is as old as the universe ..Queer yet interesting.

- 5 years, 9 months ago

is black holes are there in our galaxy?

- 5 years, 9 months ago

actually there is one super massive black hole which causes the sun and other stars to revolve around it. its the nucleus of our galaxy......

- 5 years, 9 months ago

yes

- 5 years, 9 months ago

Of course .A lot of them

- 5 years, 9 months ago

The concept of an object from which light could not escape (e.g., black hole) was originally proposed by Pierre Simon Laplace in 1795. Using Newton's Theory of Gravity, Laplace calculated that if an object were compressed into a small enough radius, then the escape velocity of that object would be faster than the speed of light.

- 5 years, 9 months ago

A question... is the timeline inside or near a black hole different from earth? time travels in same speed or different. I read somewhere in a book long ago that the time there moves so slower...

- 5 years, 9 months ago

yes

- 5 years, 9 months ago

Right on bro. Time Moves slower inside a blackhole. In fact, Inside a black hole, time does not even exist

- 5 years, 9 months ago

Actually, it depends on who is keeping time. In our everyday world, you keep time with your clock and I keep time with my clock. We can relate our times and synchronize our clocks by passing light signals back and forth, for example. Hence everybody has a valid time that we can relate to everybody else's time. If, however I fall into a black hole and you stay outside, then this mapping breaks down (think of it as that physically we can't send light signals to synchronize). So while it's not quite right to say that time doesn't exist inside a black hole, it is true that the time for people inside the hole is not simply related to the time for people remaining outside.

Staff - 5 years, 9 months ago

i also read somewhere that if we move to speed of light then time tends to zero..... so according to this radio waves should not have time in them.... pls help me understand this..

- 5 years, 9 months ago

how can u say that time does not exist???

- 5 years, 9 months ago

it means that if we are twin, then you decided to go travelling in space at the speed of light and you started 8 am at your watch then ... you return on earth at 9 am ...then you might find out that i have been long gone and your currently talking to my great grand children ...

- 5 years, 9 months ago

The Theory of Relativity(TOR) is used for massive stuffs while the Quantum Mechanics(QM) for tiny ones. But the black hole is both tiny and massive so both the theories need to be used to explain them. But TOR and QM are like huge enemies. They cannot be used together because the result that scientists get when they try to use them together is infinity!!! But the M-Theory is coming up to explain these. PHYSICS IS GREAT!!!!!!!!!!

- 5 years, 9 months ago

I will be going into a Black Hole tonight ; but never mind ; I will have returned by yesterday morning ..

- 5 years, 9 months ago

Ooh! Black holes are fun :) Particularly discussing whether or not there exists a singularity in space time at a black hole, since if there does, this could have enormous consequences, I read "The universe in a nutshell" which gives lots of good info, I cant remember most of it now though. Reading about string theory now though, which tries to say that such a singularity would be impossible, since anything smaller then the Planck length in this way doesn't really make physical sense, therefore there is a minimum limit. An interesting theory I heard was about information loss from black holes, so once a particle goes into the black hole, it is essentially lost, so that the universe loses the information contained within the particle. The schrodinger equation breaks down, and information for related particles outside the black hole is lost, so determinism breaks down. In my opinion this is one of the most interesting aspects of black holes as it has such a fundamental consequence if its true, or if it isnt.

- 5 years, 9 months ago

Coincedentally few days back I was reading "The Brief History of Time", Its a great book .The language is simple enough for anyone to understand space-time and black holes.

- 5 years, 9 months ago

any body can pass through black hole?

- 5 years, 9 months ago

I'll tell you after 2 days. I and David are going to a vacation in our backyard black hole and are coming back after two days. If we do come back, you've your answer.

Actually, I don't think you can make concrete conclusions on black holes. I attended an interactive lecture of Sir Roger Penrose, where someone asked him about black holes. He said, "I'll not comment on this one because the last thing I want in this age is, to get involved in a black hole controversy!"

- 5 years, 9 months ago

I wish I had a backyard black hole. Although you can make in a laboratory fluid systems where the dynamics of sound waves in the fluid is just like the dynamics of light and matter near a black hole. (Think of a fluid flowing in a pipe. If you squeeze the pipe enough, the speed of the fluid can be greater than the speed of sound. Boom, you get an 'horizon' from which no sound wave can escape).

Staff - 5 years, 9 months ago

it should be able to attract all masses from every dimension, like in time... Is it possible dat it attracts mass from past/future ?? ,

- 5 years, 9 months ago

What blackhole receives is emitted through White hole, in parallel universe

- 5 years, 9 months ago

i think that they are just like recycle bin of universe. its true that due to large gravitational field nothing can escape from it. speed of time becomes 0 inside a black hole or might they work as time warp

- 5 years, 9 months ago