Can any one explain me about the bigbang singularity

[satyaraj]

can anyone explain me about the bigbang singularity

 

[Crazy Tosser]

All matter was concentrated in a point and then time began?

 

[Naty1]

It's one concept about how our universe started.

Try reading Wikipedia under "BIG BANG"...

You can check also for things like bubble universes, parallel universes, big bounce, and quantum fluctuations for other possible perspectives on how our universe might have originated. Also check the references at the bottom of each Wikipedia article for other ideas...

 

[yuiop]

All matter was concentrated in a point and then time began?

If we define time as change, then requiring the universe to change from a state of having no time to a state of having time, requires having time in the first place for the change to happen. If I say something like there was no time before the big bang, it is self contradictory because the word 'before' is a temporal word and requires a concept of time to have any meaning. The same is true for words like ''was', 'then' and 'began'.

 

[Crazy Tosser]

If we define time as change, then requiring the universe to change from a state of having no time to a state of having time, requires having time in the first place for the change to happen. If I say something like there was no time before the big bang, it is self contradictory because the word 'before' is a temporal word and requires a concept of time to have any meaning. The same is true for words like ''was', 'then' and 'began'.

Yes, but Big Bang was the very first change of state. Even though I see your point, that nothing can "begin" if there is no time, but I think it wouldn't be wrong to say that the first process that occurred in the universe - BB - was the beginning of time, because it cannot possibly be proved that time existed before it.

 

[Fredrik]

The relevant solutions of Einstein's equation only defines times t>0. The "big bang" is the limit t→0, so every event in spacetime is after the big bang. The big bang described by general relativity is a mathematical limit, not a "process" or a "change".

 

[MeJennifer]

To comment on all those "beginning of time" thoughts, GR neither implies or refutes the idea that there is nothing on the other side of the big bang singularity.

 

[yuiop]

Yes, but Big Bang was the very first change of state. Even though I see your point, that nothing can "begin" if there is no time, but I think it wouldn't be wrong to say that the first process that occurred in the universe - BB - was the beginning of time, because it cannot possibly be proved that time existed before it.

An alternative point of view that is expounded by some quantum gravity ideas is that the universe collapsed towards a point (not quite reaching it) and then rebounded to what we see today. In those theories, if we consider the time when the rebound occurred to be the big bang, then there is a concept of time before the big bang from that point of view. However, I should point out that there is not yet a generally accepted quantum theory of gravity. I think it might also be fair to say that there is no universally accepted description of what happened exactly at the time of the big bang or just before it, although there seems to be an accepted view of what happened some billionths of a second after the big bang.

 

[Naty1]

then requiring the universe to change from a state of having no time to a state of having time, requires having time in the first place for the change to happen.

While that IS "logical" it is unproven...Photons have no "time" for example...they don't age..

No one knows among time,energy,mass,space if one is fundamental and the other emergent...We do not know quite what the big bang is...Neither relativity nor quantum theory works at a big bang singularity...as MeJennifer posted, neither says anything directly about it...on the other hand, some theory suggests inside a black hole, space is replaced by time so the black hole singularity is located in time not space!...equally crazy, but possible, I guess...

 

[Fredrik]

To comment on all those "beginning of time" thoughts, GR neither implies or refutes the idea that there is nothing on the other side of the big bang singularity.

That comment is a bit strange. No theory can imply or refute an idea. What you said is true, but it's true in exactly the same way that it's true that Newton's theory of gravity doesn't imply or refute the idea that stuff will be falling away from massive objects tomorrow.

 

[yuiop]

... on the other hand, some theory suggests inside a black hole, space is replaced by time so the black hole singularity is located in time not space!...equally crazy, but possible, I guess...

That is the Kruskal-Szekeres description of time and space within a black hole. There is an alternative description that is slightly less crazy, yet still in agreement with General Relativity.

Ahem..cough..cough.. :shy: