Universe as a big star

[Time_Travel]

Is it possible for our Universe to be a massive star which exploded(Big Bang) and thus created our existing Universe....

[Eclogite]

No. Not possible. The characteristics of the universe at the moment of the Big Bang have practically nothing in common with the chracteristics of stars, massive or otherwise.

[Mohit Pandey]

My agruments against ur hypo are as follows--

 

1 Fine! if our universe is a star, then Hubble would not have observed an expanding universe.

To account for it, we wud have to assume the star is continously exploding till date , which is absurd to think.

 

2 If we assume it as a star, then it should have died because temperaure of CMB is about 3 K . i mean to say then how come it still has energy to propel its boundary outwards.

 

3 Then there should be a centre but no matter where we look the unierse seems to be uniform so there must not be any centre.

[Time_Travel]

My agruments against ur hypo are as follows--

 

1 Fine! if our universe is a star, then Hubble would not have observed an expanding universe.

To account for it, we wud have to assume the star is continously exploding till date , which is absurd to think.

 

2 If we assume it as a star, then it should have died because temperaure of CMB is about 3 K . i mean to say then how come it still has energy to propel its boundary outwards.

 

3 Then there should be a centre but no matter where we look the unierse seems to be uniform so there must not be any centre.

 

 

LOL,

The only reason i posted and this question was based on patterns.

Large patterns are often repetitive of there smaller versions.

I totally believe that the Universe is fractal.

[modest]

Is it possible for our Universe to be a massive star which exploded(Big Bang) and thus created our existing Universe....

 

I've read on a Big Bang faq that an expanding universe is kind of like the opposite of a collapsing star,

 

A white hole model that fits cosmological observations would have to be the time reverse of a star collapsing to form a black hole. To a good approximation, we could ignore pressure and treat it like a spherical cloud of dust with no internal forces other than gravity. Stellar collapse has been intensively studied since the seminal work of Snyder and Oppenheimer in 1939 and this simple case is well understood. It is possible to construct an exact model of stellar collapse in the absence of pressure by gluing together any FRW solution inside the spherical star and a Schwarzschild solution outside. Spacetime within the star remains homogeneous and isotropic during the collapse.

 

It follows that the time reversal of this model for a collapsing sphere of dust is indistinguishable from the FRW models if the dust sphere is larger than the observable universe. In other words, we cannot rule out the possibility that the universe is a very large white hole. Only by waiting many billions of years until the edge of the sphere comes into view could we know.

Is the Big Bang a black hole?

 

The usual answer to your question would be, I think, that the big bang is not an explosion 'into' space but rather an explosion of space. Therefore, an exploding star and an expanding universe have nothing in common in the way you're thinking. But, as the quote above shows, there are subtle caveats.

 

An star expanding under the influence of gravity alone is somewhat like a universe expanding under the influence of gravity alone.

 

~modest

[Qfwfq]

That quote is neglecting that the spacelike submanifold within the event horizon of the Schwarzschild solution is not maximally symmetric, as postulated in the FRW models of cosmology; it is hypercylindrical instead of hyperspherical. This makes the "gluing together" a bit troublesome. Maybe it could be done locally, I'm not so sure, but external time would have to be cyclic in order to do it globally.

 

I also find it amusing to talk about the edge of the sphere coming into view in the future.

[Mohit Pandey]

LOL,

The only reason i posted and this question was based on patterns.

Large patterns are often repetitive of there smaller versions.

I totally believe that the Universe is fractal.

 

sorry, i couldn't understand. could u rephrase?

[clapstyx]

I'm a novice at this but if you looked at the universe from the outside would you see the light of the big bang coming at you then darkness as that light zoomed past as the boundary of the universe?

[Time_Travel]

I'm a novice at this but if you looked at the universe from the outside would you see the light of the big bang coming at you then darkness as that light zoomed past as the boundary of the universe?

 

We can never ever stand and look outside as the Universe as there is no boundary to the observable Universe. If some one would assume that they are outside the Universe and say that as a boundary and based on it if they develop a theory it is totally bound to fail.

 

Even if we assumed we are standing outside the Universe then the light visible to you there will be past the boundary of the Universe. But that is not possible, since the light has to be within the Universe.

 

To answer your questions even though with ambiguity(Data suggests Universe is not closed but Flat):: If we assume a closed Universe light will traverse back to the starting point and then retravel again and again .

 

How is your question related to UNIVERSE AS A BIG STAR?????

Edited August 10, 2010 by Time_Travel

[modest]

I'm a novice at this but if you looked at the universe from the outside would you see the light of the big bang coming at you then darkness as that light zoomed past as the boundary of the universe?

 

I agree with Time Travel. The common metric of the universe, the FLRW metric, has no boundary under any circumstance. The idea of an 'outside' of the universe is therefore relatively meaningless in cosmic terms. You would have to define exactly what 'outside the universe' means, and using standard cosmology there could be no sensible definition.

 

The balloon analogy might be helpful.

 

~modest

[clapstyx]

I guess my question has two parts to it.

 

First question is whether the light created as part of the big bang is still in existence and Secondly where would you conceptually now have to be to see it.

 

In regards to the first question I am presuming I suppose that there was energy in the form of light produced along with all of the other variety of general produce that may or may not have cross matched their existences at a later moment to produce more advanced manifestations of matter plus energy plus quarks etc etc including life as an outcome somewhere in the equation.

 

Does light in empty space with nothing to be absorbed into just keep travelling bcause if there was only empty space before the big bang there would be nothing for it to bump into. Or does light break down over time because of something to do with the light splitting and going through two holes at once experiment and not being able to rejoin.

[Eclogite]

First question is whether the light created as part of the big bang is still in existence and Secondly where would you conceptually now have to be to see it.

Yes. It is the cosmic background radiation. You just need to be somewhere in the universe. Anywhere will do. There are no preferred locations in the universe.

[Qfwfq]

First question is whether the light created as part of the big bang is still in existence

For quite a while it was filled with a dense plasma that was opaque to EM radiation so it wouldn't be reasonable to say that "the same light" continued to propagate. After a while EM radiation could propagate, getting less and less scattered; the CMBR is considered to be essentially the radiation from when this transition occurred.

 

Secondly where would you conceptually now have to be to see it.

The CMBR can be received by a parabolic antenna anywhere pointing toward interstellar space. You don't see it of course because it isn't in the visible spectrum, it has a temperature of less than 3 Kelvin.

[Tormod]

...if there was only empty space before the big bang...

 

The problem here is that according to current models, the space-time of our universe is a result of the big bang. Thus there was no space-time before (or it was different in ways we can't measure).

 

What the others are trying to tell you is that there is no "outside", and there is no "boundary", so light from our universe can't be viewed from the "outside" since it can't escape our universe.

 

This is of course a hypothesis but very difficult to test, let alone prove, since we know nothing about what's outside the visible universe.

[Atlas shrugged]

......What the others are trying to tell you is that there is no "outside", and there is no "boundary", so light from our universe can't be viewed from the "outside" since it can't escape our universe.

 

This is of course a hypothesis but very difficult to test, let alone prove, since we know nothing about what's outside the visible universe.

 

Well just as we did not recognize until recently that we are in one galaxy out of billions , we are probably in one Universe out of billions as well.

It only stands to reason when you use the examples all around us.

 

It has been on my mind for years as I have read about the necessity of dark matter and now dark energy. It may be why we have not been able to find out much about these issues.

 

Black holes have been said to quite possibly link to other universes.

Maybe there is a great mass lurking beyond our Universe that is connected to these phenomenon.

 

Just a humble opinion.

[Turtle]

Well just as we did not recognize until recently that we are in one galaxy out of billions , we are probably in one Universe out of billions as well.

 

...

 

the prefix uni- denotes 1 (one). either you want to refer to a "oneness" of "everything" or you do not. if so, then it's a uni-verse; if not, then you must call them something else. it is really that simple. :hihi: (turtle shrugs) uni- - definition of uni- by the Free Online Dictionary, Thesaurus and Encyclopedia.

[clapstyx]

Thank You Atlas I believe I do understand. There is just something about the human mind though isnt there that it doesnt seem to accept as rational things that are endless, beginningless, undefinable, inconceivable even in some cases undeniable.