Expanding Universe ...

I am sure I am not the first person to have had this thought - In fact, most of you have probably thought about this before ...

This is the definition of universe from wikipedia - It means the whole spacetime continuum in which we exist, together with all the energy and matter within it.

So, if the universe is the sum-total of everything, and includes all the space we have, how can the universe expand ? Where is it expanding into ?! How is there room for expansion and if there is room, shouldnt that have already been considered part of the universe ?

Maybe it is just that I am trying to marry my limited view of what space is with the big bang theory, but I just dont get it ... Can anybody explain this ?

Comments

Anonymous said…
In my perception, when they say the universe is expanding, it means the mean distance between two bodies increases.
Anonymous said…
The undefined borders of the universe cannot be left undecided on paper - so a new explosion, a new birth of a star has to be fit in someway or the other - so we consider it to be expanding to accomodate within itself all the new undefined sources and still be the continuum with all the energy and matter within it.

Or let's just ask Alf when he returns from Melmorque.
Ideamani said…
I still dont get it - If the volume of the universe this instant is 10 Googol cubic metres, how can this be 10.1 Googol the next day ? Where did that space of 0.1 Googol come from ? And if it already existed, how come it wasnt counted in the 10 Googol ?
Anonymous said…
1. What is claimed is that the mass is same not the voloume, so the reasoning is that the density if becoming less
2. Yes you are right about the room being expanded into is already a part of the universe - Hence the use of the term "infinity"

I feel most of them dont know what they are talking about!
Ideamani said…
Has the reduction in density been physically measured ??
Mr.Mani - Consider a cracker in space - when ignited it will burst releasing the wafers in all directions - now this is what happened to universe in beginning - once the explosion occurs - the stored energy is completely released into space - so, the total energy now in universe is very minimal when compared to what was there before the BigBang Explosion.

Now after the explosion - the whole universe took form of a large spherical loosely paked mass of stars - with greater density at the poles and minimal density at equatorial surface- since loosely paccked each body moves withits own pace in space - The Universe now is nothing but a huge Spherical - low dense mass of stars in a possible box of space -And what lies beyond the box is the Ral Mystery or The Ultimate Truth. Now this is where the Man's belief in Supernaturals/God comes into picture... Hope i m a good attempt to your question...!!

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