Olber's Paradox

[scotman]

Hi all

I have just watched TV prog 'Everything and Nothing' on BBC 4. An explanation has been given for Olber's Paradox and I understood it. Assuming that the universe is infinite with an effectively infinite number of stars has anyone calculated how long it would take before the night sky is no longer dark.

[johne1892]

I love watching prgrammes llike that and having now only just read about it I probably am not the best person to comment on it.

However, do you mean that eventually rather than seeing dark sky at night the number of stars that are generated will eventually fill every gap providing a totally white 'night sky'?

[squarebear]

But surely these stars are so far away that they will not fill the night sky totally? There are not an infinite number of stars.

[johne1892]

Sir Professor Brian Cox MBE OBE general all round good guy, said last night that our galaxy is going to collide with another in the next 6 million, billion years from now. I suppose when that happens it's not going to be very dark!

[flobadob]

6 million, or 6 billion john?

[askyourgran]

That is really interesting to know I like programmes like that. Thanks scotman I;ll look out for the programme again.

[johne1892]

It was a bit tongue in cheek as he likes his 'millions of billions' calculations.

Do I need to be accurate, were you planning something for that weekend?

[starone]

Does that mean there will be an increase in the number of stars or that we are all rapidly converging upon each other (not too rapidly of course).

[flobadob]

Just to put my mind at ease, you know.

[johne1892]

I reckon when 2 HUGE galaxies containing billions of stars collide there's going to be some fireworks...not literally of course...although that would light up the sky also!

Try to catch it on iPlayer, was really interesting. (sorry to steal your thread scotman)

[scotman]

My question is based on the premise that, over time, light from an ever increasing number of stars will reach us. Obviously these stars are further and further away and hence the light will be less intense. Also to be considered is the fact that the universe is expanding. It also seems that the rate of expansion is constantly increasing which will have an effect on this.

[nightmare]

Scotman,
what makes you think (or assume) that the universe is infinite, or that there are infinitely many stars ?
Or is your question hypothetical ?

[Davethedog]

John I have a barbecue planned that weekend, suppose i'll have to cancel.

[Davethedog]

Scotman why is it a paradox? Is it because stars keep dying as well as being born so it will never happen?

[scotman]

DtD

It is referred to as a paradox because when it was first considered the understanding of the universe suggested that the night sky should not be dark. This was essentially based on the belief that the universe was finite and fixed. If the programme is available on iPlayer it is worth watching.

[sandyRoe]

If the universe is expanding would the night sky ever be anything but dark?

[Davethedog]

Thanks I shall have a look.

[scotman]

Sandy

I think that is the conclusion that most people agree on. The expansion will more than compensate for the increasing number of stars.

[Old_Geezer]

I still do not understand why folk would assume the universe was infinite. If it started from a single point, as the "big bang" theory tells us, then it must surely have been finite at that point in time. To be finite then but infinite now it must surely have had to undergo a period where the rate of expansion was infinite. I find that difficult to believe.

[Old_Geezer]

Andromeda is heading towards us, but as galaxies are mainly open space, there ought not to be too much to get excited about.

But generally speaking everything is moving away from us as the universe's rate of expansion increases. When it is expanding faster than light you aren't going to see most of it any more.

[Davethedog]

OG Big Bang is just one theory and it still remains exactly that. I am not so well versed in the art of Astronomy, but I don't think anyone could give you an answer and say that is 100% correct. The question that is utmost is as you say, "what went bang"?