[andy054 (OP)]

Why is there a universe?

If there was a big bang, what came before it, and before that, and so on?

Surly nothing should be, but it is, why?   

[Vern]

I am one of those who suspect there was no Big Bang; so for me the universe always existed. As to why it exists; who knows, but if it didn't exist we wouldn't be here to ponder over it. [] []

[Bored chemist]

Vern,
It gets dark at night.
That may not seem a very important observation but it proves that the universe is in some way finite.
If it were not then, along any given line that you might look along at night, there would be a star.
The ideea that the universe is always here and always has been can be ruled out every time the sun sets.

[Vern]

Vern,
It gets dark at night.
That may not seem a very important observation but it proves that the universe is in some way finite.
If it were not then, along any given line that you might look along at night, there would be a star.
The ideea that the universe is always here and always has been can be ruled out every time the sun sets.

That is true only if you consider light to be ageless. The tired light scheme has light continuously converting to mass. When starlight contributes to the temperature of space debris it becomes less energetic eventually being completely consumed.

[angst]

Vern,
It gets dark at night.
That may not seem a very important observation but it proves that the universe is in some way finite.
If it were not then, along any given line that you might look along at night, there would be a star.
The ideea that the universe is always here and always has been can be ruled out every time the sun sets.

You had me thinking there....but this is not necessarily true. Light gets bent, light gets blocked out, our own atmosphere filters out great swathes of starlight. Not to mention that if mere streetlighting can so adversely affect the amount of light we perceive from beyond their range, that closer stars and galaxies might equally be seen to do likewise.

(this isn't an argument that the universe is infinite because of that, merely that the point - though initially compelling - doesn't necessarily stand up to scrutiny.  [])

[Soul Surfer]

Olbers paradox requiring the universe to be in some way limited in space or time only applies to our observable universe.  there is absolutely no reason why that represents the entire universe.

[Vern]

Olbers paradox requiring the universe to be in some way limited in space or time only applies to our observable universe.  there is absolutely no reason why that represents the entire universe.

I feel the same way. But the argument that is hard to dispose of is the red shift which, if it represents the speed of receding galaxies, would place everything in the same place some time in the past.

[lyner]

It gets dark at night.
That may not seem a very important observation but it proves that the universe is in some way finite.
If it were not then, along any given line that you might look along at night, there would be a star.

Finite or expanding or both.
Olber's Paradox is not really a paradox any more because we don't have to believe that the Universe is ageless.

You had me thinking there....but this is not necessarily true. Light gets bent, light gets blocked out, our own atmosphere filters out great swathes of starlight. Not to mention that if mere streetlighting can so adversely affect the amount of light we perceive from beyond their range, that closer stars and galaxies might equally be seen to do likewise.

This is actually a red herring because if the energy didn't reach us it would be heating up the dust etc.  in between until it was white hot and we'd still end up with an infinitely bright sky if that were all there is to it.

[angst]

You had me thinking there....but this is not necessarily true. Light gets bent, light gets blocked out, our own atmosphere filters out great swathes of starlight. Not to mention that if mere streetlighting can so adversely affect the amount of light we perceive from beyond their range, that closer stars and galaxies might equally be seen to do likewise.

This is actually a red herring because if the energy didn't reach us it would be heating up the dust etc.  in between until it was white hot and we'd still end up with an infinitely bright sky if that were all there is to it.


I'd suggest that that is a red herring, for there would be infinite space within which to dissipate that energy. You are placing the limits of the finite upon the infinite.

[Vern]

This is actually a red herring because if the energy didn't reach us it would be heating up the dust etc.  in between until it was white hot and we'd still end up with an infinitely bright sky if that were all there is to it.

Actually if you do the arithmetic it comes out to about 4 degrees K. I think it was Sir Arthur Stanley Eddington who did it.

It was some years ago that I read about this, it was before the discovery of the CMBR which was predicted back then to be in the range of 20 degrees K. Eddington postulated that starlight would warm space debris which would then radiate black body radiation at about 4 degrees K.

[LeeE]

Why is there a universe?

Because somewhere was needed in which to put everything.

If there was a big bang, what came before it, and before that, and so on?

With the "and before that, and so on" qualifier it becomes an infinitely layered question, which I'll skip as I haven't the time to fully answer it  []

Surly nothing should be, but it is, why?

If it is, then it evidentially must be, so why shouldn't it be?

[Andrew K Fletcher]

Space is not empty. Light will collide with particles smaller than atoms and as big as planets and become spent as it travels long distances, lending people to believe the universe is finite.

Vern,
It gets dark at night.
That may not seem a very important observation but it proves that the universe is in some way finite.
If it were not then, along any given line that you might look along at night, there would be a star.
The ideea that the universe is always here and always has been can be ruled out every time the sun sets.

Vern,
It gets dark at night.
That may not seem a very important observation but it proves that the universe is in some way finite.
If it were not then, along any given line that you might look along at night, there would be a star.
The ideea that the universe is always here and always has been can be ruled out every time the sun sets.

That is true only if you consider light to be ageless. The tired light scheme has light continuously converting to mass. When starlight contributes to the temperature of space debris it becomes less energetic eventually being completely consumed.

[Andrew K Fletcher]

I agree Angst

Vern,
It gets dark at night.
That may not seem a very important observation but it proves that the universe is in some way finite.
If it were not then, along any given line that you might look along at night, there would be a star.
The ideea that the universe is always here and always has been can be ruled out every time the sun sets.

You had me thinking there....but this is not necessarily true. Light gets bent, light gets blocked out, our own atmosphere filters out great swathes of starlight. Not to mention that if mere streetlighting can so adversely affect the amount of light we perceive from beyond their range, that closer stars and galaxies might equally be seen to do likewise.

(this isn't an argument that the universe is infinite because of that, merely that the point - though initially compelling - doesn't necessarily stand up to scrutiny.  [])

[Vern]

Space is not empty. Light will collide with particles smaller than atoms and as big as planets and become spent as it travels long distances, lending people to believe the universe is finite.

Hey; I like that; we've finally found something we can agree about. []

[DoctorBeaver]

Why is there a universe?

Because somewhere was needed in which to put everything.

Like an overgrown garden shed

[DoctorBeaver]

Space is not empty. Light will collide with particles smaller than atoms and as big as planets and become spent as it travels long distances, lending people to believe the universe is finite.

Surely, it collides with particles that make up the planet, not the planet itself.

[Andrew K Fletcher]

Thast's what I said didle I

Space is not empty. Light will collide with particles smaller than atoms and as big as planets and become spent as it travels long distances, lending people to believe the universe is finite.

Surely, it collides with particles that make up the planet, not the planet itself.

[lyner]

Angst / Vern
The Olber Paradox is not resolved on the grounds of dust and gas in between*. It is only resolved by, either a finite or expanding situation. That's what I meant by a red herring. As soon as you accept that light energy reaching us from distant stars is less and less OR that there are no stars beyond a certain distance, the paradox disappears.

* In an infinite Universe, each grain of dust would be receiving energy from all directions from stars and would heat up to the same temperature as the average star - thermal equilibrium would be reached. The dust would appear white hot to us.

[Vern]

I think that if light loses energy to mass as it ages the paradox will also go away. Maybe someone has detailed the math to show the paradox; I have never seen the math to see what their given values are. We might find a problem with the given values.

[lyner]

I think that if light loses energy to mass as it ages the paradox will also go away. Maybe someone has detailed the math to show the paradox; I have never seen the math to see what their given values are. We might find a problem with the given values.

I don't see that this can be correct. After a long enough period, the 'mass' to which you refer will reach a temperature at which it radiates as much power as it receives; it will reach thermal equilibrium by being at the same temperature as the sources surrounding it. Each speck of mass will glow like a star - filling in the gap / shadow which it presented when it was first introduced.