The Great Universe Debate

[Countryfox]

6 hours ago, leicsmac said:

Aha! My kind of topic.

 

Right...

 

The Universe is finite - that much we know, both in terms of what we can observe (up to around 46 billion lightyears away) and in terms of what we can't (everything beyond that up to a limit of anywhere between 150-550 billion lightyears). That being said, there are some schools of thought that suggest it is infinite - but the theory that it is finite tends to hold a lot more water these days. 

 

There likely won't be an event within this Universe that will cause it to spontaneously collapse - the energy that we can't observe yet (but we know has to be there) that drives gravitational expansion is much too strong for that. The most likely outcome is simply continual expansion and eventual heat death.

 

It is perfectly possible, however, that when the Big Bang expansion event happened (I really dislike that term) that other universes were "created" (again I use that term loosely) by the chance event that caused the initial expansion of ours. That's what the multiverse theory is based on, really.

 

Regarding "before" the Big Bang event - it's really something of an moot point, as time is just something used to measure another dimension within this universe...and before that event there were no dimensions. 

 

 

You should give it a go - it's actually a pretty decent read.

 

That being said, there aren't that many books out there that explain these matters in a good way - A Short History of Nearly Everything by Bill Bryson does well, but the nature of the Universe isn't the only thing that book covers.

 

 

Yep. You've just pretty much nailed down the basis of the multi-universe theory - that there are so many chances to "make" a Universe, that it is indeed happening all the time because the right chance conditions for it are happening more often (if there is such a thing) that folks might think. Of course, we cannot observe to prove this at all.

 

Again though, outside our universe to think of "space" is moot because that is merely a term used to describe dimensions within our own universe...it's a decent way to explain it, though.

 

 

I've been hooked since I was very little. Did two degrees on it, still love it now.

 

Some people find the idea of all that space out there intimidating. I find it comforting.

 

 

The odds as stipulated in the Drake Equation (and how it has been modified over the years since it was thought of ) would bear this out. 100 billion planets in our galaxy alone (and that's a lowball estimate, given that Kepler seems to suggest now that 60-95% of all stars in our galaxy have planetary systems with them), and at least 200 billion galaxies in the observable Universe alone...that's an awful lot of planets out there.

 

However, where the Drake Equation falls down is having only one frame of reference for conditions necessary to support life - Earth. We simply aren't sure of what exactly it took to generate life here...so we can't be sure of what it would take elsewhere, either. Should we find simple life on either Europa or Enceladus in the future (and I sincerely hope that we do) that would greatly boost the odds of at least simple life existing elsewhere. One more reason to get out there!

 

 

Yeah, it's such a shame that we seem to be so caught up in our petty differences here on Earth that we don't seem to focus adequately on getting out into space. With the right will it could be done, and quite frankly sooner or later it's going to need to be done, because Earth isn't going to remain this habitable forever, either through human action or through simple natural changes (bear in mind that all of recorded human history has happened during a temperate flyspeck of time in geological terms).

 

And yes, how gravity affects time is something of a mindscrew - and Interstellar did better than most Hollywood movies in depicting it correctly. Still one of my favourite movies. It's definitely something to consider should humans ever venture out into areas where relativistic effects come into play - either going near them or making a ship that goes so fast that comes into account.

 

 

Yup - any one of these reasons might be right, or a combination of them all, or none of them.

 

The only way we're going to know for sure is to get out there, to find out as much as we can, and see what we find.

 

Also, I really enjoy talking about this and its sort of my area of expertise, so if folks have any questions at all on the topic please ask if you wish.

You're talking absolute sh1te ...    The universe is in a pendant thingy hanging on a collar round a cats neck ...    I've seen it on the telly so it must be right.    There ...   That's put that one to bed.

[TiffToff88]

31 minutes ago, Countryfox said:

You're talking absolute sh1te ...    The universe is in a pendant thingy hanging on a collar round a cats neck ...    I've seen it on the telly so it must be right.    There ...   That's put that one to bed.

The galaxy is on Orion's belt?

[Jattdogg]

...Time for some marijuana....

[Countryfox]

6 minutes ago, TiffToff88 said:

The galaxy is on Orion's belt?

 Galaxy, Fruit and nut, Kit Kat, the universe ...    They're all the same ...

[Buce]

3 minutes ago, Jattdogg said:

...Time for some marijuana....

 

It's always time for some marijuana...

 

 

 

[Stadt]

When I occasionally think about space I get so far and just nah fcuk this, my tiny mortal brain can't comprehend this so then I think about football, or tits, for instance.

Edited 18 October 2017 by Wookie

[Rain King]

45 minutes ago, Wookie said:

When I occasionally think about space I get so far and just nah fcuk this, my tiny mortal brain can't comprehend this so then I think about football, or tits, for instance.

Ridiculous as it sounds I used to think about it a lot as a 7 or 8 year old. Was always asking my dad what was before the big bang. I couldn't (still can't) comprehend that there was nothing and then suddenly there was something. It used to really mess with my tiny mind and several times I cried myself to sleep at the thought of it all.

 

Now like you I just think of something else to take my mind off it as it really does my head in.

Edited 18 October 2017 by pds

[nnfox]

Loving this thread.  This is really interesting stuff, thankyou @TiffToff88 for starting it and in particular @leicsmac for your insightful input.

 

I'm definitely in the multi-verse camp, if it can happen once, it will happen again.

 

Travelling through space at the speed of light whilst slowing time sounds like a lot of fun, but I'm not 100% certain of all the technicalities.

 

 

[Benguin]

We can observe the universe expanding so we know it had a beginning which means that either the kalam cosmological argument for the existence of god is true or universes begin then end then begin again and so on or finally nothing proceeded the big bang. Obviously there are other options but those three are the only credible theories without wild speculation.

 

The multi verse is nonsense 

[Izzy]

I genuinely didn't realise this forum had so many smart and intelligent posters having read this thread.

 

Looking at most of the guff on the football forum, I figured we all were mainly idiots.

Edited 18 October 2017 by Izzy Muzzett

[Kopfkino]

3 hours ago, leicsmac said:

There is an awful lot to find out about our own planet - especially the oceans - but these things can certainly be done concurrently.

 

If the "space" (loose term) where such events occur is indeed infinite, then yes - there are a very large number of possible universes that will have spawned within that space...but that's a big if and something that likely can't be quantified anyway.

 

No of course, I accept that and it can teach us a lot about our own world, just for me I'm more interested in what is here and what goes on here. 

 

Of course it can't be quantified and we will probably never know, but this is why I like the intersection with philosophy. It's fascinating, but gauling and to think we could possibly just relive life over and over again as a result and never know. The notion of Solipsism (not that I believe it), and therefore its opposition to science, is another thing I find bizarre and fascinating. Maybe its the equivocality of philosophy which draws me in compared to the relative brutality of science but with the universe you can combine the two more.

[Stadt]

 

[Carl the Llama]

I'm pretty convinced that the vacuum we call space either must be infinite or if that's not the case and it has defined boundaries then it must be a small piece of something which is infinite.  If it has a shape then that implies outside forces acting on it reinforcing the boundary.  My analogy would be how a bubble of air rising from a vent in the ocean has its shape only because of the forces exerted upon it by the surrounding liquid.  Above the water where those forces disband it ceases to be a bubble and becomes part of what to the bubble must seem to be an infinite sea of air surrounding our planet.  But that vast sea of air is itself an air bubble within the vast vacuum of space, held around our planet by its gravitational pull.  I believe that either that vacuum carries on infinitely in all directions engulfing billions of pockets of gas and rock and metal or else it is itself a bubble of nothing surrounded by something which itself is either infinite or else an even larger bubble of something within an even larger bubble of nothing/something else within an even larger bubble of nothing/something else within an even larger etc.

 

I am however open to the idea that within the possibly infinite nothing there is a finite amount of mass and if that's the case then I guess the universe can be defined as the area within the nothing where there is something.

Edited 18 October 2017 by Carl the Llama

[leicsmac]

2 hours ago, nnfox said:

Loving this thread.  This is really interesting stuff, thankyou @TiffToff88 for starting it and in particular @leicsmac for your insightful input.

 

I'm definitely in the multi-verse camp, if it can happen once, it will happen again.

 

Travelling through space at the speed of light whilst slowing time sounds like a lot of fun, but I'm not 100% certain of all the technicalities.

 

 

No problem!

 

The multiverse theory is interesting, but it needs much more solid evidence - time dilation, on the other hand, is very quantifiable.

 

2 hours ago, Benguin said:

We can observe the universe expanding so we know it had a beginning which means that either the kalam cosmological argument for the existence of god is true or universes begin then end then begin again and so on or finally nothing proceeded the big bang. Obviously there are other options but those three are the only credible theories without wild speculation.

 

The multi verse is nonsense 

I wouldn't discount the idea of a multiverse out of hand - with what we know of quantum mechanics it might make sense. With respect to the beginning of the Universe...the third of your theories is most likely the correct one...but who knows?

 

 

2 hours ago, KingGTF said:

 

No of course, I accept that and it can teach us a lot about our own world, just for me I'm more interested in what is here and what goes on here. 

 

Of course it can't be quantified and we will probably never know, but this is why I like the intersection with philosophy. It's fascinating, but gauling and to think we could possibly just relive life over and over again as a result and never know. The notion of Solipsism (not that I believe it), and therefore its opposition to science, is another thing I find bizarre and fascinating. Maybe its the equivocality of philosophy which draws me in compared to the relative brutality of science but with the universe you can combine the two more.

That's totally fair enough - for me it's a matter of necessity more than anything else.

 

And yeah, some parts of the Universe that aren't quantifiable (and possibly never will be purely due to human limitation) you do veer into philosophy as opposed to hard science. I don't hold much truck with Solipsism either, likely for the same reasons you do...but when it comes to the cosmological there is an undeniable overlap given the sheer amount we can't yet confirm.

 

 

[Benguin]

42 minutes ago, leicsmac said:

No problem!

 

The multiverse theory is interesting, but it needs much more solid evidence - time dilation, on the other hand, is very quantifiable.

 

I wouldn't discount the idea of a multiverse out of hand - with what we know of quantum mechanics it might make sense. With respect to the beginning of the Universe...the third of your theories is most likely the correct one...but who knows?

 

 

That's totally fair enough - for me it's a matter of necessity more than anything else.

 

And yeah, some parts of the Universe that aren't quantifiable (and possibly never will be purely due to human limitation) you do veer into philosophy as opposed to hard science. I don't hold much truck with Solipsism either, likely for the same reasons you do...but when it comes to the cosmological there is an undeniable overlap given the sheer amount we can't yet confirm.

 

 

The reason I discount the multi-verse is because there is no evidence at all other than a fine tuned universe like ours is too improbable without it and God seems too much of an implausible solution. 

[leicsmac]

49 minutes ago, Benguin said:

The reason I discount the multi-verse is because there is no evidence at all other than a fine tuned universe like ours is too improbable without it and God seems too much of an implausible solution. 

I think the first part of what you state there is reason enough to at least entertain the possibility tbh. The idea of our universe being one where the fundamental constants are arranged just so...that implies luck and countless others "tried" where it wasn't the case.

 

Of course though, actual tangible evidence is very thin on the ground.

[Sampson]

Just wanted to add that PBS Space Time is an incredible YouTube channel for physics stuff like this. Must have watched all their videos. Mindblowing stuff.

 

Also physics definitely interacts with philosophy as per the debate above. After watching all those videos I do find human free-will a bit of a stretch these days for example. It appears to me either a deterministic or random model of the universe is the only one that makes sense and it seems unlikely humans have any free-will or any influence on how the particles which make up our brains function for example.

Edited 19 October 2017 by Sampson

[Benguin]

2 hours ago, leicsmac said:

I think the first part of what you state there is reason enough to at least entertain the possibility tbh. The idea of our universe being one where the fundamental constants are arranged just so...that implies luck and countless others "tried" where it wasn't the case.

 

Of course though, actual tangible evidence is very thin on the ground.

Is it though? To me multiverse is an all or nothing theory in that if it is correct there would have to be infinite possibilities not too dissimilar to a rick and Morty style universe. To me multiverse is in the same category as god. Exciting prospect but one not worth any real speculation besides "I wonder if I'm sleeping with Emma Watson in a parallel universe."

[Sampson]

19 minutes ago, Benguin said:

Is it though? To me multiverse is an all or nothing theory in that if it is correct there would have to be infinite possibilities not too dissimilar to a rick and Morty style universe. To me multiverse is in the same category as god. Exciting prospect but one not worth any real speculation besides "I wonder if I'm sleeping with Emma Watson in a parallel universe."

There wouldn't have to be infinite possibilities necessarily, only different formations of the laws of physics.

 

I think you're confusing multiverse theory with the many-world interpretation of quantum mechanics which is what Rik and Morty do.

Edited 19 October 2017 by Sampson

[Benguin]

8 minutes ago, Sampson said:

There wouldn't have to be infinite possibilities necessarily, only different formations of the laws of physics.

 

I think you're confusing multiverse theory with the many-world interpreation of quantum mechanics which is what Rik and Morty do.

A finite amount of universes creates more problems to the theory rather than solving them. 

 

I am quite sure I'm not confusing the theory.

Edited 19 October 2017 by Benguin

[Benguin]

To clarify my original point I am saying the multi verse theory would have to be the many world interpretation and that's just silly.

[Sampson]

52 minutes ago, Benguin said:

A finite amount of universes creates more problems to the theory rather than solving them. 

 

I am quite sure I'm not the theory.

But even so infinite potential different laws of physics at the point of creation does not neceserially mean infinite timelines where everything that could happen does happen.

 

48 minutes ago, Benguin said:

To clarify my original point I am saying the multi verse theory would have to be the many world interpretation and that's just silly.

But many worlds theory is not multiple universes at the point of creation, it's the idea that any time a particle's wave function collapses and it can be in one of numerous positions, it is simultaneously in all those positions and the universe "splits" into parallel universes each one containing each possible position of the particle and therefore every time we make a decision we simultanously make every possible decision but the universe "splits" and we only observe one path of all this, so there are parallel universes of every possible decision and collection of particles ever possible.

 

It makes the most sense from Occam's Razors point if view in that it requires the least jumps of faith as an explanation of Quantum Mechanics. I'm not sure I'm fully behind it as I think the Copenhagen Interpretation is better but the Many-Worlds Interpretation isn't just something some guy made up on the fly, - particles do exist simultanously in all possible locations they can be at the same time until they are measured and we can measure the probability of where that might be to minute detail (and Quantum Mechanics is the most rigerously tested and most mathematically sound Theory of the Universe humans have ever come up with) and given a particle which was previously in numerous locations simultaneously now only appears in one - what happened to other locations it was in? Given the maths is objective on this and a much better indicator of the universe than our human senses and that the maths only predicts that the probability of where that particle could be but doesn't say that what we perceive is the "correct" answer - it's not far-fetched and requires less leaps of faith and less additional parts to the theory on top of the maths to theorise that it continued to be in every possible position it could possibly be simultanously but the universe "split" and we could only observe this version -than it is to say the particle was in every possible position it could be simultanously and then decided to be in one of those position through random chance or by design with no explanation of what decides that or why it would be in every possible location beforehand or how it managed to appear that way if so and that explanation takes much more explaining away and leaps of faith than many worlds theory does.

 

I'm not saying it's right, but it absolutely isn't silly or some explanation some guy just thought up off the top of their heads and it's mainstream physics for a reason. It's a genuinely sound theory and one which requires the fewest leaps of faith for one of the most bizarre and mind-bending pieces of natural phenomena in the universe.

Edited 19 October 2017 by Sampson

[Finnegan]

Surely it's impossible for the universe to be both expanding and infinite. 

 

So the fact it's expanding means it isn't infinite. 

 

I can accept the theory that there are infinite universes, that's slightly different. 

[Crinklyfox]

If we live in an infinite universe and my memory of basic maths is OK then it appears that the possibility of a single event occurring is zero, as any number divided by infinity is zero.

 

So if that holds nothing should ever occur - but it does.

 

 

[Buce]

 

If you have 10 mins or so to spare, this short story by Asimov is a brilliant read and highly pertinent to this topic.