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Is our universe really expanding?


Brainstorm

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The redshift looks interesting, that's something I need to look deeper into for definite. I had a brief look on wikipedia and it appears it's a light frequency version of the Doppler effect.

One word of warning: redshift due to relative motion is not the same as redshift due to expansion of space ("cosmological redshift"). We didn't know that when Hubble first observed redshift, but we do now, at least for any model of the universe that is more or less coherent with observations.

An interesting article if you want to learn more about the more subtle aspects of this:

http://www.dark-cosmology.dk/~tamarad/papers/SciAm_BigBang.pdf

If you want something a lot less digestible:

http://www.mso.anu.edu.au/~charley/papers/DavisLineweaver04.pdf

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33 posts .. have you learned nothing here yet ? :):D

Have a good read and learn with an open mind,your just asking the same questions many people have done for centuries,

The big bang theory stands upon several pillars,its simply the best theory by far that we have,other theories are very shaky,the big bang isn't quite so,

Rather than question the validity of research that scientist's have accomplished .. read it first,its great fun when you understand ( or half understand like me :( )

JJ..:o

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33 posts .. have you learned nothing here yet ? :):D

Have a good read and learn with an open mind,your just asking the same questions many people have done for centuries,

The big bang theory stands upon several pillars,its simply the best theory by far that we have,other theories are very shaky,the big bang isn't quite so,

Rather than question the validity of research that scientist's have accomplished .. read it first,its great fun when you understand ( or half understand like me :( )

JJ..:o

I'm learning all the time, and this forum has been a wealth of knowledge already. I don't think the post count is relative though, for example, someone like Brian Cox could come on here and probably sum it all up in one post.

Please understand, I'm not putting my rationalisation across as fact, nobody has the hard and fast answers, hence 'theory'. I asked the question to hopefully gain a better knowledge of the inner workings of it all. I'm sure there are many scientists across the globe with alternative views on it too.

Of course I'm keeping an open mind too, hence my initial question, I'm open for debate on the whole thing, and yes I've learnt plenty from this thread alone. However, the BB theory still does not account for all the mass that appeared out of nowhere.

So, lets say everything is expanding, including mass, this would of course back up the Neal Adams Expanding earth theory.

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But we are regularly (and more closely!) "visited" by other stars. Indeed, "waiting a bit" might save considerably on the fuel bills for inter-stellar travel... :o

What are these visits of which you speak, I'm interested to know.

Scientists think there is no "center of the universe".

To be honest, in my humble and uneducated opinion, if there was a point of explosion/expansion to fit the big bang model... there must have been a 'start point.' Whether that is in the centre or not is another questions, as this would depend upon the rate of expansion being even in all directions from the point of origin.

I think somewhere I heard/read/watched someone that stated a hypothesis surrounding the what makes up the fabric of our space-time universe, which is created from the presence of mass... the more 'mass' or matter you have, the more universe there is.

So for every kilo of mass there is what... a square AU of space? I don't know what the ratio would be, we don't know the extents of the universe as we can't see more than 13.7billions years into the past and the universe expanded at a rate faster than light can travel.

But it is clear from plenty (and I mean PLENTY) of scientific effort that everything (for the most part forgetting local gravitationally influenced impacts/trajectories) in the universe is still moving away from everything else (thus expanding.)

Hearing Brian Cox's Wonders of the Universe episode 1 regarding Entropy heralding the death of the universe has been thought provoking as to how the universe began... how did it have so much energy at one point, is it that our universe was fed from a collapsing/evaporating black hole from a higher state universe.

Maybe a black hole has so much mass that the energy cannot be physically contained within it's host reality and is thus forced to punch an inter-dimensional/inter-reality/inter-universe hole through what I have no other term for other than sub-space, the contents of which spill into the new / existing reality as mainly pure energy (due to the high gravitational affects of the black hole,) which starts to very quickly form into matter or varying sorts and causing that reality to expand in the same way ours did.

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So, lets say everything is expanding, including mass,

Objects that are bound by other than gravitational forces do not expand; they are merely a very tiny fraction larger because the equilibrium between the attractional forces that bind them and the tug of expanding space is slightly different, but at small scales the difference is negligible (in theories that include a final big rip when expansion really runs away, right up to an instant before the end of the universe when all particles finally disconnect from all the others).

The Hubble constant is roughly 72 km/s per Megaparsec, but a Megaparsec is roughly 20000000000000000000 larger than a kilometre, so don't expect that space to expand that fast at smaller scale (at least not for now).

And as long as expansion is constant you can't really notice the effect directly, as the equilibrium between the forces and the tug of expanding space remains the same unless you notice changes in the rate of expansion, and those are even slower.

It's all explained in that first article I linked, but of course you'd only know that if you'd read it :o.

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[quote name=Brainstorm;1736840

If there was nothing there before it' date=' what caused it, and where did all the matter come from?

The sentence above doesn't make sense, quite literally.

The BB is a theory in which the dimension which we call time, and which most probably we do not understand, 'emerged' or 'was created' at the moment of the big bang. In this theory, therefore, there can be no 'before.' So the phrase 'before the big bang' is entirely without meaning. If there was a 'before' there wasn't a big bang. If there was a big bang, there wasn't a 'before.' You cannot have both in the same sentence and make sense, just as you can't say, for example, 'What shade of blue is that red car?' If it is a red car it isn't blue.

This does not mean you have to accept the BB, but you do need to say, 'I cannot accept the idea that time can have a beginning.'

Nor, if you do believe in the BB, do you have to believe in creation from nothing. I doubt that many BB theorists believe any such thing. You can see the BB as lying embedded in something wider, some greater reality constructed of dimensions unknown to us. So I'm happy to speculate (but not theorise) that there might be something outside the BB but not 'before' it because 'before' desribes the relationship of one moment to another on the continuum we call time.

One more thing; you make it clear that you are sceptical about theories in science. Quite right too. Feynman said science is a culture of doubt. But I thnk you may have forgotten to doubt one of your own theories here. The idea that there is a past, a present and a future is a theory of time. Follow your own advice and doubt it. I certainly do.

Olly

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To be honest, in my humble and uneducated opinion, if there was a point of explosion/expansion to fit the big bang model... there must have been a 'start point.'

The point made in countless threads is that the big bang isn't objects moving from a starting point into space that was formerly empty. It's objects staying put but the space itself between the objects expanding.

It doesn't even depend in se on the universe as a whole being finite and point sized at the big bang with space itself curled up on itself, it's just that whatever is in the portion of the universe we can see now (and if inflation theory is right that's a very small part indeed) was then packed in a very, very small space.

I guess it would've been better to call it the big inflating, but that doesn't really have the same ring to it (not to mention that nowadays inflation is used to denote a much more aggressive variant of space expansion in a theory that has hijacked that word).

The big stretch?

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To be honest, in my humble and uneducated opinion, if there was a point of explosion/expansion to fit the big bang model... there must have been a 'start point.' Whether that is in the centre or not is another questions, as this would depend upon the rate of expansion being even in all directions from the point of origin.

Forget explosions and expansions, they are the wrong mental model for most people, precisely because they automatically bring in the idea of a centre of explosion/expansion. Maybe we should call it "The Big Stretch".

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What are these visits of which you speak, I'm interested to know.

To be honest, in my humble and uneducated opinion, if there was a point of explosion/expansion to fit the big bang model... there must have been a 'start point.' Whether that is in the centre or not is another questions, as this would depend upon the rate of expansion being even in all directions from the point of origin.

I think somewhere I heard/read/watched someone that stated a hypothesis surrounding the what makes up the fabric of our space-time universe, which is created from the presence of mass... the more 'mass' or matter you have, the more universe there is.

So for every kilo of mass there is what... a square AU of space? I don't know what the ratio would be, we don't know the extents of the universe as we can't see more than 13.7billions years into the past and the universe expanded at a rate faster than light can travel.

But it is clear from plenty (and I mean PLENTY) of scientific effort that everything (for the most part forgetting local gravitationally influenced impacts/trajectories) in the universe is still moving away from everything else (thus expanding.)

Hearing Brian Cox's Wonders of the Universe episode 1 regarding Entropy heralding the death of the universe has been thought provoking as to how the universe began... how did it have so much energy at one point, is it that our universe was fed from a collapsing/evaporating black hole from a higher state universe.

Maybe a black hole has so much mass that the energy cannot be physically contained within it's host reality and is thus forced to punch an inter-dimensional/inter-reality/inter-universe hole through what I have no other term for other than sub-space, the contents of which spill into the new / existing reality as mainly pure energy (due to the high gravitational affects of the black hole,) which starts to very quickly form into matter or varying sorts and causing that reality to expand in the same way ours did.

I love the idea, it's one that has crossed my mind also but with regard to the universe having a centre...

Well we think it doesn't as it was an explosion of space (doesn't have a central point) not an explosion in space where everything radiates from a central position. Everything was present and expands equally everywhere not just from the centre. I can't get my head round it my self but This helps http://www.phys.ncku.edu.tw/mirrors/physicsfaq/Relativity/GR/centre.html

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Forget explosions and expansions, they are the wrong mental model for most people, precisely because they automatically bring in the idea of a centre of explosion/expansion. Maybe we should call it "The Big Stretch".

The big stretch... I like it

Like my balloon lol

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I love the idea, it's one that has crossed my mind also but with regard to the universe having a centre...

Well we think it doesn't as it was an explosion of space (doesn't have a central point) not an explosion in space where everything radiates from a central position. Everything was present and expands equally everywhere not just from the centre. I can't get my head round it my self but This helps Where is the centre of the universe?

There are flaws with the idea... as I understand it currently, is that each subsequently created reality would have less than the (and I leave 'less' as an ambiguous reference on purpose) reality it was spilt from. Which would suggest a decreasing 'super-universe.' Mathematically I don't know where that stands. Hawkins has theorised that Black Holes simply 'evaporate.' Others made it a quest to conserve 'information' and suggest that it cannot 'evaporate' and therefore the 'information' cannot be lost.

If Hawkins believes the Black Hole will disappear somehow due to some mathematics or principles of physics (which I do not have the knowledge of unfortunately,) then my suggestion regarding a Black Hole spilling into alternate realities might seem somehow plausible.

Hopefully, I will get to study this in the next year or so and build on this a little (or blow it out of the water as complete codswallop, either way :o.)

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Another way I've been thinking about this lately is that, if you imagine the black hole as something similar to those little plasticy rubber poppers that I used to play with when I was at school... it was like a semi-spheroid that when you turned it inside out, it would fight to regain it's shape and then 'pop' propelling itself into the air.

I'm thinking that the black hole amasses so much matter that possibly it's surface tension becomes too much for the laws of physics and thus, it breaks (out of) this reality. Propelling the matter/energy into the next at such a terrific rate you get a big bang type scenario.

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I'm not sure I can get my head around the whole "big bang" thing. Which doesn't mean I don't believe it could have happened. I just don't have the necessary hooks to hang the idea on at the moment. Perhaps a little like people who observed the world as "flat" couldn't get their head around the idea of the world being round. I mean, people would fall off the bottom, right? That's obvious to anyone! I can't yet create a mental model of how it's possible for time and matter not to have existed. Perhaps even "nothing" didn't exist. The universe just wasn't.

James

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There are flaws with the idea... as I understand it currently, is that each subsequently created reality would have less than the (and I leave 'less' as an ambiguous reference on purpose) reality it was spilt from. Which would suggest a decreasing 'super-universe.' Mathematically I don't know where that stands. Hawkins has theorised that Black Holes simply 'evaporate.' Others made it a quest to conserve 'information' and suggest that it cannot 'evaporate' and therefore the 'information' cannot be lost.

If Hawkins believes the Black Hole will disappear somehow due to some mathematics or principles of physics (which I do not have the knowledge of unfortunately,) then my suggestion regarding a Black Hole spilling into alternate realities might seem somehow plausible.

Hopefully, I will get to study this in the next year or so and build on this a little (or blow it out of the water as complete codswallop, either way :o.)

Me too, my knowledge of maths, science and physics are way below what's required but I've learnt more in the last 6 months than I have in 30 years lol. Didn't hawking admit his theory was wrong though? According to one documentary he did but upon doing so he claimed that that other theory is also wrong???

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If Hawkins believes the Black Hole will disappear somehow due to some mathematics or principles of physics (which I do not have the knowledge of unfortunately,) then my suggestion regarding a Black Hole spilling into alternate realities might seem somehow plausible.

It's (fittingly) called Hawking radiation. It's actually quite simple. We know that matter inside the event horizon of a black hole can't escape because its escape velocity would have to be greater than the speed of light.

However, quantum physics says that there is an uncertainty in the location of a particle and they can "jump" around a bit.

So a particle that is very close, but inside the event horizon can, by quantum physical effects, suddenly find itself just outside the event horizon and is then able to escape; or radiate away.

If lots of particles do that over time, the mass of the black hole reduces and therefore the event horizon shrinks. That brings more particles closer to the event horizon that can then also radiate away. And so on...

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It's (fittingly) called Hawking radiation. It's actually quite simple. We know that matter inside the event horizon of a black hole can't escape because its escape velocity would have to be greater than the speed of light.

However, quantum physics says that there is an uncertainty in the location of a particle and they can "jump" around a bit.

So a particle that is very close, but inside the event horizon can, by quantum physical effects, suddenly find itself just outside the event horizon and is then able to escape; or radiate away.

If lots of particles do that over time, the mass of the black hole reduces and therefore the event horizon shrinks. That brings more particles closer to the event horizon that can then also radiate away. And so on...

I've seen an experiment where they fire particles of light at a solid object with 2 identical 'slits' in it allowing the light to travel through the slits. At the other side there was a detector showing where the light particles had hit. Interestingly instead of the light particles creating 2 patterns of light as you would expect (light travels in straight lines)... It created3!!! Either the photons split or they were in two places at the same time!!!

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I've seen an experiment where they fire particles of light at a solid object with 2 identical 'slits' in it allowing the light to travel through the slits. At the other side there was a detector showing where the light particles had hit. Interestingly instead of the light particles creating 2 patterns of light as you would expect (light travels in straight lines)... It created3!!! Either the photons split or they were in two places at the same time!!!

This is usually called 'Youngs slits', and demonstrates how interference works. It's pretty simple to derive mathematically if you take a wave model of light, and pretty obvious what's happening physically if you have lots of photons in the experiment.

The really weird thing, which I think you're eluding to above, is that it still works even if you only fire one photon through the experiment every second/day/year. Somehow the photons 'know' how to interfer even though they are on their own. Wierd quantum mechanics in action :o

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Just had a thought. If Einstein is right and energy is mass and vice verse. Could black holes simply be turning mass back into energy and erupting it back into the universe via gamma rays?

Maybe that energy then converts into dark matter? ;-)

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This is usually called 'Youngs slits', and demonstrates how interference works. It's pretty simple to derive mathematically if you take a wave model of light, and pretty obvious what's happening physically if you have lots of photons in the experiment.

The really weird thing, which I think you're eluding to above, is that it still works even if you only fire one photon through the experiment every second/day/year. Somehow the photons 'know' how to interfer even though they are on their own. Wierd quantum mechanics in action :o

Maybe for every Photon there is some anti/dark version that we've not thus far been able to detect. So if such a photon existed, it may be possible for it to take a different path to the visible Photon, if that is the case, then maybe it could help to cause the interference 'wave' pattern.

Although, having said that, I was reading something in New Scientist where they performed a kind of long distance slit test at the Canary Islands, which would probably make my speculation bunkem.

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Maybe that energy then converts into dark matter? ;-)

I remember reading something somewhere that stated some scientist got hydrogen gas to near absolute zero and the gas started to behave very differently and started to form into one solid mass (wording may not be wholly correct there!)

If that was correct, perhaps Dark Matter is merely normal matter with no latent energy in it whatsoever, and maybe because of this... we can't see it?

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