Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Johann Mahne on 30/07/2011 16:40:03
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Astronomers explain that galaxies are receeding away from us faster than they should be.
They also state that the following:
a)Gravity should be slowing down the expansion of the universe started by the big bang,but instead the expansion is accelerating.
b)Galaxies that are very far away are receeding at speeds that exeed the speed of light,and can never be observed.This we are told, is caused by the expansion of space time itself.
My question is:
If these facts are true,then very remote galaxies are emitting light that can never reach us.
But since gravity also travels at the speed of light, then the gravity of these galaxies cannot connect to our local group of galaxies.The same effect applies to all galaxy groups.
As time moves on, more galaxies will enter zones of expansion relative to us where they are receeding at the speed of light, and will also lose their gravity connection to our local group of galaxies.Again the same effect applies to all galaxies.
So does this not mean that the total mass of the universe cannot effectively act on the universe itself,and that this is the cause of the accelerating expansion and not Dark Energy?
Thanks for reading this rather long and convoluted question.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi51.tinypic.com%2Ff3gtjo.png&hash=ba24589b2654cf961e19b9ceb8eac05d)
3D Image of Space time expansion from wikipedia,showing that all remote galaxies can be observed
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi53.tinypic.com%2F27yml9c.png&hash=36f2e385350e0df85dbd894f3136ad90)
Plan view of Space Time expansion,showing the same as above
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi51.tinypic.com%2F2nipukx.png&hash=bb703291025635809d6d2272213c0484)
Plan view of Space Time expansion showing very rapid expansion from the start
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2F&hash=3cd4f4119996b42d10f5ed9eb0e8d712)
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Yes, dark energy explains it, but does not proove it is the actual theory. Dark energy is like a plaster, healing the wounds of our universal explanation, equally, a paradox similar to explaining fundamental matter in the form of dark matter. It may turn out however, as it often does in quantum physics, that dark energy is just some mathematical complex of information that modern quantum mechanics has not taken into consideration yet.
There has been an interesting link recently however, between zero point energy and the dark energy phenom, which interesting since we have had a thread discussing this recently here at TNS.
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So does this not mean that the total mass of the universe cannot effectively act on the universe itself,
Interesting thought.
The way I see it is each small volume of the universe is connected to adjoining volumes and so they are all interconnected, even if expanding faster than light.
Think of a piece of elastic stretching faster than light we would not be able to see the end but it is still one piece of elastic and all parts of it feel the pull from adjacent parts.
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Depend on how you look at it Johan. When that 'space' expands, do you think it can do so without gravity being there? Under that assumption we have a 'space' with gravity, and the 'expansion' without a 'gravity'. But as the distance the expansion grows with, from us seen, are slower than light, the gravity locally always will have time to fill it in.
You are correct in that it makes for a very weird 'space' if there was no 'gravity' existent. The other way, that I think is true personally, is that you can't have what we call 'space' without its 'metric' which to me is gravity. So then the expansion brings with it 'gravity' and there will be no 'faults' of 'space'.
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Thanks again to everyone for taking the time to read through my long question.
When that 'space' expands, do you think it can do so without gravity being there?
Yor_on,
I'm not saying that there is no gravity acting on remote regions of space,but that gravity is reducing over time for the whole universe due to the rapid expansion of space,and so space time expands even faster.More along the lines as MikeS has summarised.I'm not saying that the universe is losing mass either.
So if the expansion of space time was very rapid to start off with, we would not be able to see all the quasars and we would think that we knew the mass of the universe, but in fact we could not observe the whole universe.
This would also mean that gravity could not reach everywhere either.
So my question is could this replace "Dark Energy" ?
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No, there are two reasons why it couldn't replace dark energy.
First, the models out there for the behavior of the universe already take into account that distant matter can't pull on us.
Second, if there were somehow more matter than we knew about it would slow down the expansion of the universe. But dark energy was introduced because the universe is expanding faster than we can explain, so dark energy must be something very different from extra matter.
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BLACK HOLES, EXPANSION, AND DARK ENERGY
In the continuum of space and time, exists the dichotomy of matter and energy. All things exist as both matter and energy, but are experienced as one or the other.
As energy, all things exist as wave patterns. Most wave patterns are interferences of simpler wave patterns. The simplest wave forms are those that do not interfere with other waves. These simplest wave forms hold their shape as they propagate. There are three such wave forms.
The first such wave form is seen in three dimensions as the spherical expansion wave of a bomb blast, and in two dimensions as the circular wave of expansion on the water where a rock was tossed in. The second wave form is seen in three dimensions as the cone of sonic boom following an aircraft traveling faster than sound, and in two dimensions as the V-wake on the water where the boat is traveling faster than the water wave. The third wave form is seen in three dimensions as the propagation torus of a smoke ring and is seen in two dimensions as the double vortexes of an oar stroke on the water.
The Torus is a particle of discrete exchange, from one point to another. The object exchanges position and momentum. While the spherical wave shows position, and the conic wave shows momentum, the torus shows both at the same time, and has a dynamic finite unbounded reality. The volumes of the cone, sphere, and torus are mathematically related as static objects.
The Universe is a local density fluctuation. (a wave pulse) On this local density fluctuation wave, lesser wave forms may exist. All simple wave forms are also local density fluctuations, and as such are indeed universes in their own right, where other waves may exist.
Consider the torus as a universe. Einstein said that gravity is indistinguishable from acceleration. There is both linear acceleration and angular acceleration. Although the torus as a whole travels in a straight line, every local point on the torus travels in a circle and experiences angular acceleration.
The rubber sheet model of gravity and curved space translates directly to the propagating torus with angular acceleration. Acceleration is downward on the rubber sheet and outward on the torus. The tension field that separates the inside of the torus from the outside holds its shape as a simple two dimensional field of space and time just as the rubber sheet does.
Experimentally verifiable is that a big fat slow smoke ring generated in a room with very still air will eventually possess a bulge that travels in a circle on the surface of the smoke ring. This bulge, being a gravitational depression, gathers more of the energy of the field toward itself. Finally the bulge gathers enough material to collapse the field and eject a new, smaller smoke ring out in the same direction as the first torus. This collapse is a black hole to the first torus, and a white hole to the second torus, where the axes of space and time in that second torus have reversed.
While gravity tends to draw depressions together locally on a dynamic torus, even to the point of field collapse, other areas on a torus expand and contract globally as the torus propagates along without regard to local phenomenon on the surface. This is quintessence. The inertia of the torus to propagate is its dark energy. This is a two-dimensional example of the process that we experience in three dimensions.
From website removed by Dan Echegoyen tel number
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Dan Echegoyen
website and tel number removed
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Dan,
We do not like simple reposts of material from other fora and websites. Additionally, we are not a forum for advertising your website. I have shrunk/edited the above message for these reasons.
Those things aside please do enter the discussion here or feel free explain your points of view(which it appears you have spent a lot of time developing) on the new theories board - but please no cut'n'paste job .
Cheers -
imatfaal
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Johann, either we assume that gravity is everywhere there is a noticeable 'space' for us, and then gravity as such is what defines that 'space', or we don't.
What you seem to assume is that 'mass is gravity', and with the 'space' expanding 'gravity' becomes diluted as there will be less mass over a whole SpaceTime. But 'mass' is energy, and 'Space' seems to be 'energy' too, even though not measurable macroscopically. We live in a place defined by mass and time to have a 'groundstate' macroscopically in where we find 'space' to be a nothing, but Einstein showed us that this 'nothing' can be 'shaped' by what we call 'gravity'. So even though no aether it is still adaptable and so 'something'. Think of that as we do lights 'duality', something, that to us is a nothing :)
So if we assume a SpaceTime equilibrium to be a principle for this universe to be in balance and exist, then we have to assume that with the expansion that equilibrium will be uphold too. That should mean that, with the 'distances' growing, there also should be enough 'energy' pasted in to keep that balance.
As for gravity not reaching everywhere?
Either it is the metric of space, then it is everywhere. Or it is not. Furthermore, we have no proofs of us ever being able to see, and measure, a whole SpaceTime at any time, we can only build on what we see today.
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Yor_On, i agree that gravity affects and shapes space and that all space must have gravity.
But if astronomers say that:
a) gravity travels at the speed of light
b) The metric expansion of space exeeds the speed of light
Then i don't see how gravity can reach and couple everywhere across the universe?
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Johann - there are regions of the universe that we can never communicate and can never communicate with us. Both gravity and light are limited in speed - and thus areas of the universe are cut off from us for ever. The universe is not gravitationally bound - even the observable universe is not bound and is in fact heading for a cold boring heat death where everything has separated from everything else
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Discussion on validity of claim that universe is expanding has been split off and moved to new theories. Please do not derail discussions like this - open a new topic. Thanks - imatfaal