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Stargazers spot dark energy
"The distribution of galaxies and the time it takes for
galactic clusters to form are behind a University of Queensland claim confirming the existence of dark energy. Dark energy has been predicted as a defender of Einsteinian models of the universe, ever since the 1990s when astrophysicists identified the accelerating expansion of the universe." See: http://www.theregister.co.uk/2011/05...t_dark_energy/ |
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Stargazers spot dark energy
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Stargazers spot dark energy
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Stargazers spot dark energy
David Spain wrote:
Only problem is explaining from whence dark energy comes. Right. Expanding universe means space itself is expanding. There's more space now when you read this than there was when I wrote this. How clear is it that more is needed than that? Once the volume reached some level the amount of expansion grew to the point that gravitational bonding among galaxies was smaller than gravitational weakening to expansion and red shift. The result was a switch from decelleration to acceleration. If the math works out right for that. What is conjectured is an 'energy' to drive that expansion. Which is definitely into epicycles. More space means more mean distance. If gravitation works at C then gravity is attenuated with distance on galatic scales because there's more space for it to cross for it to have an effect. Why isn't the strength of gravity assumed to be reduced by the same amount as the red shift of observed light? What we have in-hand is an incomplete theory, both of gravitation and QM. Why is gravity exempt from QM treatment? If QM statistics don't apply to gravity then from whence does gravitation 'magically' spring into existence moving from the Planck scale up? Why should gravitation by exempt of QM statistics at all? Hm? We know from the wave particle duality of nature that both QM and GR are close approximations to truth. We know from the fact that QM has no gravity that QM is incomplete, but that's how science works in general. All knowledge is provisional in science. Some knowledge gets overturned completely (philogiston) some is close enough to the underlying truth that it probably never will be (atomic theory of chemistry and scanning electron photographs of individual atoms). We know from dark energy that GR is incomplete. QM depicts space as a foam. Sort of like having cells but cells are too simple a model to really work. Expanding universe doesn't say that galaxies are receding within space; it says that more quantum cells are forming within space to draw galaxies apart and galaxies happen to reside in specific ranges of cells. The way galaxies go faster at more distance isn't that they accelerated it's that more cells formed between here and there. Should QM explain local gravity and "more foam" it would explain the expanding universe. |
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Stargazers spot dark energy
On 22/05/2011 4:12 AM, Fred J. McCall wrote:
Alan wrote: Have they considered the possibility that, as the galaxies get further apart, their mutual gravitational attractionalso diminishes? That would also result in an increased rate of separation without resorting to any 'celestial magic'. Uh, no. To result in an 'increased rate of separation' they either need to REPEL each other or be under some other form of acceleration. Really? Couldn't the mutual gravity be holding them together? By increasing the distance between galaxies, you also reduce the mutual gravitational bond, so that would enable an increase in speed. The further apart they become, the faster they would travel away from each other. |
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Stargazers spot dark energy
::: To result in an 'increased rate of separation' they either need to
::: REPEL each other or be under some other form of acceleration. :: Really? Yes. :: Couldn't the mutual gravity be holding them together? Yes. :: By increasing the distance between galaxies, you also reduce the :: mutual gravitational bond, Yes. :: so that would enable an increase in speed. No. At most it would enable the decrease in speed to occur at a lower rate. |
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Stargazers spot dark energy
Wayne Throop wrote:
::: To result in an 'increased rate of separation' they either need to ::: REPEL each other or be under some other form of acceleration. :: Really? Yes. No. That's the deal with the expanding universe. The amount of space between here and there grows without any acceleration of either object. The question is whether the accelerating expansion is because the amount of space is growing faster or if there's now so much space between here and there that there's more of it to expand. |
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Stargazers spot dark energy
Doug Freyburger wrote:
Wayne Throop wrote: ::: To result in an 'increased rate of separation' they either need to ::: REPEL each other or be under some other form of acceleration. :: Really? Yes. No. That's the deal with the expanding universe. The amount of space between here and there grows without any acceleration of either object. The question is whether the accelerating expansion is because the amount of space is growing faster or if there's now so much space between here and there that there's more of it to expand. And I can't help but believe this is also intertwined with the 2nd Law Of Thermodynamics. We are not only expanding, we are cooling too. Dave (now colder than when I started typing this) Spain |
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Stargazers spot dark energy
David Spain wrote:
Doug Freyburger wrote: No. That's the deal with the expanding universe. The amount of space between here and there grows without any acceleration of either object. The question is whether the accelerating expansion is because the amount of space is growing faster or if there's now so much space between here and there that there's more of it to expand. And I can't help but believe this is also intertwined with the 2nd Law Of Thermodynamics. We are not only expanding, we are cooling too. That is the idea behind the frequency spectrum of the background microwave radiation. It's a black body emission spectrum that gives a specific temperature. It's part of how the age of the universe is estimated. In a sense the photons expand as the box they are in expands. It's adiabatic expansion so it's cooling expansion. Recent discussion about when life could have emerged in the universe are partially based on the temperature of the background radiation. Go far enough back and it heats biochemicals to the point of denaturing them. |
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