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Originally Posted by Bjoern
Why do you think one needs to make up a fancy term for something which has been known for about 80 years, and which has been studied theoretically for at least 20 years now?
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My first request, Bjoern, is that you not rush to judgement. The mainstream has overlooked something; it would behoove you to slow down and take a look at what I'm suggesting has been overlooked.
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Originally Posted by Bjoern
… How does contraction release energy, and why does expansion require energy?
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If you consider the simplest gravitational system—two bodies orbiting each other—the system does not change without the input or loss of energy. If the system contracts, it must somehow lose energy; if the system expands, it must somehow gain energy.
If you consider gravitational systems more complex that two bodies, one part of the system—generally—contracts (releases energy) while another part expands (gains energy). Consider a 3-body system: the earth; a low-earth satellite and the moon. The satellite spirals in, losing gravitational potential energy (GPE), which is radiated away as heat; the moon, on the other hand, spirals away, gaining GPE. Thus, one part of this 3-body system contracts, while the other part expands.
So to answer the first part:
How does contraction release energy? It does so via electromagnetic radiation: that is, local GPE is radiated away. To answer the 2nd part: Why does expansion require energy? For the same reason going up stairs requires energy.
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Originally Posted by Bjoern
Why don't you convert both to a relative rate of change per second? Would make much more sense!
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It does not matter which units are used. If 10 mph is faster than 7 mph, it will still be faster in m/s, or whatever units you use. The answer does not depend upon the units: the universe is contracting faster than it is expanding.
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Originally Posted by Bjoern
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Originally Posted by Peter Wilson
Rate of contraction (estimate post 33): = 2E-8 j/kg/s (2 x 10^(-8)).
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That post and that number are about the energy emitted in the form of radiation, not about a "rate of contraction". Additionally, in that post you said that this energy output powers the expansion, not the contraction. |
Associated with contraction is the release of energy. Thus, the rate of energy loss is equivalent to the rate of contraction. The satellite orbiting earth and losing GPE as it spirals in loses energy at the rate at which it radiates away GPE. The satellite’s orbit is contracting at the rate it is radiating away energy. Virtually all “local” gravitational systems behave this way: they contract at the rate at which they radiate away energy.
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Originally Posted by Bjoern
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Originally Posted by Peter Wilson
Rate of expansion (estimate post 256): = 6E-9 j/kg/s
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That post is about the power required to separate two large "clumps" (5 Mpc), not about a "rate of expansion".
Calling these numbers "rate of contraction/expansion" makes little sense - you yourself pointed out already that such rates are usually given in the unit 1/s (or something equivalent). If you converted the numbers above to that unit somehow, please tell me where I can find the relevant post. |
Expanding two bodies in orbit, at a given rate, is an approximation for expanding an infinite number of bodies, at the same rate. If you do the calculation on a per-body basis (i.e. per kilogram), the 2-body approximation is in the same ballpark as the infinite-body system.
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I don't see what the "rate of contraction" should have to do with "the rate at which GPE is being converted to radiant energy", and what "rate of expansion" should have to do with "rate at which radiant energy is converted into GPE", and what both have to do with the power required to separate two 5 Mpc large clumps of matter. And I didn't find anything clarifying about that in the thread you mention here. It is quite long, so I perhaps missed the relevant post; could you please tell me which you meant?
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When you do see it, it will all add up.
If you look around, starting with yourself, you will see every “local” entity is in orbit around a local center-of-gravity. Yet a body orbiting another body does nothing without input or output of energy (see above). Think about a cloud of gas, contracting to form a star. The cloud of gas is orbiting about a center of gravity. There is a gravitational force inward; there is a gas-pressure force acting outwards. These two forces are in perfect balance…except for the radiant losses. With every photon radiated away, the gas cloud loses a little energy, and contracts a little bit. Therefore, the cloud of gas contracts at the rate at which it radiates away energy.