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How is it that a photon which is emitted...
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You are currently reading a thread in /sci/ - Science & Math

Thread replies: 7
Thread images: 1
How is it that a photon which is emitted from an object with a recession velocity greater than c can reach us at all? I understand that at first the photon is indeed receding but how can it ever reach a coordinate point where the recession velocity is less than c if it started out in one that was greater than c? Shouldn't the nature of accelerated expansion imply that it will only ever recede because distance is being "created" faster than light can traverse that distance?
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>>7812389
the answer is: dark matter.
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>>7812389

The photon cannot travel faster than the spacetime expansion, this is the postulated fate of the future universe where the sky beyond locality is completely dark.
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>>7813685
Actually its hyper refractive
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>>7812389
My assumption is that they've fucked up their calculations for such things or their understanding of the universe is flawed or incomplete.

Kinda like how they thought the Methuselah Star is older than the universe.

Physics is still mysterious. Give it a few decades and they'll sort it out.
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>>7812389
>if it started out in one that was greater than c?

It didn't. When the photon was emitted, the object was receeding from us slower than c, but is receeding from us faster than c by the time the photon arrives, so we will never see the photons emitted right now.

You've got the whole thing wrong.
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Read about conformal time, and horizons in relativity.
It the time since the universe began in t, then light that we're seeing now, should be from distance t*c away, right? But since the universe is expanding, the distance it's travelled is 3*c*d (at least in one of the cosmological models).

Also, in response to you picture: it's just the cosmological constant, a symmetry that arises in Einstein's Equations.

>>7814554
Basically this.
Thread replies: 7
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Thread DB ID: 471371



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