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brknsoul t1_isjuu2d wrote

Imagine a completely empty universe, in which you place two stationary objects. Given enough time, these two objects will meet, no matter how far apart they are.

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Morbos1000 t1_isjx59g wrote

That is not the universe we are in however. The universe is expanding at such a rate that objects outside the visible part of the universe are expanding away from us faster than causality, meaning their gravitational influence never reaches us.

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[deleted] t1_isjy2ky wrote

[removed]

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UAPDATASEEKER t1_isjy768 wrote

I know dark energy is the expanding source but just pointing out how the current model is going to fail eventually if we don't find dark matter.

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ski233 t1_isk1bb0 wrote

We don’t know this for certain that there are any parts of the universe expanding faster than the speed of light. That is just a theory.

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BridgeOnColours t1_isk9dz3 wrote

However there's a force that makes light or electromagnetic wavelengths stretch which can't be explained by any other means but space expanding at a rate faster than light

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ski233 t1_isk9jq8 wrote

Space is expanding. But not faster than light in any way/place we have observed.

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BridgeOnColours t1_iskbwn9 wrote

The reason we need JWST instead of Hubble telescope to see extremely far objects is the reason why your statement is wrong

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ski233 t1_iskc265 wrote

If the distant objects were expanding away from us faster than the speed of light then we wouldnt be able to observe them.

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BridgeOnColours t1_iskcrcu wrote

But we are able to observe them, because JWST is able to picture objects which wavelengths have been stretched into the infrared wavelengths, making it unobservable to Hubble, which can mostly detect visible light and some UV light.

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Ape_Togetha_Strong t1_islj6l3 wrote

We cannot observe things that are expanding away from us faster than the speed of light.

We can only observe the past of objects that are currently expanding away from us faster than light, because the evidence of that past was emitted before the object was expanding away faster than light.

That is the light that is highly red-shifted.

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MisterET t1_islgwk5 wrote

That's exactly true! That's called the observable universe, which is smaller than the actual universe. Our observable universe is expanding at the speed of light, but objects already outside of that bubble will NEVER be inside that bubble. They are forever outside our observable universe.

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MisterET t1_islgnlf wrote

Think about the implications of what you just said though. If space is expanding, and space is also very, very large, then there exists two points so far apart that they are expanding away from each other faster than the speed of light.

You don't even need to observe it specifically. If space is in fact expanding, that expansion is cumulative, and it necessarily exceeds c once you get enough space between points.

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Ape_Togetha_Strong t1_iska6mb wrote

The majority of the observable universe is expanding away from us faster than C. The distance at which the expansion is faster than C is only around 14.5 billion lightyears, and the radius of the observable universe is ~46billion.

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Jamandi_Aldori t1_iskmhhy wrote

>We don’t know this for certain that there are any parts of the universe expanding faster than the speed of light.

The statement he made does not require the universe to be expanding faster than light. Just expanding faster than the rate of acceleration that the gravitational influence of distant objects would have.

We know this it to be true, objectively, because we can measure and observe the relativistic red-shift of distance galaxies as they move away from us at various fractions of the speed of light.

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ski233 t1_isksz60 wrote

What he said was “faster then causality” ie the speed of light.

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