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CatastropheJohn t1_j1goarj wrote

Reply to comment by enutz777 in Did you know it will still take 46 billion years to cross the universe at the speed of light? 65 mph = 4.8 * 10^17 years! by NotAndroid545

But… but… I’m told nothing can move that fast.

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enutz777 t1_j1goote wrote

That’s the neat thing… it isn’t. Space itself is expanding and since space is, you know, like, really big, all that expansion adds up to faster than light can move through space.

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diogenes_shadow t1_j1gsoxk wrote

But the CMB photons are from the big bang itself. And they have been traveling ~14billion years.

If your yardstick changes size you can make any numbers you want come out.

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awesomewealthylife t1_j1hw09h wrote

Yeah, galaxies 18b light years away have space expanding between us and them at a rate thats faster than the speed of light without breaking the speed of light, its the space thats changing. There’s so much space between here and there that the expansion causes the effect, its not a speed limit issue.

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diogenes_shadow t1_j1iz9q0 wrote

But the photons from the big bang boundary have been traveling at the speed of light for 14 billion years and are arriving here today. The CMB comes from a perfect sphere around us, visible in every direction, with all the matter in the universe inside that sphere. We see the entire sphere of CMB and yet fools talk about the unobservable parts of the universe.

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awesomewealthylife t1_j1jjzq0 wrote

And how say you to the galaxies that are 40b lightyears away?

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diogenes_shadow t1_j1jzahg wrote

Once again, the speed of light is a constant to all observers. That makes it a terrible yardstick, because different observers see different things.

As an earth based human I see the big bang coming from all directions because it was 14 billion years ago in every direction! I know the mass of the universe is contained within that still expanding sphere.

I also know that every other observer (who uses light) from their planet will also see a perfect sphere around their own planet. This is a fundamental flaw in light years as a yardstick.

Calculations for other observers may show other things but in the universe I see, two galaxies in opposite directions from earth can be at most twice the age of the universe apart. Note: that number is climbing at 2*C.

And the part that hurts my brain is that each of those two ultimate polar opposite galaxies will also see the CMB as a sphere around them.

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