bendvis t1_j1gpibe wrote
Reply to comment by polovstiandances 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
The speed at which you can stretch a balloon’s surface and the speed at which an ant walks across the balloon’s surface are distinct and separate things that aren’t related.
The same is true of the speed at which light (or gravitational waves or information in general) propagates through space and the space it’s propagating through. They’re not related.
Keep in mind that space expanding happens ‘faster’ on bigger scales. If 10 cm of balloon distance expands to 11 cm over the course of a minute, then the points that were 10 cm apart are moving away from each other at 1 cm/minute, even though neither point is moving across the balloon in its own frame of reference. If the balloon were enormous with two points 10 light years apart and it expands at the same rate, they’d be moving apart at 1 light year per minute - much faster than the speed of light.
polovstiandances t1_j1gpzu1 wrote
Ok this makes sense. But still doesn’t touch on how fast spade can expand, and whether there is a max limit to that. But I guess you’re saying that yeah, space still cannot expand faster than a certain rate, it’s just that the rate it expands informs a different understanding on the time plane. But space cannot expand faster than the speed of light, right? What I mean is just the raw rate at which the universe is expanding must be some function of an expansion rate even if it causes the amount of total space to exceed the distance achievable by the speed of light, right?
bendvis t1_j1gqo13 wrote
According to one theory, during a time called Inflation, space expanded really fast. The volume of space expanded 10^78 times larger in 10^-32 seconds. That was way faster than the speed of light. This super rapid expansion explains why the cosmic background radiation is so nearly perfectly even - because at that time in the early universe, it was all in one point. If there is a limit, it would have to be faster than that.
polovstiandances t1_j1gqx97 wrote
That’s fucking nuts. I need to know more. Thanks.
bendvis t1_j1gs98d wrote
My wife and I just discovered a really well done YouTube channel called Astrum. Their video on black holes is fascinating and covers this stuff in a clear and straightforward way. Highly recommended!
f_d t1_j1gysd5 wrote
>This super rapid expansion explains why the cosmic background radiation is so nearly perfectly even - because at that time in the early universe, it was all in one point.
It wasn't necessarily in one point, it was just extremely dense and homogeneous. Space could have been infinite even when everything was packed together tightly.
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