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If the universe is expanding, are we expanding too?

Author: autokill

Score: 5

Comments: 10

Date: 2020-11-06 22:24:31

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srtjstjsj wrote at 2020-11-07 02:49:12:

Veritasium recently did a video on this

https://www.veritasium.com/videos/2020/10/23/do-you-expand-w...

emerged wrote at 2020-11-07 02:59:55:

Did galaxies evolve much quicker billions of years ago since expansion hadn't yet pulled them as far apart? In other words, the further back in time you go did matter tend to interact much more frequently so in some sense the interaction-time of the universe is much longer than the actual number of years?

762236 wrote at 2020-11-07 02:50:03:

The wild thing to me, assuming I understand it correctly, is that the expansion speed can exceed the speed of light.

cdumler wrote at 2020-11-07 03:07:20:

You correct, but in the details. Travelling through space is limited to the speed of causality (the speed any massless particle travels) but space between itself is not limited to any particular speed.

Think of it this way: A balloon is space and the speed of sound is the limit at which waves can travel across it. This normal for sound waves. If every bit of the balloon expanded at 1 inch per second, a small balloon would be getting bigger, but wouldn't exceed the speed of sound. A sound wave will outrace the expansion.

Once the balloon as expanded to about 2500 feet in diameter, the expansion along the balloon will be greater than the speed of sound. A sound wave will never make to the other side. That said, no one place is expanding more than 1 inch per second. Nothing in part violates the speed of sound.

k_sze wrote at 2020-11-07 03:05:28:

Yep. That’s why we talk about the _observable_ universe. Objects outside the radius of the observable universe are moving away from us so quickly that any light or gravitational effect from those objects have no chance of reaching us any longer.

drummer wrote at 2020-11-07 03:17:12:

All organisms expand or grow. The universe is an organism. The earth is an organism. And it is growing. Etc.

EdgarVerona wrote at 2020-11-07 03:17:14:

I just ate enough thai food for 3 people so I'm pretty sure I am at least

keanebean86 wrote at 2020-11-07 03:22:18:

If it makes you feel any better according to relativity you're now slight more attractive.

fargle wrote at 2020-11-07 04:07:19:

I'm definitely expanding. Beer and Cheezits. Probably a minor gravitational anomaly at this point, but still.

rrivers wrote at 2020-11-07 02:56:27:

Yes if we consider the universal as information and our relationships to it as receivers. We've been expanding our time experience for millennia and will continue to so as long we continue to imagine and create.