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by gangorgasm 675 days ago
Appreciated. Big distance

I have difficulty conceptualizing "distance over time ... over [huge] distance"

I guess it means "chunks about so [megaparsecs] large are moving [themselves] at a speed of so many Km. per second" but I could be wrong
2 comments
tyfon 675 days ago
The measurement for expansion is linear with distance, so two spots one Mpc from another moves away front each other at 67.4 km/s while two spots two Mpcs from each other moves at 134.8km/s. This means the expansion is accelerating and some parts of the now visible universe will eventually move away from us faster than the speed of light resulting in them disappearing from our view.

The distances, time and speeds are indeed very hard to comprehend from our usual references :)

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gangorgasm 675 days ago
It's crazy that some parts of the universe will actually for all purposes vanish

Thanks for taking time to break it all down

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daedrdev 675 days ago
At some point there will only be the galaxies in our local group visible, it's interesting to imagine a future civilization only having such a limited universe to view.
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ryandrake 675 days ago
Doesn't this mean that on a long enough time frame, an observer anywhere in the universe won't be able to see anything because everything else in the universe is too far away to be visible?
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shagie 675 days ago
Simply - yes. Furthermore, civilizations that arise in that era of the universe will likely have a different cosmology than what we are able to understand today. If you could only see the galaxy that you are in, you wouldn't be able to see galaxies that were forming shortly after the Big Bang, or be able to use supernovas in other galaxies to measure the scale of the universe.

Kurzgesagt did a video on that - TRUE Limits Of Humanity – The Final Border We Will Never Cross https://youtu.be/uzkD5SeuwzM

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gangorgasm 675 days ago
>> civilizations that arise in that era of the universe will likely have a different cosmology than what we are able to understand today.

That is just mind-boggling

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layer8 675 days ago
It means that a chunk of space with length 1 megaparsec will be 67.4 km longer a second later. If you divide that new length by the old length, you get the factor by which space expands each second. It’s a very small factor (i.e. very close to 1), but there are also many seconds.
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