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What life could be like for civilizations 1 trillion years from now

phys.org

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Re: What life could be like for civilizations 1 trillion years from now

#11

Post by hsk »

montrose wrote: post #6
user5994461 wrote: post #4

Earlier quoted context omitted.

There is a theory that the universe is expanding faster and faster. At some point in the future, stars would be moving away faster than the speed of light and we couldn't ever see them again or reach them.

How could they be moving faster than the speed of light?

Because while matter cannot move faster than the speed of light the universe itself is allowed to expand faster than the speed of light. Think of the spacetime fabric stretching so fast light cannot cover the increased distance. The universe is essentially creating more distance between objects.

Another way to think of it is velocity of an object is derivative of position in space over time. If space itself is moving your position relative to it isn't changing.

Re: What life could be like for civilizations 1 trillion years from now

#13

Post by chii »

hsk wrote: post #11
montrose wrote: post #6

Earlier quoted context omitted.

How could they be moving faster than the speed of light?

Because while matter cannot move faster than the speed of light the universe itself is allowed to expand faster than the speed of light. Think of the spacetime fabric stretching so fast light cannot cover the increased distance. The universe is essentially creating more distance between objects. Another way to think of it is velocity of an object is derivative of position in space over time. If space itself is moving…

I still can't intuitively understand this. If two objects ar stationary relative to each other, the expansion implies that at some point, the distance between those two objects will increase (without either of those objects having moved).

So space is being somehow created?! What if i have a large object, will the length of that object increase? Or will it break up?

Re: What life could be like for civilizations 1 trillion years from now

#15

Post by wavedingo »

gaius wrote: post #3

all stars outside the Local Group of galaxies will no be accessible to us since they will be receding away faster than the speed of light. Can anyone explain what this means?

Due to the big bang the universe is expanding... but you’d expect the expansion to be slowing down due to the drag of gravity. However, since the 1990s we’ve observed that the universe’s expansion is accelerating - the theory is that a force called “dark energy” is causing this acceleration. If the acceleration continues, there will be a point where distant galaxies will be accelerating away from each other at the speed of light. Since light is the universe’s “speed limit”, we would not be able to travel to these galaxies with known physics because even traveling at light-speed the galaxy we’re going to would be stretching away faster. Locally, however, due to gravity, it sounds like the paper is saying we would have regions of dense galaxies that stay closer together. Islands of matter in a sea of dark energy.

Re: What life could be like for civilizations 1 trillion years from now

#16

Post by YeGoblynQueenne »

hsk wrote: post #11
montrose wrote: post #6

Earlier quoted context omitted.

How could they be moving faster than the speed of light?

Because while matter cannot move faster than the speed of light the universe itself is allowed to expand faster than the speed of light. Think of the spacetime fabric stretching so fast light cannot cover the increased distance. The universe is essentially creating more distance between objects. Another way to think of it is velocity of an object is derivative of position in space over time. If space itself is moving…

If I understand this correctly, you're talking about something similar to Star Trek's Warp Drive (or the Alcubierre drive, for something less fictional). Instead of stars and galaxies moving at the speed of light, the space around them expands and the expansion accelerates at a rate that will eventually make the speed of expansion larger than the speed of light. Or in other words, stars and galaxies will continue to move at their sub-luminar speed, but the space in which they exist will expand so fast that the expansion will cause the distance between them to increase at such a rate that light will not be able to keep up.

[Edit: and, er, all that has something to do with dark energy?]

OK, but in that case, and if we still exist as a technological civilisation at that time (very doubtful) we might be able to use the effect for our own benefit. By building warp drives and er, not-quite-travelling faster than light, by expanding space around a ship, etc.

Re: What life could be like for civilizations 1 trillion years from now

#17

Post by oooooof »

wavedingo wrote: post #15
gaius wrote: post #3

all stars outside the Local Group of galaxies will no be accessible to us since they will be receding away faster than the speed of light. Can anyone explain what this means?

Due to the big bang the universe is expanding... but you’d expect the expansion to be slowing down due to the drag of gravity. However, since the 1990s we’ve observed that the universe’s expansion is accelerating - the theory is that a force called “dark energy” is causing this acceleration. If the acceleration continues, there will be a point where distant galaxies will be accelerating away from each other at the sp…

The idea that humanity will ever travel even to the nearest star is pure fiction.

Anyone who thinks otherwise just fails to grasp the distances involved. They are so large as to be beyond understanding.

Re: What life could be like for civilizations 1 trillion years from now

#18

Post by davnicwil »

viach wrote: post #12

Then, there will be a post on HN about it, marked [2018 FE (First Era)]. "Ancients knew all this would happen [2018 FE]"

And below that, a post about how this will be the year of Linux on the desktop?

Sorry, couldn't resist :-)

Re: What life could be like for civilizations 1 trillion years from now

#19

Post by oooooof »

a3n wrote: post #2

I think tools 1 trillion years from now that stumble across that headline will wonder what humanity was.

Or indeed why any sentient alien should care.

“Apes became conscious, heated up and destroyed their environment, forced back to wilderness, evolved out. Meh... who cares.”

Re: What life could be like for civilizations 1 trillion years from now

#20

Post by OscarCunningham »

This goes together nicely with the Aestivation Hypothesis (https://arxiv.org/abs/1705.03394).

If a civilisation puts itself on hold for a trillion years, just waiting around doing nothing, then when it wakes up the universe is much colder and it can do computations 10^30 times more efficiently. If the civilization consists of minds running on computers then they've increased their own lifespans by the same factor.

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