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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?
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.
I think tools 1 trillion years from now that stumble across that headline will wonder what humanity was.
Then like archaeologists everywhere will conclude it was of religious significance.
Earlier quoted context omitted.
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?
If the cosmological constant were much larger than it is, atoms would have never formed at all.
Errr. I think by 2400 we’ve got every chance of living in the ruins of a past grand human civilization. Trillion is nice sci fi. 10,000 years in the future with any recognizable civilization is even more of a stretch.
Errr. I think by 2400 we’ve got every chance of living in the ruins of a past grand human civilization. Trillion is nice sci fi. 10,000 years in the future with any recognizable civilization is even more of a stretch.
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?
Instead, new space is being created between all objects. This can cause the distance between two objects to increase "faster" than the speed of light, without either of the objects actually moving.
Earlier quoted context omitted.
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…
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.
Earlier quoted context omitted.
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.
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.
So would the light from those stars also be moving outward faster than the speed of light?