The expansion of the universe is a phenomenon wherein, at scales much larger than galaxies, the distance between objects grows over time. This phenomenon is often described as "expansion of space", although there is no difference between space expanding and objects moving apart.
Questions tagged [space-expansion]
1972 questions
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Furthest distance I can travel and still be able to get back to Earth?
The expansion of the universe currently makes anything beyond ~16 billion light years away from us unreachable (because of the cosmic event horizon). This makes less than $3\%$ of the observable universe reachable, and even less of it available for…
potato
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2
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How distant is the origin of oldest space radiation reaching us?
A comment to my question straightens out a misconception.
That places the furthest theoretically observable edge of universe at 13.798 bln light years away - this is how long light would take to reach us from there, and there were no light sources…
SF.
- 2,988
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Does the expansion of the universe make time pass faster?
Afaik. mass slows down time, while expansion means that the universe will be less dense in mass. Does that mean that time will go faster everywhere?
inf3rno
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2 answers
Does the expansion of space cause light to lose energy, or is it the other way around?
I am just starting Astronomy and have enjoyed reading about it. The expansion of space, the determination of the Hubble constant by looking at red-shifts, e.t.c. and it has made me wonder, is light red-shifted because of the expansion of space, or…
2
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By what means is space expanding?
By what means is space expanding?
Can we reproduce the conditions in a laboratory experiment to observe "man made" space expansion?
scm
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Is the 74.2km/sec per megaparsec accidental?
The rate of expansion of the universe is 74.2km/sec per megaparsec
The age of the universe is 13.798 bln years
That places the furthest theoretically observable edge of universe at 13.798 bln light years away - this is how long light would take to…
SF.
- 2,988
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0 answers
Expansion of space
Possible Duplicate:
spacetime expansion and universe expansion?
So I've heard that space is expanding very quickly and that the redshift we see when we look at other galaxies is evidence of this. But why doesn't this expansion affect orbits of…
John
- 2,808
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If we can see a galaxy can that galaxy see us?
This is a question about the properties of the expansion of the universe. I can't say it any better than: If we observe a primordial galaxy that existed soon after the Big Bang, does it follow that the same galaxy, at roughly the same number of…
Lucy Meadow
- 799
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Virtual particle production in space-time.
Are virtual particles created within existing space-time, or do they create new space-time for them to occupy?
0
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If the universe expands does spacetime,dark energy,dark matter,gravity expands also?
If the universe expands does spacetime,dark energy,dark matter,gravity expands also ?
Do forces,energy/matter expand with the universe also ?
When we say that the universe is expanding ,what is actually expanding ?
jim101
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How to generate space?
Space is its own existing thing as is matter and energy. We can turn Matter into energy and we can harness energy for motion so... how can we generate space?
because if we could generate space, we could do so "faster" than space is collapsing toward…
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When calculating the red shift of a star, what does the value mean?
Is red shift (z) given as a velocity, or a constant? If it's a constant, what does the given value mean?
Kw153
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Is the cosmic acceleration changing it's value in time?
I understand that the cosmic acceleration (the acceleration of the expanding Universe) is estimated to have a value of something like $10^{-15} m/sec^2/Mpsec$.
My question is: how much this value changed and will change in time? What was the value…
Joe Jobs
- 233
0
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1 answer
The Scale Factor During The Planck Epoch
If the scale factor $a(t)$ is 0 at the start of the universe, what would the scale factor at the end of the Planck epoch (t=Tp) be?
Ringo Hendrix
- 521
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Ripples from the big bang
A pebble dropped in a pond creates ripples of concentric circles. Each larger circle having infinitely more points than the smaller ones inside. If we use any arbitrary size for the unit "point" with each point existing on the end of its own radius…
