Religion and Ethics Forum
General Category => Science and Technology => Topic started by: Shaker on March 04, 2016, 11:29:31 AM
-
... since that amounts to the same thing in this case:
https://goo.gl/E0b4iZ
By pushing NASA’s Hubble Space Telescope to its limits, an international team of astronomers has shattered the cosmic distance record by measuring the farthest galaxy ever seen in the universe. This surprisingly bright infant galaxy, named GN-z11, is seen as it was 13.4 billion years in the past, just 400 million years after the Big Bang. GN-z11 is located in the direction of the constellation of Ursa Major.
-
At how many times the speed of light has space expanded since the Big Bang?
-
At how many times the speed of light has space expanded since the Big Bang?
If you can't go faster than light, then I guess it can only expand at that speed.
:-\
-
At how many times the speed of light has space expanded since the Big Bang?
It may be expanding now faster than the speed of light.
Why does this matter as we know it is increasing and will eventually expand faster than light speed.
-
It may be expanding now faster than the speed of light.
Why does this matter as we know it is increasing and will eventually expand faster than light speed.
Will it?
I thought nothing could go faster than the speed of light.?
-
Will it?
I thought nothing could go faster than the speed of light.?
Nothing can travel through space faster than that.
The expansion is not travelling through space and has no limit. In fact I do not think it has any speed to speak of as we define distance travelled in space in a given time. It is not travelling THROUGH space. It is making more space.
Some galaxies are travelling away from us FTL, but only due to expansion.
-
Nothing can travel through space faster than that.
The expansion is not travelling through space and has no limit. In fact I do not think it has any speed to speak of as we define distance travelled in space in a given time. It is not travelling THROUGH space. It is making more space.
Some galaxies are travelling away from us FTL, but only due to expansion.
Ok thanks :)
-
It may be expanding now faster than the speed of light.
Why does this matter as we know it is increasing and will eventually expand faster than light speed.
My point is that....at the time of the Big Bang, space was small. All the matter that now makes up the earth and sun and we humans etc. was present at that very spot (Singularity). Over 13.7 billion years, space has expanded such that we are where we are now. So...why should it take light emanating from the BB, 13.7 billions years to catch up with us?
-
... since that amounts to the same thing in this case:
https://goo.gl/E0b4iZ
Was that enough time for a galaxy to form?
What would they do if they saw one 25 billion light years away?
-
Was that enough time for a galaxy to form?
Yes.
What would they do if they saw one 25 billion light years away?
There would be a whole lot of rewriting of astrophysics and cosmology and Nobel Prizes dished out like Smarties :)
-
My point is that....at the time of the Big Bang, space was small. All the matter that now makes up the earth and sun and we humans etc. was present at that very spot (Singularity). Over 13.7 billion years, space has expanded such that we are where we are now. So...why should it take light emanating from the BB, 13.7 billions years to catch up with us?
That's due to inflation. It's only now that the light is catching up to us since inflation stopped. Inflation expanded the universe many times faster than the light could travel.
-
That's due to inflation. It's only now that the light is catching up to us since inflation stopped. Inflation expanded the universe many times faster than the light could travel.
Thanks.... splashscuba!
-
That's due to inflation. It's only now that the light is catching up to us since inflation stopped. Inflation expanded the universe many times faster than the light could travel.
I find this very difficult to visualise, but it seems to indicate that the expansion of the universe is gradually slowing down and will eventually stop and start contracting. Is that the way it is?
-
I find this very difficult to visualise, but it seems to indicate that the expansion of the universe is gradually slowing down and will eventually stop and start contracting. Is that the way it is?
No. Looks like it's expanding at an ever increasing rate. See dark energy.
-
No. Looks like it's expanding at an ever increasing rate. See dark energy.
But you said inflation stopped. :-
"That's due to inflation. It's only now that the light is catching up to us since inflation stopped. Inflation expanded the universe many times faster than the light could travel."
? ? ?
-
Two different things, Len. The inflationary era was a very, very, very brief period of incredibly rapid expansion at the birth of the universe which inflated it at a truly colossal rate, which quickly came to an end to leave behind the (comparatively speaking) rather more sedate expansion of space that we see now.
The Wikipedia page on inflation is a bit on the technical side; this is one of the simpler explanations if you feel like having a go: http://goo.gl/1evud8
-
Two different things, Len. The inflationary era was a very, very, very brief period of incredibly rapid expansion at the birth of the universe which inflated it at a truly colossal rate, which quickly came to an end to leave behind the (comparatively speaking) rather more sedate expansion of space that we see now.
? ? ?
So it initially expanded very fast, then slowed down allowing the original light to catch up with us, and then started to get faster again?
What on earth could make that happen?
-
? ? ?
So it initially expanded very fast, then slowed down allowing the original light to catch up with us, and then started to get faster again?
What on earth could make that happen?
The expansion of the universe has been observed to be accelerating - nobody knows why. For the time being we have to use terms such as dark energy which are freely acknowledged to be placeholders for our current state of ignorance, until such a time as we get more data in.
-
The expansion of the universe has been observed to be accelerating - nobody knows why. For the time being we have to use terms such as dark energy which are freely acknowledged to be placeholders for our current state of ignorance, until such a time as we get more data in.
Oh dear, that sounds like encouragement for Alan! :(
-
Oh dear, that sounds like encouragement for Alan! :(
Not really I thought this was common knowledge, but I accept that I take an interest in this sort of thing.
It seems that the acceleration will continue to increase and the universe will appear empty. Anyone around then to look in the night sky will see total blackness apart from the star that keeps them alive. All other galaxies will be so far away that light from them can NEVER reach them.
-
Not really I thought this was common knowledge, but I accept that I take an interest in this sort of thing.
It seems that the acceleration will continue to increase and the universe will appear empty. Anyone around then to look in the night sky will see total blackness apart from the star that keeps them alive. All other galaxies will be so far away that light from them can NEVER reach them.
Isn't the idea then is that the universe will be so large then a usually statistically improbable reversal in entropy becomes likely that a new big bang occurs?
-
Not really I thought this was common knowledge, but I accept that I take an interest in this sort of thing.
It seems that the acceleration will continue to increase and the universe will appear empty. Anyone around then to look in the night sky will see total blackness apart from the star that keeps them alive. All other galaxies will be so far away that light from them can NEVER reach them.
Curiouser and curiouser! I can run with the idea that the expansion is gradually slowing down (which seems logical to me) but speeding up - what on earth could be a theory to cover that?
-
Curiouser and curiouser! I can run with the idea that the expansion is gradually slowing down (which seems logical to me) but speeding up - what on earth could be a theory to cover that?
We don't know! Dark energy has been hypothesised as a repulsive force driving the expansion faster. It's all we can do for the time being.
-
We don't know! Dark energy has been hypothesised as a repulsive force driving the expansion faster. It's all we can do for the time being.
A sort of anti-gravity?
-
A sort of anti-gravity?
Well, sort of, very loosely speaking, insofar as it's proposed as a repulsive force a little like the poles of magnets.
-
Well, sort of, very loosely speaking, insofar as it's proposed as a repulsive force a little like the poles of magnets.
And obviously stronger than gravity.
-
Indeed.
That's not difficult. It seems counter-intuitive because living on a huge mass our lives are dominated by it, but gravity, though it has an infinite range, is the weakest of the fundamental forces of nature - very very very feeble indeed.
-
Curiouser and curiouser! I can run with the idea that the expansion is gradually slowing down (which seems logical to me) but speeding up - what on earth could be a theory to cover that?
Dark Energy.
Another phrase for do not know.
-
And obviously stronger than gravity.
Gravity is very very weak.
Think about it, you can lift something despite the whole Earth pulling against you.
-
Gravity is very very weak.
Think about it, you can lift something despite the whole Earth pulling against you.
It seems very strong to me when I fall down. :(
-
It seems very strong to me when I fall down. :(
But throughout your life, Len, how much of the time have you spent 'falling down' and how long have you spent flat on the floor unable to get up?
-
But throughout your life, Len, how much of the time have you spent 'falling down' and how long have you spent flat on the floor unable to get up?
All forms of life have evolved muscles strong enough to cope with gravity. :)
-
All forms of life have evolved muscles strong enough to cope with gravity. :)
And your muscles can pull things way from the Earth even though the entire Earth is trying to stop you.
-
And your muscles can pull things way from the Earth even though the entire Earth is trying to stop you.
Well whatever this anti-gravity thing is, it is clearly weaker than gravity or we would all fly away for ever. How come it is strong enough to push the universe apart but not strong enough to push me away from earth?
-
Well whatever this anti-gravity thing is, it is clearly weaker than gravity or we would all fly away for ever. How come it is strong enough to push the universe apart but not strong enough to push me away from earth?
I think it has something to do with space itself. The more space there is the more it accelerates.
It is stronger than gravity over large distances, and this is why the universe is not only expanding, but expanding faster and faster against the pull of gravity. Gravity has already lost the battle against this 'Dark Energy'.
-
I think it has something to do with space itself. The more space there is the more it accelerates.
It is stronger than gravity over large distances, and this is why the universe is not only expanding, but expanding faster and faster against the pull of gravity. Gravity has already lost the battle against this 'Dark Energy'.
I don't understand the expression 'the more space there is'. Space doesn't have dimensions, does it? ???
-
The universe is expanding, remember, Len. The point about dark energy - the hypothesis, anyway - that B. Rat was making is that although it's so weak as to be undetectable by curent technology, the more the universe expands the more of it there is (dark energy, I mean, as well as the universe) and at those sort of unimaginable scales it's accelerating the expansion.
-
... the more the universe expands the more of it there is (dark energy, I mean, as well as the universe) and at those sort of unimaginable scales it's accelerating the expansion.
But if you are saying there is more and more 'dark energy', where is it coming from?
-
That's what nobody knows!
-
But if you are saying there is more and more 'dark energy', where is it coming from?
The space itself contains the energy. More space, more energy.
The energy could be in the quantum fluctuations. We know that the energy in a vacuum is zero ON AVERAGE, but it can have some energy for a small amount of time.
It seems that as long as the universe has not noticed the positive energy because it was there for such a short period, it does not care. As long as the energy in the vacuum is mostly zero when it looks, all is well.
-
The space itself contains the energy. More space, more energy.
The energy could be in the quantum fluctuations. We know that the energy in a vacuum is zero ON AVERAGE, but it can have some energy for a small amount of time.
It seems that as long as the universe has not noticed the positive energy because it was there for such a short period, it does not care. As long as the energy in the vacuum is mostly zero when it looks, all is well.
I have to give up, I'm afraid, it's more than my old brain can get round! :(
-
By pushing NASA’s Hubble Space Telescope to its limits, an international team of astronomers has shattered the cosmic distance record by measuring the farthest galaxy ever seen in the universe. This surprisingly bright infant galaxy, named GN-z11, is seen as it was 13.4 billion years in the past, just 400 million years after the Big Bang. GN-z11 is located in the direction of the constellation of Ursa Major.
They're gonna have to work on explaining how it could come to contain so many stars in such a "short" time. (400 my)
-
They're gonna have to work on explaining how it could come to contain so many stars in such a "short" time. (400 my)
Not really - it varies depending on the type of star of course but a proto-star can form in 100,000 years and achieve fusion (i.e. switch on) in 10 million years.
In other words, plenty of time.
-
I have to give up, I'm afraid, it's more than my old brain can get round! :(
Don't put yourself down.
No one else knows either.