Hubble Space Telescope breaks time/distance record

[Leonard James]

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.

[Shaker]

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.

[BeRational]

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.

[BeRational]

And obviously stronger than gravity.

Gravity is very very weak.

Think about it, you can lift something despite the whole Earth pulling against you.

[Leonard James]

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. 

[Hope]

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?

[Leonard James]

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. 

[BeRational]

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.

[Leonard James]

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?

[BeRational]

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'.

[Leonard James]

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? 

[Shaker]

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.

[Leonard James]

... 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?

[Shaker]

That's what nobody knows!

[BeRational]

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.

[Leonard James]

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!

[Spud]

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)

[Shaker]

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.

[BeRational]

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.