Dark Energy ........ WTF ???????

[driverrob]

Has anyone tried reading the latest BBC article: http://www.bbc.co.uk/news/science-environment-2030... ?

I'm a physicist and it's giving me a headache.

e.g.
"So, dark energy is something that increases with time. As the Universe expands, it gives us more space and therefore more energy, and at some point dark energy takes over from gravity to end the deceleration and drive an acceleration," the Portsmouth University, UK, researcher told BBC News.

Seems to me he's saying the Universe is not only a perpetual motion machine but that it self-generates energy from nothing by forcing itself to expand !!!!!!!!!!

.................
It just got worse on BBC2 - "vacuum energy" being discussed.

I need a lie-down.

[Pints]

I thought this fella was responsible for dark energy.

[RealSquirrels]

Vacuum energy is real and measurable

[Gene Vincent]

A full explanation of Dark Energy has been on here for months, you should trace back some of the threads here in the Science! forum, we're way ahead of all the media.

[Terminator X]

Perhaps a dense post but isn't the energy in the universe static ie never goes down or up?

TX.

[Speedy1995]

From what i gather the universe is an explosion that is on going and unlike an explosion on earth that is dapened by matter there is nothing to dampen the universe explosion because its the universe and theres nothing else.

sorry for any poor spelling

[AJI]

One fundamental issue with 'dark energy'/'vacuum energy' that I don't get is if two bodies move apart they create a 'space' or 'vacuum' between them, this is supposedly then filled with energy and the more the two bodies separate more energy is created.........
Does this not infringe the laws of energy conservation?
ie. energy can not be created or destroyed, it can only be transferred from one form to another.

sorry just seen this.......

Gene Vincent said:

A full explanation of Dark Energy has been on here for months, you should trace back some of the threads here in the Science! forum, we're way ahead of all the media.

Off to try and find it.....

Edited by AJI on Wednesday 14th November 11:22

[Gene Vincent]

Here:-

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Read the whole thing, vacuum energy and Dark Energy expansion mechanism is explained.

[Jandywa]

I'd always thought that it was a property of space so to speak. So with space expanding, more and more dark energy is being 'formed'

[Gene Vincent]

Terminator X said:

Perhaps a dense post but isn't the energy in the universe static ie never goes down or up?

TX.

Indeed.

Dark energy is not energy in the terms we relate to readily, for a start it is not one thing, it is at least two things, first the non-causal spontaneity of additional space, which is an energy but fairly strange to say the least, then it is also some form of energy that does not do work or interact across the quantum fields, we also have no idea of the intricacies of the second mechanism but are fairly certain that it exists.

No question is daft or dense in this field, just look how your post has prompted an answer for you and Jandywa.

Thoughtful consideration is never foolish, it is the exact opposite.

Edited by Gene Vincent on Friday 16th November 21:10

[thegherkin]

Okay, my apologies for bumping up an old thread, but there are some misconceptions here that need to be addressed.

"Dark energy" is just a placeholder term we use to describe whatever-it-is that is propagates the expansion of spacetime. It caused the Big Bang to start, it caused the universe to inflate, it caused all densities to drop to the point where stable matter could exist, and it's still in effect today, increasing all distances everywhere. But what is it? We haven't a clue. We've given it a name — dark energy — just so we can have educated discussions.

Now, onto conservation of energy, which a few people further up mentioned. All our conservation laws derive from Nöther's theorem. If you go through the maths, what you'll find is that energy is only conserved when the lagrangian of a system is time-translation invariant, and that when that symmetry is broken energy is no longer guaranteed to be conserved. In other words, energy is locally conserved. Absolutely. But across the universe? Not guaranteed. I've certainly seen solutions to the field equation in which energy is not conserved.

[Gene Vincent]

thegherkin said:

"Dark energy" is just a placeholder term we use to describe whatever-it-is that is propagates the expansion of spacetime. It caused the Big Bang to start, it caused the universe to inflate, it caused all densities to drop to the point where stable matter could exist, and it's still in effect today, increasing all distances everywhere. But what is it? We haven't a clue. We've given it a name — dark energy — just so we can have educated discussions.

Now, onto conservation of energy, which a few people further up mentioned. All our conservation laws derive from Nöther's theorem. If you go through the maths, what you'll find is that energy is only conserved when the lagrangian of a system is time-translation invariant, and that when that symmetry is broken energy is no longer guaranteed to be conserved. In other words, energy is locally conserved. Absolutely. But across the universe? Not guaranteed. I've certainly seen solutions to the field equation in which energy is not conserved.

Dark energy is indeed a placeholder name (see my posts passim) and it is probably not a single 'thing'.

I don't think you're right to say it was the cause on the beginning of everything, there are no maths for that at all at the moment.

In addition the 'brake' on the inflation is more likely to have had some contribution from Dark matter assisting in a very minor way to the main reason for the cessation of expansion, namely the release of photons and the alignment/slowing down of the Cosmos to there being an imposed upper limit of all velocities, namely that of the speed of light.

At a quantum level energy is still a balanced account, nothing comes and nothing goes, the vast distance reduction is an effect of those two dark entities and that has been reasonably well understood since about 2011.