What is dark energy?

[controllah]

I just saw the last few minutes of Through the Wormhole show on dark energy. They kept saying, we have no idea what it is. I haven't been in science classes since high school (and even then I was stoned most of the time), and I've read only 2 books on science on my own: A Short History of Nearly Everything and A Briefer History of Time. But the way Einstien's theory of gravity is explained is the warping of space. Kind of like if you put a bowling ball in the middle of a trampoline it will warp it and attract other smaller objects on the trampoline to it. My question is couldn't dark energy be what's under the trampoline? If one pushes up on the trampoline, then it would make objects on the trampoline move farther apart? Thanks for answering my question here and promoting my laziness in reading the material on my own.

[Jack]

I'll mention my understanding of it in an oversimplified manner.

Cosmologists expected the galaxies to be slowing down after the expansion of the Big Bang. Instead the evidence shows that not only are the galaxies still moving away from one another at high speed, they are actually moving faster as time passes. The only way they could account for this was to postulate a form of matter pushing the galaxies apart that isn't yet detectable. They call it dark matter for want of a more accurate and descriptive name. Since energy and matter are different forms of the same thing, there's also dark energy, about which I know even less.

(Disclaimer: I'm not a cosmologist nor have I ever played one on TV)

[controllah]

Thanks, thats pretty much what I got out of the 2 books and the last 15 minutes of the show. I'm wondering if this moving apart could be the effects of the same forces of gravity we know of, but in a parallel universe. As in, matter in our universe warps space in a certain way. And matter in another universe would warp OUR space in the oppsoite fashion. This is why we cant really detect it. Does this remotely make sense? I guess this is my question.

[Charlatan]

The universe is alsways growin outwards. This is where dark matter on the outskirts becomes space. I suspect that the dark matter is actually being exposed to 'stabalizer' atoms or whatever.

Dark energy is latent energy that affects all matter, but probably won't until it is exposed to new things that define it.

[marharth]

I don't think dark matter or dark energy exists, I think its part of a sub atomic force we haven't found out yet.

[Senor Hoint]

When you do the calculations the universe's expansion should be slowing down and approaching the point where it starts to contract, because of gravity. But instead we observed the opposite--the expansion of the universe is accelerating. This observational fact necessitated the postulation of "dark energy," which is currently only a theoretical construct which explains this acceleration of expansion.

[controllah]

Yep, nm, i did googling. I found where someone else already thought what i was thinking and explained it much better.

[marharth]

When you do the calculations the universe's expansion should be slowing down and approaching the point where it starts to contract, because of gravity. But instead we observed the opposite--the expansion of the universe is accelerating. This observational fact necessitated the postulation of "dark energy," which is currently only a theoretical construct which explains this acceleration of expansion.

Partly correct, the universe is expanding out fast and with our current laws of physics that does not make sense.

So with our current set of physics, we need dark energy or something else that is undetectable yet helping the expansion. It doesn't have to be a new type of matter or a new type of energy though, it may be something we already have observed but do not fully know how it works even if we think we might know.

However it is also possible that our set of laws of phyics are not entirely correct, and we may need to drastically change them.

Around the time of 2012-2020, the LHC may or may not find the Higgs boson particle.

My timeline is quite large, and not exact of course. That includes the research and the examination of data.

I beleive the Higgs boson will not be found ever, and that would lead to other research to try to prove the standard model.

I personally think a lot of theoretical physics are wrong, and I do not agree with the standard model.

[Yarn]

Jack:

Cosmologists expected the galaxies to be slowing down after the expansion of the Big Bang. Instead the evidence shows that not only are the galaxies still moving away from one another at high speed, they are actually moving faster as time passes. The only way they could account for this was to postulate a form of matter pushing the galaxies apart that isn't yet detectable. They call it dark matter for want of a more accurate and descriptive name. Since energy and matter are different forms of the same thing, there's also dark energy, about which I know even less.

Dark matter isn't pushing galaxies apart, that's dark energy. Theoretically, dark energy is infinite because it has an unchanging constant concentration throughout all of space. Therefore, as space expands the total amount of dark energy in the universe increases. Because dark energy in turn propels the expansion of space, the universe is expanding at an accelerating rate as the total amount of space it takes up increases. This has overwhelmed the aggregate force of gravity so that the universe is headed towards an infinite diffuse death.

In contrast, dark matter is of a constant quantity. It forms halos around galaxies, thereby manifesting its existence through gravitational effects on stellar distribution. It also reduces the rate galaxies move apart.

My own pet theory, which is probably not original, is that dark matter is like ordinary matter minus the electrons and any other source of charge. Without electrons, all you have left is a nucleus. A nucleus makes up only a very very small portion of an atoms volume, so without the electrons, the radius over which the particles interact is made infinitesmal relative to what it is for atoms. Plus, without electrons there is nothing to cause adjoining particles to aggolmerate into complexes consisting of more than one nucleus through the attraction of opposite charges, the formation of covalent bombs, and van der waals forces.

Stellar masses, such as nebula, condense through an accretion disk. They fall towards a center of gravity, but they do so at an angle. So they miss the said center; then they orbit it. As molecules hit eachother, they exert friction on one another and stick together through the aforementioned bonding forces. Thereby they combine and fall towards the center of gravity as their orbits shrink through the slowing down caused by the friction. Eventually they meet up at the center forming huge objects, such as planets, stars, and blackholes. Without electrons, you lack the bonds, and you lack the friction. Ergo, there is no accretion, and the mass just orbits a center of gravity (such as the supermassive black hole at the center of every galaxy) forever*.

*-Or at least until and unless the stars all get eaten by black holes and the black holes evaporate away (scientists haven't yet reached a concensus on whether black holes evaporate).

Returning to dark energy, it is the only possible source that could fuel a perpetual energy machine. This energy could, if concentrated, then be converted into matter. If the machine that did this, which would have to be lightyears in size, could create matter fast enough to replace the matter chipped off of it by random quantum effects, it could save the universe from completely dying by producing islands of indefinite concentrated matter and energy. But that is a big if.

The universe is approaching the point where the farthest points within the universe have so much spatial expansion occuring between them they are going to be moving away from each faster than the speed of light. The speed of light limits the rate at which things can move through space but not the rate at which space can expand.

Controllah:

If one pushes up on the trampoline, then it would make objects on the trampoline move farther apart? Thanks for answering my question here and promoting my laziness in reading the material on my own.

That would require negative gravity, something for whose existence we have no evidence. Its presence would be a requirement for a stable wormhole, though it may not be possible to travel out of any wormhole meaning a wormhole would be a deadend.

[Angry Citizen]

But instead we observed the opposite--the expansion of the universe is accelerating.

One begins to wonder if the rate of acceleration is in fact a constant, or whether it could be slowing down.

[Senor Hoint]

One begins to wonder if the rate of acceleration is in fact a constant, or whether it could be slowing down.

Good question. I bet we could find out the answer with access to the observations. Nothing I've ever read has said anything on that question, though.

[Yarn]

Space expands at a constant rate per given amount of space, meaning as space expands it does so at an accelerating rate. Within this model, I would suppose the rate of acceleration will increase indefinitely because the more space there is the greater rate at which mich more space is made.