What is dark energy?

[bixaorellana]

"Dark energy is the name given to an unexplained force that is drawing galaxies away from each other, against the pull of gravity, at an accelerated pace.

Dark energy is a bit like anti-gravity. Where gravity pulls things together at the more local level, dark energy tugs them apart on the grander scale."

Read the full, fascinating article: www.space.com/scienceastronomy/090427-mm-dark-energy.html

[onlymark]

I do wonder if Darth Vader would find this dark energy useful?

[bixaorellana]

That is an interesting article, particularly in the sense of showing how what is "known" about the universe so far may be not only inadequate, but wrong.

[onlymark]

I tend to think we actually know very very little about the universe. It is such a vast thing that we have only found the surface, never mind scratched it.
Laws of physics that have been discovered and seem to fit, but when you get down to the quantum level, a lot don't seem to at all.

Laws that are deemed 'Universal' laws are apparently so because they 'fit' that small part that we have observed. To me it is a bit like looking around from the deck of a ship, a ship that everyone has always lived on since it formed in a big bang, observing water as far as you can see, formulating a law that says any structure must be hollow and displace it's own volume of water. Then saying that any structure you will ever see must be the same, as you don't know of the existence of land.

You can't have a Universal Law until you've gone round all the universe to see if it's the same. No matter how much you postulate and theorise, you cannot be sure.
And as scientists are finding out, there are more particles, more matter, more energies and there will always be more weeds in your garden than you ever thought possible and that you can shake a stick at.

[spindrift]

Here's the latest report on Dark Matter straight from the newsdesk of the Daily Mail.

www.dailymail.co.uk/sciencetech/article-1256666/Dark-matter-Large-Hadron-Collider-reveal-95-universe.html

[imec]

Dark Energy... you mean like Black Power?

[bixaorellana]

Sorry, Spindrift -- I'm just now seeing your news link. I have always found it fascinating -- if ungraspable by my mind -- how the big unknowns can be postulated and then sought.

[onlymark]

It may not exist -

www.dailymail.co.uk/sciencetech/article-1286668/Dark-energy-matter-exist-claim-scientists.html

[bixaorellana]

Interesting! And here is more about Tom Shanks, the professor referred to in #7's link:

One of the prime ways researchers tally how much these components contribute to the overall makeup of the universe is by measuring a dim glow of light pervading space that is thought to be left over from the Big Bang. The most detailed measurements yet taken of this radiation, which is called the cosmic microwave background (CMB), come from a spacecraft dubbed the Wilkinson Microwave Anisotropy Probe (WMAP)....
"It's such an important thing — the microwave background," said astrophysicist Tom Shanks of Durham University in England. "All the results in dark energy and dark matter in cosmology hang on it, and that's why I'm interested in checking the results."
...
Instead of using Jupiter as a calibration source, the way the WMAP team did, Shanks and Sawangwit used distant astronomical objects in the WMAP data itself that were emitting radio light.
"When we checked radio sources in the WMAP background, we found more smoothing than the WMAP team expected," [Shanks said]

Click on the blue text above to read the full article.

And of course, we have to remember that the Big Bang is itself a theory.