Focusing on Dark Energy With A Cosmic Lens

[n2doc]

By Lisa Grossman August 19, 2010



Our view of dark energy, the mysterious force that is shoving the universe apart, just got a little clearer. By observing the way large clumps of mass distort their local space-time into enormous cosmological lenses, astronomers have zoomed in on a quantity that describes how dark energy works.

“We have established the potency of a brand new technique to address this very fundamental problem,” said astrophysicist Priyamvada Natarajan of Yale University, coauthor of a paper in the August 20 Science describing the new results. Combined with earlier experiments, the new results lead to significantly more accurate measurements of dark energy’s properties, and could ultimately help explain what the bizarre stuff really is.

Dark energy was first proposed in 1998 to explain why the universe is expanding at an ever-increasing rate. Astronomers suggested that some kind of force, dubbed “dark energy” because of the shroud of mystery it hides in, that works against gravity to push matter apart.

Although earlier experiments convinced astronomers the enigmatic stuff exists, not much else is known about it. Dark energy makes up the majority of the mass and energy in the universe, about 72 percent. Another 24 percent is thought to be dark matter, which is easier to study than dark energy because of its gravitational tugs on normal matter. The regular matter that makes up everything we can see, including atoms, stars, planets and people, comprises just 4 percent of the universe.



Read More http://www.wired.com/wiredscience/2010/08/lensing-dark-energy/

[derby378]

1. Is there a consensus on whether or not neutrinos are dark matter?

I've heard the subject's been bounced around, but don't know what the general feeling is on where to put these guys.

[dimbear]

3. AFAIK they are not

They have a small but discernible mass.

That makes them ordinary matter.

[dipsydoodle]

2. Fate of Universe revealed by galactic lens

A "galactic lens" has revealed that the Universe will probably expand forever.

Astronomers used the way that light from distant stars was distorted by a huge galactic cluster known as Abell 1689 to work out the amount of dark energy in the cosmos.

Dark energy is a mysterious force that speeds up the expansion of the Universe.

Understanding the distribution of this force revealed that the likely fate of the Universe was to keep on expanding.

http://www.bbc.co.uk/news/science-environment-11030889