Tuesday, October 4, 2011

Research on dark energy wins physics Nobel Prize

Three scientists that have been working on a mysterious force in the universe called dark energy have won the Nobel Prize in physics. Saul Perlmutter, Brian Schmidt and Adam Riess have studied supernovae, which are basically exploding stars, to measure the expansion of the universe over time. While they anticipated to find that it would slow over time, they found that the expansion of the universe is actually accelerating. This stunning observation required the presence of a still largely unknown force, fittingly dubbed dark energy. It is thought that this mysterious energy causes an effect that opposes gravity. We know there has to be such a force, as the universe would otherwise crumble because of the gravity that is exerted by matter.

Dark energy is not to be confused with dark matter, which is equally mysterious, but not the same thing. While dark energy is the force responsible for the accelerating expansion of the universe, dark matter actually functions the same as normal matter, in the respect that it exerts a gravitational pull. We are unable to detect dark matter and dark energy, but we know it has to be there. As said, dark energy explains why gravity does not cause the universe to crumble, while the presence of dark matter is needed to explain the effect of gravity that can not be explained by visible matter: if planets and stars only had to rely on the gravity of visible matter, then they would fly away from each other, and galaxies that consists of many stars and planets could not exist.

While it is not known what dark energy and dark matter are made of, we know it must be created during the Big Bang, when the universe as we know it started expanding. In the coming decades, scientists will try to hunt down the particles that make up dark energy and dark matter. Meanwhile, it is already known that only 4 percent of the universe is made up of visible matter. The rest consists of dark energy (74 percent) and dark matter (21 percent).

The fact that almost everything in the universe consists of energy and matter we can not see, is intruiging. There are many more secrets waiting to be discovered, that could radically change our view on the massive space we find ourselves in.

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