The Accelerating universe

Before astronomers found out that the universe was accelerating they belived that it was decelerating .The only question was if the decelerating would halt that expansion or not.But in 1997 two teams of astronomers who were observing completely changed that view.

The astronomers were observing supernovae explosions in the distant universe. These bursts of light shine briefly, with the intensity of a billion Suns and as a resault they become becons that astronomers can use to study the universe on its largest  scales. This is because, as the light  of the explosion travels through space, it suffers a redshift because of the expansion of the universe. When both teams did the calculations using data from different supernovae,they found out  that the figuers did not add up; the supernovae were fainter than expected. This could only be explained  if the expansion of the universe has accelerated, the only way to explain that the universe is accelerating is if it contains an exotic form on energy, known as vacuum energy. Matter, which produces gravity,can only cause  attraction so can the Universe. But vacuum energy, has the opposite effect.

~ by darkpanther14 on May 29, 2009.