Washington: Researchers have shed light on how ancient sound waves sculpted the cosmos, thus revealing the most accurate measurements ever made of the large-scale structure of the universe between five to seven billion years ago.
Physicists on the Baryon Oscillation Spectroscopic Survey (BOSS) attained this by observing the primordial sound waves that propagated through the cosmic medium about 30,000 years after the Big Bang, the Discovery News reported.
And until now, the data supports the theory that our universe as flat, constituting roughly a quarter cold dark matter, and four percent ordinary matter, with the rest made up of a mysterious force dubbed “dark energy.”
A hundred years ago scientists thought that the universe was steady and unchanging. Einstein invented the cosmological constant to expand the fabric of space-time after his own equations for general relativity wouldn''t allow for the cosmos to remain static as expected in a steady state universe.
Soon after, astronomer Edwin Hubble discovered that the universe was in fact expanding, consistent with Einstein’s original general relativity theory. Einstein then removed his cosmological constant describing his failure to predict an expanding universe in theory before it was proven by observation, as his biggest blunder.
In 1998, astronomers studying distant exploding stars called a Type 1A supernovae found that not only was the universe expanding, but that the rate of expansion was accelerating because of some type of unknown force or dark energy.
This bore a striking resemblance to Einstein’s cosmological constant. Either that, or our theory of gravity is incomplete. Answering this question is one of the foremost challenges in 21st century cosmology.
This new measurement from BOSS is important because that time frame - five to seven billion years ago - is the period when dark energy "turned on."
The BOSS findings will help physicists find out the exact nature of whatever is triggering our universe to accelerate in its expansion.
The discovery that led to the theory of dark energy depended on studying the red shifts of bright light from supernovae. BOSS, in contrast, looks at baryonic acoustic oscillation (BAO).
This phenomenon is the consequence of pressure waves (sound, or acoustic waves) propagating through the early universe in its earliest hot phase, when everything was just one big primordial soup.
Those sound waves created pockets where the density varied in regular intervals or periods, a “wiggle” pattern suggestive of oscillation, or vibration.
Then the universe cooled adequately for ordinary matter and light to go their separate ways, the former condensing into hydrogen atoms.
First Published: Wednesday, April 11, 2012, 12:26