US scientists detect echoes of Big Bang

Mar 18, 2014, 10:35 IST | Agencies

A team of astrophysicists  claim they have detected so-called gravitational waves, which were the first tremors of Big Bang when time and space began about 13.8 billion years ago

Washington: Astronomers announced yesterday that they had discovered what many consider the Holy Grail of their field: ripples in the fabric of space-time that are echoes of the massive expansion of the universe that took place just after the Big Bang.

The beginning of the universe: An illustration explaining the Big Bang theory and the beginning of the universe. Pic/Thinkstock Images

Predicted by Albert Einstein nearly a century ago, the discovery of gravitational waves would be the final piece in one of the greatest achievements of the human intellect. It would help scientists understand how the universe began and evolved into the cornucopia of galaxies and stars, nebulae and vast stretches of nearly empty space that constitute the known universe.

“Detecting this signal is one of the most important goals in cosmology today,” John Kovac of the Harvard-Smithsonian Center for Astrophysics, who led the research, said in a statement.

The gravitational waves were detected by a telescope at the South Pole called BICEP2. The instrument, which scans the sky from the South Pole, examines what is called the cosmic microwave background, which is the extremely weak radiation that pervades the universe. Its discovery in 1964 by astronomers at Bell Labs in New Jersey, was hailed as the best evidence to date that the universe began in an immensely hot explosion.

The microwave background radiation, which has been bathing the universe since 3,80,000 years after the Big Bang, is a mere 3° above absolute zero, having cooled to near non-existence from the immeasurably hot plasma that was the universe in the first fractions of a second of its existence. The team not only found the pattern, but also discovered it was considerably stronger than expected.

Gravitational waves

Gravitational waves are ripples that carry energy across the universe. They were predicted to exist by Albert Einstein in 1916 as a consequence of his General Theory of Relativity. Particularly exciting are ‘primordial’ gravitational waves, which were generated in the first moments of the universe's birth. These carry vital information about how the universe began.

The science world reacts

This has been like looking for a needle in a haystack, but instead we found a crowbar.
— Clem Pryke, co-leader of the team, University of Minnesota

This work offers new insights into some of our most basic questions: Why do we exist? How did the universe begin? These results are not only a smoking gun for inflation, they also tell us when inflation took place and how powerful the process was.
— Avi Loeb, Harvard theorist

This is a totally new, independent piece of cosmological evidence that the inflationary picture fits together.
— Alan Guth, theoretical physicist

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