Astronomers discover echoes of Big Bang expansion

Astronomers announced Monday 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.

Researchers say this is evidence that a split-second after the Big Bang, the newly formed universe ballooned out at a pace so astonishing that it left behind ripples in the fabric of the cosmos. The ripples, called gravitational waves, were predicted by Albert Einstein nearly a century ago.

"This detection is cosmology's missing link," Marc Kamionkowski, a physicist at Johns Hopkins University and one of the researchers on the collaboration that made the discovery, told reporters on Monday at a press conference at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

If the finding is confirmed, it will be a major advance in the understanding of the early universe, experts said. Although many scientists already believed that an initial, extremely rapid expansion occurred, they have long sought the type of evidence cited in the new study.

The results reported Monday emerged after researchers peered into the faint light that remains from the the creation of the universe nearly 14 billion years ago.

Astronomers scanned about 2 percent of the sky for three years with a telescope at the South Pole, where the air is exceptionally dry and clear. They were looking for a specific pattern in light waves within the faint microwave glow left over from the Big Bang when they observed the gravity waves.

The existence of gravity waves must be confirmed by other observations — standard procedure for scientific discoveries — and if the finding holds up, it could serve as the missing evidence for two theories: Einstein's relativity and cosmic inflation.

The discovery "gives us a window on the universe at the very beginning," when it was far less than one-trillionth of a second old, said theoretical physicist Lawrence Krauss of Arizona State University, who was not involved in the work.

Right after the Big Bang, the universe was a hot soup of particles. It took about 380,000 years to cool enough for the particles to form atoms, then stars and galaxies. Billions of years later, planets formed from gas and dust orbiting stars. The universe has continued to spread out.

Einstein's theory of relativity, published in 1915, launched the modern era of research into the origins and evolution of the cosmos. The theory explains gravity as the deformation of space by massive bodies, like planets and stars.

The theory of cosmic inflation, developed in the 1980s, predicted gravitational waves. It also posited that in a split second after the Big Bang, the nascent cosmos expanded exponentially — inflating in size by 100 trillion times.

Einstein theorized that space is like a flimsy blanket, with embedded bodies causing it to curve rather than remain flat. The curvatures of space are not stationary, he said. Instead, the gravitational waves propagate like ripples in a lake or seismic waves in Earth’s crust.

Although the theory of cosmic inflation received a great deal of experimental support, the failure to find the gravitational waves it predicted caused many cosmologists to hold off their endorsement.

That may change after the announcement on Monday. "These results are not only a smoking gun for inflation, they also tell us when inflation took place and how powerful the process was," said Harvard University physicist Avi Loeb.

The strength of the signal from the gravitational waves is tied to how powerfully the universe expanded during the brief period of inflation.

Monday's findings were announced by a collaboration that included researchers from the Harvard-Smithsonian Center for Astrophysics, the University of Minnesota, Stanford University, the California Institute of Technology and NASA's Jet Propulsion Laboratory. The team plans to submit its conclusions to a scientific journal this week, said its leader, John Kovac of Harvard.

Al Jazeera and wire services