"This has been like looking for a needle in a haystack, but instead we found a crowbar," said co-leader Clem Pryke of the University of Minnesota.
In a major discovery for understanding the origins of the universe, US scientists said Monday they have detected echoes of the Big Bang 14 billion years ago.
The "first direct evidence of cosmic inflation," or the rapid growth spurt that came in the first moments of the life of the universe, was found with the help of a telescope at the South Pole, and was announced by experts at the Harvard-Smithsonian Center for Astrophysics.
The detection of these gravitational waves represents the last untested element of Albert Einstein's general theory of relativity, filling in a major gap in our understanding of how the universe was born.
The waves are ripples that move through space and time, and have been described as the "first tremors of the Big Bang." Their detection confirms an integral connection between quantum mechanics and general relativity.
"Detecting this signal is one of the most important goals in cosmology today. A lot of work by a lot of people has led up to this point," said John Kovac, leader of the BICEP2 collaboration at the Harvard-Smithsonian Center for Astrophysics.
The telescope targeted a specific area of sky known as the "Southern Hole" outside the galaxy where there is little dust or extra galactic material to interfere with what humans could see with the potent sky-peering tool.
By observing the cosmic microwave background, or a faint glow left over from the Big Bang, small fluctuations gave scientists new clues about the conditions in the early universe.
The gravitational waves rippled through the universe 380,000 years after the Big Bang, and these images were captured by the telescope.
"The South Pole is the closest you can get to space and still be on the ground," said Kovac.
"It's one of the driest and clearest locations on Earth, perfect for observing the faint microwaves from the Big Bang."
Rumors of the landmark discovery began to circulate Friday, as the hastily convened press conference was first announced.
However, scientists said they spent three years analyzing their data to rule out any errors.
Harvard theorist Avi Loeb said the findings provide "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," Loeb said.
According to theoretical physicist Alan Guth, who proposed the idea of inflation in 1980, described the latest study as "definitely worthy of a Nobel Prize."
"This is a totally new, independent piece of cosmological evidence that the inflationary picture fits together," Guth, of the Massachusetts Institute of Technology, was quoted as telling the journal Nature.
SOUTH POLE TELESCOPE
The gravitational waves were detected by a radio telescope called BICEP2 (Background Imaging of
Cosmic Extragalactic Polarization). The instrument, which scans the sky from the South Pole, examines what is called the cosmic microwave background, 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 380,000 years after the Big Bang, is a mere 3 degrees 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 background radiation is not precisely uniform. And like light, the relic radiation is polarized as the result of interacting with electrons and atoms in space.
Computer models predicted a particular curl pattern in the background radiation that would match what would be expected with the universe's inflation after the Big Bang.
"It's mind-boggling to go looking for something like this and actually find it," Clem Pryke, a physicist at the University of Minnesota and another lead scientist on the collaboration, told reporters.
"Theorists are forever sending the experimentalists on wild goose-chase missions. When we first saw hints of a signal we totally didn't believe it."
It will be up to other teams of scientists, working with an array of Earth-based, balloon-launched and space telescopes, to verify the findings.
"This is the smoking gun for inflation," Kamionkowski said. But even if the results hold up, "we've learned only that inflation has sent us a telegram, encoded on gravitational waves and transcribed on the cosmic microwave background sky."
It will be essential, he added, "to follow through with more detailed and precise measurements to infer fully what this telegram is telling us."
QUANTUM HINTS
The detection of gravitational waves may help physicists realize a dream of Einstein's that he died before achieving: unifying all the forces of nature.
Three of the four forces have been unified, which means that physicists have shown that they are facets of the same basic force. But the fourth, Einstein's beloved gravity, remains the odd man out: it seems to be a property of space rather than a consequence of subatomic, or quantum, particles as the other forces are.
The three quantum-based forces are electromagnetism, the weak nuclear force (responsible for radioactivity) and the strong nuclear force (which glues together the protons and neutrons in atomic nuclei).
Because cosmic inflation was powered by quantum effects, with the universe springing from a volume smaller than a subatomic particle, primordial gravitational waves were also created by quantum processes, cosmologists believe. If so, then by scrutinizing the gravitational waves that pervade today's cosmos, scientists might finally show that all four forces of nature arise from a single uber-force, achieving Einstein's dream.
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