Scientists detect gravitational waves for the second time

Scientists with the The Laser Interferometer Gravitational-Wave Observatory (LIGO) collaboration say they have once again detected gravitational waves, or the ripples in space-time produced by objects moving throughout the universe.

This is the second time researchers have picked up gravitational wave signals, after becoming the first team in history to do so earlier this year.

According to commentators the second detection boosted the likelihood that LIGO was indeed measuring waves and not something else. "Seeing a second loud signal like this means the first detection wasn't just luck," AP reported quoting Duncan Brown, a LIGO researcher and a professor of physics at Syracuse University.

The two wave signals also occurred within just a few months of each other, suggesting that the detections might take place frequently.

As with the original finding, the waves originated from the merger of two black holes - super dense objects that formed when a star collapsed and died.

During the merger, the black holes rapidly spun around each other several times a second, before they joined together into a single extra-dense object.

The process led to the generation of massive gravitational waves that rippled outward at the speed of light. The waves travelled through space for 1.4 billion years before finally reaching earth on 26 December (or 25 December for those in the US), when they were picked up by LIGO's two observatories.

"This is what we call gravity's music," Louisiana State University physicist Gabriela Gonzalez, scientific spokeswoman for the discovery team said at a press conference yesterday, where the sounds from the two gravitational waves were played.

"These events - especially the first one - are the most powerful ones we have detected since the Big Bang," AP quoted Barnard College physicist Janna Levin, author of Black Hole Blues And Other Songs From Outer Space.