Scientists with the LIGO collaboration claim they have once again detected gravitational waves - the ripples in space-time produced by objects moving throughout the Universe. It’s the second time these researchers have picked up gravitational wave signals, after becoming the first team in history to do so earlier this year. This second detection boosts the likelihood that LIGO is truly measuring waves and not something else.
This simulation of the binary black-hole coalescence GW151226 shows two black holes of 14 and 8 solar masses orbiting each other. When it was announced that LIGO detected gravitational waves this past February, astrophysicists wondered about something else: Had the experiment found the “dark matter” that makes up most of the mass of the universe? The eight scientists from the Johns Hopkins Henry A. Rowland Department of Physics and Astronomy had already started making calculations when the discovery by the Laser Interferometer Gravitational-Wave Observatory (LIGO) was announced in February. Their results, published recently in Physical Review Letters, unfold as a hypothesis suggesting a solution
Yesterday, the LIGO collaboration announced the detection of a pair of merging black holes, a 14 solar mass black hole inspiraling and coalescing with an 8 solar mass black hole, only the second gravitational wave event ever seen. While some controversial evidence existed that the first black hole-black hole merger produced a gamma-ray burst, those results were hotly disputed, with advocates on both sides eagerly awaiting the results from the second merger. With the announcement yesterday, it became official: neither gamma-rays nor X-rays were seen, tipping the scales towards the long-awaited conclusion, merging black holes do not produce bursts of radiation. Before gravitational waves were
While LIGO can detect that an event happened, it can’t point out exactly where the source is, David Reitze, LIGO’s executive director, said at a news briefing at the astronomy meeting.
“An interferometer turns out to be a pretty poor telescope in the sense that it can’t actually localize events,” Reitze said. “It’s more like a microphone.”
The more detectors there are to catch the same event, the more they can narrow in on its location. Luckily, more seem to be on the way: Virgo should conduct its first run in early 2017, Japan is building the KAGRA detector, and there are tentative plans to build one in India, too.
