Archive for February 2016

Einstein predicted their existence over a century ago, and physicists have been on the hunt for gravitational waves ever since. It’s just been made official that they found then, too.

According to researchers at the Laser Interferometer Gravitational Wave Observatory or LIGO, a month or so of round-the-clock testing has confirmed that a gravitational wave was sensed.

g wavesThe posible wave was observed on September 14th, 2015, around 5:51 am ET by both of the LIGO detectors, who were located in Livingston, Louisiana and Hanford, Washington at the time. The source of the findings was a supermassive hole collision that took place about 1.3 billion ears ago and, when it happened, converted three times the mass of the sun into energy in a fraction of a second.

The discovery’s publication was accepted by Physical Review Letters.

So what is a gravitational wave? They’re ripples in the universe caused by extremely energetic cosmic events that can range from exploding stars to supermassive black hole mergers. As they propagate through space and time, these waves can cause tiny tremors in atoms that make up matter.

Einstein predicted their existence in his theory of general relativity in 1916 and their existence was indirectly proven in the 1980’s, but this is the first time that the hunt for spacetime ripples actually came up with a real life occurrence.

The LIGO detector was created for this very purpose in 2002, but it took ten years to make the instrument sensitive enough to sense the minuscule gravitational waves and atomic jitters that would hit our world after two black holes collide in a distant galaxy. LIGO uses high powered lasers to measure tiny changes in distance between these two objects, but possible signals can be made from all kinds of outside factors like a train lumbering by, an earthquake, or a storm.

LIGO underwent a series of upgrades and has been functioning as its current version since 2015. Its powerful lasers and improved isolation system made its prospects of detecting the first gravitational waves better than ever before. A few scientists seen predicted that we’d have our first positive detection in 2016, though few saw reason to believe them.

LIGO apparently saw gravitational waves almost immediately after its most recent version came on. The hold up has been waiting for the team of scientists associated with the project to exhaustively investigate potential instrumental disturbances to confirm that the signal was indeed real.

greevityAccording to those scientists, the two black holes that collided were 29x and 36x times the mass of the sun, respectively. During the most powerful moments of their collision, LIGO estimates that their power output was about 50 times that of the entire visible universe.

“The description of this observation is beautifully described in the Einstein theory of general relativity formulated 100 years ago and comprises the first test of the theory in strong gravitation,” commented Rainer Weiss, the first proposer of LIGO. “It would have been wonderful to watch Einstein’s face had we been able to tell him.”

The discovery is said to open a new chapter in our exploration of space and time, especially since gravitational waves can now be used to probe mysterious celestial objects that do not emit light.

“There’s a lot of rich information encoded in gravitational waves,” said MIT astrophysicist Scott Hughes. “As an astronomer, I try to think about how to go from the ‘sound’ of the waveform that LIGO measures, to the parameters that produce that waveform.”