How Precision Instruments Beyond Imagination Detect Gravitational Waves

Jan 7 2017 -- 11:30 AM

The detection of gravitational waves, which happened for the first time in February of last year, marked another critical win for Einstein's theory of relativity, as well as the dawn of a new way of sensing the cosmos. But even though the detection may have been marked with lots of celebration--as well as plenty of top spots on 2016's lists of biggest scientific breakthroughs--relatively few people realized what actually went into the making of the Laser Interferometer Gravitational Wave Observatory (LIGO).

To shed some light on how extraordinary LIGO is as a scientific instrument, science educator and YouTuber Derek Muller (Veritasium), who's responsible for a bunch of stellar science videos including this one on pilot wave theory, visited with Caltech Professor of Physics, Rana Adhikari.

In the video, Adhikari, a leader on the LIGO project, walks Muller through what it was like for researchers to finally discover gravitational waves, and also clarifies how they were detected using a 1 megawatt laser that could "power a thousand homes" or "vaporize" your head. In some asides throughout the video, Muller highlights exactly how nuts LIGO is in terms of mind-bending specifications:

"So what was needed to detect gravitational waves? ... A megawatt of laser power to minimize shock noise of exactly one wavelength, because we're trying to measure just a trillionth of that wavelength continually inserted to replace older light that's been stretched and squished in the world's second largest vacuum chamber at just a trillionth of atmospheric pressure, hitting the smoothest mirrors ever created [which are] suspended by silica threads at two distant sites to eliminate noise, with four-kilometer-long arms to increase the magnitude of gravitational waves to just a thousandth of the width of a proton."

And while the detection of gravitational waves by LIGO is doubtlessly an achievement that took place on the edge of human understanding, Adhikari believes this is only the beginning. "I think the next logical step is to go from two signals to detecting all the black holes in the universe all the time," Adhikari says in the video. "We have to do a lot better than what we're doing now, but I see it... within our grasp."

What do you think about this "behind the scenes" look at LIGO? Let us know your thoughts in the comments below!

Image: Veritasium