Why That Gravitational Wave Discovery Is So Heavy

Feb 22, 2016

You have likely read or heard about the recent detection of gravitational waves from the Large Interferometer Gravitational Wave Observatory (LIGO). “Why is this such a big deal?” you might ask. “Aren’t astronomers making discoveries every day now?” Well, it is a big deal, with cosmic potential. Here’s why.

First of all, the ability to detect a black hole in itself is an exciting discovery. Black holes are fabulously difficult to detect precisely because they are black – meaning that no light, or matter can escape from them. They are pockets of space that have become so massive and dense that they have collapsed in on themselves. Black holes are some of the heaviest objects in the universe, but we can’t see them. The only thing that does escape from them, it seems, is gravity. So, we can detect them fairly easily if we can detect the gravity field that they are creating.

Until now, the only way to detect the gravity was to see if something else moved around and we couldn’t see what was causing it to move. It is a little like watching a master illusionist and spotting his tricks. This was the first time that scientists have been able to directly detect a black holes existence.

Secondly, there were two black holes that collided. This is suspected of being an extremely rare event in the universe. The collision that was detected actually happened over a billions years ago, many trillions of trillions of miles away.

The two objects that collided were unimaginably heavy. If you took the earth, Mars, Jupiter, Saturn, and all the planets and matter in our solar system and combined them with our sun and into one big ball, it would still only weigh a tiny fraction of just one of the black holes in the collision. Not only that, all that material, comprising over 40 million Earths, was compressed to the size of a pinhead. To Tiny pinhead sized objects trillions of miles away, and they were still able to hear it. Amazing!

Okay, so the event was amazing and the fact that we could detect it was amazing, but why should I care?

You should care because this marks the beginning of a new age. Until now, we have been able to LOOK up at the stars with visible light and extensions of the electromagnetic spectrum.

We have been able to see the events unfolding in the cosmos, but that is all, just see them. This means that we can only look out in a straight line. If there is a nebula, we can’t see what is on the other side. If there is a large star, the back side of it is hidden. We can only look out and see the grand play of our universe unfolding.

All the telescopes and detectors we have been using have followed the same technology, detecting electromagnetic waves as they arrive at our doorstep. Each detector has been tuned to a different frequency, allowing us to see all the colors of the universe and every time we used a new color, we saw something amazing and unexpected.

The LIGO operates at a totally different system. It is not looking for new colors it is not looking for any colors it is listening to the waves, the ripples in the fabric of space itself. If all the telescopes we have been using to watch the universe are our eyes, then the LIGO is our ears

Since Galileo first pointed his telescope at the stars, we have been watching the stars dance. We have watched galaxies form and collide, we visit the birth and death of stars. We have been watching this grand event and all of the instruments playing their piece in a beautiful orchestra of light and dazzling spectacle, And now, someone has just turned on the sound!

LIGO officials are excited about the possibility to peer into the heart of supernova, get a closer look at the inner working of a neutron star or learn more about the nature of the graviton particles themselves. This is because, like sound on Earth, LIGO is not limited to what appears unimpeded in a straight line. Just as you can hear noise around corners and through doors, LIGO can hear events in the universe that we can not see. If you think that watching at movie is fun, now we have the sound to go with it.

Kip Thorne of Caltec is excited about these potential discoveries, but he also sees LIGO’s contribution being much more pervasive. “When we look back on the era of the Renaissance, and we ask ourselves, ‘What did the humans of that era give to us that’s important to us today?’ I think we would all agree it’s great art, great architecture, great music,” he said.

“Similarly, when our descendants look back on this era, and they ask themselves, ‘What great things came to us?’ … I believe there will be an understanding of the fundamental laws of the universe and an understanding of what those laws do in the universe, and an exploration of the universe,” Thorne added. “LIGO is a big part of that. The rest of astronomy is a big part of that. And I think that cultural gift to our future generations is really much bigger than any kind of technological spin-off, than the ultimate development of technology of any kind. I think we should be proud of what we give to our descendants culturally.”