General Science

What’s the Big Deal About Gravitational Waves?

posted: 10/16/17
by: Jason Ginsburg

NASA's Goddard Space Flight Center CI Lab

Scientists at LIGO (The Laser Interferometer Gravitational-Wave Observatory) in the US and Virgo in Europe have just made a big announcement: For the first time, they've directly detected gravitational waves and light from a huge collision of neutron stars. Astronomers were able to observe this spectacular event from virtually every time of energy and wavelength.

What does that mean? And why is it important? And what are gravitational waves, anyway? Science Channel breaks it down.

What happened?
130 million light-years away, two neutron stars that had been circling each other finally collided. The titanic explosion generated gamma rays, along with the types of radiation that are familiar to us -- X-ray, ultraviolet, visible light, infrared, and radio waves.

But the crash also created gravitational waves. And this time, astronomers had observatories ready to detect them. So this was the first opportunity to witness a cosmic event through all these different "lenses."

What are gravitational waves?
They're ripples in space-time; tiny alterations in the fabric of reality itself. Gravitational waves are "not another part of the electromagnetic spectrum; it is a whole new spectrum in itself. It's a completely different way of getting information from things," Cambridge University astrophysicist Anthony Lasenby told Wired.

Because they're not part of the electromagnetic spectrum, gravitational waves aren't scattered by cosmic dust, absorbed by objects, or distorted by distance. In fact, they can pass through matter effortlessly, which is why they're so hard to capture. That's where LIGO comes in.

A. Simonnet - NSF LIGO Sonoma State University

What is LIGO?
It's an observatory with locations in Washington State and Louisiana. There are no telescopes or radar dishes. LIGO consists of twin lasers beamed at mirrors 2.5 miles (4 km) away. Gravitational waves distort the laser beams ever so slightly, causing tiny disturbances, thousands of times smaller than the nucleus of an atom. That's how the waves are observed.

Why are gravitational waves important?
They offer another way of viewing the universe. Just as a nebula looks different when seen from different wavelengths, stellar phenomena look different, and provide different information, when seen with gravitational waves.

Take black holes, for example. We can't use light to observe them because they suck in all the light around them. But they generate enormous gravitational waves, which can be observed without being scattered or altered as they zoom through space.

France A. Cordova, director of the National Science Foundation, which funds LIGO, called the neutron-star collision "a rare event that transforms our understanding of the workings of the universe" that helps astrophysicists "expand our opportunities to detect new cosmic phenomena and piece together a fresh narrative of the physics of stars in their death throes."

Gravitational waves also allow us to see further back in time than light waves. They can teach us about Big Bang, cosmic inflation, and the nature of the universe itself.

Karan Jani - Georgia Tech

Is there any money in this?
Indeed there is! Astronomers detected heavy elements, including lead, gold, and platinum, generated by the collision. It may be that all precious metals in the universe are created by spectacular stellar deaths.

If the explosion was 130 million light-years away, then that means...
Yep. What's breaking news here on Earth actually happened while Triceratops were roaming the planet.

Anything else cool about this discovery?
You've heard of novas and supernovas. Get ready for a kilonova. It's the name for the collision of two neutron stars, or a neutron star and a black hole. Either event unleashes gigantic amounts of energy and gamma rays. The explosion is 1,000 times brighter than a nova...though only a fraction as bright as a supernova, despite its awesome name.

Learn more about gravitational waves tonight at at 6p on Science Channel.

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