Why the 4th Gravitational Wave Is a “New Window on the Universe”

LIGO and Virgo reveal a gravitational wave was detected on two different continents. Here's what that means and why it matters.

A black hole devouring a neutron star. By Dana Berry/NASA.

The twin Laser Interferometer Gravitational-Wave Observatory (LIGO) is a collaborative effort. It’s basically a group of scientists who use specialized equipment to study gravitational waves. There are currently two such observatories in the US, one in Hanford, Washington and the other in Livingston, Louisiana. They use an interferometer, or a laser-based instrument, to detect even the minutest ripples in space-time as it relates to gravitational waves. The instrument is so delicate, it can pick up distortions one proton in width.  

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What Shape Is the Universe?

Our universe is flat, geometrically. But what exactly does "flat" mean?

This artist's impression shows how photons from the early universe are deflected by the gravitational lensing effect of massive cosmic structures as they travel across the universe. Image Credit: ESA

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