gravitational-waves

LIGO's first gravitational-wave detection confirmed a century-old prediction of general relativity and opened a new way to observe the universe.

Black holes come in sizes that span 10 orders of magnitude, from a few solar masses to tens of billions — but the range between roughly 65 and a few hundred solar masses appears nearly empty. A 2020 gravitational wave event punched straight through that forbidden zone, and nobody fully agrees on how.

On September 14, 2015, LIGO detected a ripple in spacetime from two merging black holes a billion light-years away. Here is how the instrument works and what it measured.

Neutron-star interiors remain uncertain. X-ray observations and mergers let researchers test dense-matter models and investigate heavy-element production.

LIGO's gravitational wave detectors produce a constant roar of noise. Machine learning is the ear that hears the cosmos whispering beneath it.

How LIGO detected gravitational waves from colliding black holes, confirming Einstein's prediction

A network of millisecond pulsars scattered across the Milky Way works as a galaxy-sized gravitational wave detector. In 2023, several independent collaborations reported the first evidence of a nanohertz gravitational wave background. Here is how pulsar timing arrays work and what they are finding.

Neutron stars pack more mass than the Sun into a sphere about the size of a city. This guide covers how they form, what lies inside them, how heavy they can get, and why pulsars, magnetars and neutron star mergers matter to physics.

Einstein predicted them in 1916. We detected them for the first time in 2015. Gravitational waves let us "hear" cosmic events that produce no light. Here's how they work and what they reveal.