Gravitational waves are ripples in the curvature of spacetime that are generated in certain gravitational interactions and propagate as waves outward from their source at the speed of light.

On October 16, 2017, many observatories simultaneously announced the first detection of gravitational waves.

One is that the U.S.-based Laser Interferometer Gravitational-Wave Observatory and the Europe-based Virgo detector have now both detected gravitational waves from the collision of two neutron stars; previously, they’d seen gravitational waves only from black hole collisions.

Check out these articles:

http://earthsky.org/space/ligo-virgo-gravitational-waves-neutron-stars-merger

https://www.youtube.com/channel/UCAY-SMFNfynqz1bdoaV8BeQ

http://earthsky.org/space/what-are-gravitational-waves