What is a gravitational wave?

About LIGO

• 2 sites: Livingston, LA; Hanford Site, WA
• Sister project in Europe: VIRGO
• Cost: about a billion USD

LIGO at the Hanford Site

LIGO design

First direct detection: GW150914

LISA (and LISA pathfinder)

To look at longer wavelengths, need to go into space!

LISA mission profile

• LISA: three arms (six lasers), 2.5 M km separation
• Launch by 2034

Possible signals

Pulsar timing arrays

Pulsar timing arrays

• One the biggest single users of radio telescope time
• And the most demanding of solar system ephemerides!

Cosmic strings

Cosmic string loops

Cosmic string cusps

Higgs boson

How did the Higgs get that way?

Matter-antimatter asymmetry

The end of inflation