Indirect Evidence of Gravitational Waves

Arecibo Observatory.
Image courtesy of NAIC

The first evidence for gravitational waves came from two stars spiraling toward each other, found in 1974 by astronomers working at the Arecibo Observatory. Researchers watched the stars for many years and noticed that the time it took for the stars to orbit each other was decreasing over time.

Scientists Joseph Taylor and Russell Hulse suspected that the change in orbital periods was because the stars were losing energy as gravitational waves. They showed mathematically that if this were true, the orbital periods of the two stars should change by exactly the amount astronomers observed. In 1993, Taylor and Hulse won the Nobel Prize in Physics for this work.

Hulse and Taylor conducted their Nobel Prize work on radio signals detected by the largest radio telescope in the world. The telescope is located at Arecibo Observatory in Puerto Rico.


At the time of the discovery Russell Hulse (right) was a graduate student and Joseph Taylor (left) was his supervisor at the University of Massachusetts, Amherst.
Above images scanned at the American Institute of Physics, AIP Emilio Segre Visual Archives left: Physics Today Collection right: W. F. Meggers Gallery of Nobel Laureates