Discuss “Experiment of the week: Satellite used to study general relativity”

Gravity Probe B, a well-endowed NASA/Stanford satellite, is at this moment orbiting the Earth. The satellite’s main feature is its four perfectly spherical, shiny balls. These balls serve as the world’s most perfect gyroscopes, used in an extraordinarily complex and expensive experiment to observe the effects of general relativity.

After Einstein introduced the idea that the fabric of space-time is warped by mass, other scientists used his theory to predict unexpected phenomena. Many general relativity effects have been experimentally observed, such as Sir Arthur Eddington’s 1919 jungle expedition to observe starlight bent by the sun. Yet for many years, experimental confirmation of two additional and important general relativity phenomena...