H8: Evidence for general relativity
Bending of light General Relativity predicts that a light ray passing near the Sun should be deflected by the curved space-time created by the Sun’s mass The prediction was confirmed by astronomers during a total solar eclipse, by Eddington in 1919
Bending of light Bending of light can have an affect of acting like a lens We call this gravitational lensing
Gravitational lensing
Gravitational lensing
Gravitational red-shift When a source moves and it emits a wave, the wavelength will change If the source is moving away from us then the wavelength will be longer, this is called red-shift If the source is moving towards us then the wavelength will be shorter, this is call blue-shift
Gravitational red-shift This is often used to calculate the speed of distant star is Astronomy The faster the source is moving the greater the wavelength change It has been found that all sources are moving away from us (red-shift) Therefore the Universe is expanding
Pound-Rebka experiment Two scientists fired an EM wave through a 22 m tower In theory the wavelength will change as it is in the Earth’s gravitational field It showed the wavelength had shifted Therefore confirming Doppler effect due to general relativity