1. H8: Evidence for general relativity

2. 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

3. Bending of light
Bending of light can have an affect of acting like a lens
We call this gravitational lensing

4. Gravitational lensing

5. Gravitational lensing

6. 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

7. 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

8. 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