Overview:
- Astronomy: weighing the Earth
- Precision measurement: aLIGO
- Industrial Applications: MEMS gravimeters
Astronomy: weighing the Earth
- Nevil Maskelyne (Astronomer Royal) put in a “proposal” to the Royal Scoiety to weigh the Earth using the gravitational attraction of Schiehallion (Munro 1085m/3553ft)
- Maskelyne spent 17 weeks (July-September 1775) in a bothy measuring star positions
- The plan was to compare the attraction of the Earth and the mountain
- The deflection of the pendulum was measured relative to the stars Astronomy: weighing the Earth
- Maskelyne found that the mass of the Earth was 4.5 x 1024 kg
- The actual value is 5.98 x 1024 kg
- Not bad for the technology of that time
- However, it took him 17 weeks and bankrupted the Royal Society
- Charles Hutton (Mathematician / Surveyor) worked on calculating the mass of the mountain
- He split the mountain into chunks of similar height => contour lines
Precision measurement: aLIGO
General Relativity/Gravity Waves
- Gravitational waves are ripples in spacetime propagating at the speed of light (according to GR)
- Created by acceleration of massive compact objects
- In General Relativity gravity is described by the curvature of space-time
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View the entire Presentation:
Gravitational Physics: a Tour of Precision Measurement, Astronomy and Industrial Applications
Prof. Giles Hammond - Institute for Gravitational Physics, University of Glasgow