Center of mass -- extra solar planets
action = -reaction means when the earth is pulling on the moon, vice versa.
- Therefore the earth is also in orbit
- The earth and moon orbit their common center of mass
- the center of mass is where objects would balance on a teeter-totter
- demo -- large mass = earth, small mass = moon
- orbit. center of mass stays fixed between them
- both objects are on circular orbits
- the earth a small circle
- the moon a large circle
- for Jupiter and the sun, the center of mass is 0.96 x 10-3 times the distance from Jupiter to the sun.
- position just below the solar photosphere
- Sun’s orbit betrays the presence of Jupiter.
- periodic wobbles in space
- doppler shift of light