4.3 orbits

Question 1

What is Kepler’s first law?

Answer 1

Each planet moves in an elliptical orbit with the sun at one focus

Question 2

What is Kepler’s second law?

Answer 2

The line joining a planet to the centre of the sun sweeps out equal areas in equal times

Question 3

What is Kepler’s third law?

Answer 3

T^2 is proportional to r^3

Question 4

What is the radial velocity

Answer 4

Velocity of a star to/away from Earth