Front

What is Kepler's 1st Law of Planetary Motion?

Back

Planets move in elliptical orbits with the Sun at one focus.

Front

What is Kepler's 2nd Law of Planetary Motion?

Back

A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.

Front

What is Kepler's 3rd Law of Planetary Motion?

Back

The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.

Front

What does eccentricity measure in an orbit?

Back

Eccentricity measures the deviation of an orbit from being circular; it ranges from 0 (circle) to 1 (parabola).

Front

How does the eccentricity of Venus (0.007) compare to that of Mercury (0.206)?

Back

Mercury is more eccentric than Venus.

Front

What shape do planetary orbits take according to Kepler's laws?

Back

Planetary orbits are elliptical.

Front

What is the significance of the semi-major axis in Kepler's 3rd Law?

Back

The semi-major axis is the longest radius of an ellipse and is used to determine the orbital period of a planet.

Front

What happens to a planet's speed as it gets closer to the Sun?

Back

A planet moves faster in its orbit when it is closer to the Sun.

Front

What is the formula for Kepler's 3rd Law?

Back

T^2 ∝ a^3, where T is the orbital period and a is the semi-major axis.

Front

What does it mean for a planet to have an eccentricity close to 1?

Back

It indicates that the orbit is highly elongated and more like a parabola.