1.4 Keplers Laws and Cycles

Front

What shape do the orbits of planets take according to Kepler's First Law?

Back

Ellipses.

Front

What is the maximum eccentricity an ellipse can have?

Back

1.

Front

What does eccentricity measure in an orbit?

Back

A measurement of how elliptical an orbit is.

Front

What is the term for the closest point in a planet's orbit to the Sun?

Back

Perihelion.

Front

What is the term for the farthest point in a planet's orbit from the Sun?

Back

Aphelion.

Front

According to Kepler's Second Law, what happens to a planet's speed as it gets closer to the Sun?

Back

It moves faster.

Front

What is Kepler's Third Law?

Back

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

Front

What is the semi-major axis in an ellipse?

Back

The longest diameter of the ellipse.

Front

What is the focus of an ellipse?

Back

One of the two fixed points used to define an ellipse.

Front

How does the eccentricity of a circle compare to that of an ellipse?

Back

A circle has an eccentricity of 0, while an ellipse has an eccentricity between 0 and 1.