Kepler's First Law

Front

What is Kepler's First Law?

Back

Kepler's First Law states that planets move in elliptical orbits with the Sun at one of the two foci.

Front

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

Back

Elliptical.

Front

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

Back

Perihelion.

Front

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

Back

Aphelion.

Front

What are the two focal points in an elliptical orbit?

Back

The two focal points are points in space where the sum of the distances from any point on the ellipse to the two foci is constant.

Front

How does the eccentricity of an orbit relate to its shape?

Back

Eccentricity measures how much an orbit deviates from being circular; a value of 0 is a perfect circle, while values closer to 1 indicate more elongated ellipses.

Front

Which planet has the highest eccentricity in the solar system?

Back

Mercury.

Front

Do all planets in the solar system orbit the Sun in the same direction?

Back

Yes, all planets orbit the Sun in the same direction, counterclockwise when viewed from above the Sun's north pole.

Front

What is the focal length in an ellipse?

Back

The focal length is the distance between the two foci of the ellipse.

Front

What is the significance of the second focal point in a planet's orbit?

Back

The second focal point is a mathematically determined point in empty space that helps define the shape of the orbit.