Lab 5 - Orbits and Kepler's Laws
A planet is discovered orbiting the star 51 Peg with a period of four days (0.01 years). 51 Peg has the same mass as the Sun. Mercury's orbital period is 0.24 years, and Venus's is 0.62 years. The average orbital radius of this planet is
less than mercury's
The Moon takes roughly 28 days to complete one orbit around Earth. If the orbital radius of the Moon were twice its actual value, its orbital period would be
more than 56 days
Two planets are observed going around a star. Planet Xoron has an orbital period that is twice as long as planet Krypton. Which planet has a shorter average orbital radius?
planet krypton
As a comet orbits around the Sun, its maximum speed is twice its minimum speed. What can we say about its orbit?
The comet is twice as far from the Sun at aphelion as at perihelion.
Why do the planets orbit the Sun (i.e. why don't they crash into the Sun)?
Although the planets experience a force of gravity from the Sun, since they are moving, their trajectories bend around the Sun rather than lead directly into the Sun.
If an astronomer claims to have discovered an object with a very eccentric orbit, which of the following best describes the orbital trajectory of the object?
It looks like a very squashed oval.
Suppose two comets, comet A and comet B, were orbiting the Sun, having the same average orbital radii. If comet A had a higher eccentricity than comet B, which comet would, during some portion of its orbit, have the highest orbital speed?
comet A
If Earth's orbit were very eccentric, but the average distance from the Sun were still 1 AU, its orbital period
would still be one year
