Search for a command to run...
Astronomers estimate that the number of comets orbiting the Sun is in the billions; the comets' orbits may change over time.
Like Uranus, Jupiter, and Mars, billions of comets orbit the Sun.
One example of a comet is 81P/Wild, whose orbit around the Sun once lay between Uranus's and Jupiter's orbits but is now positioned between those of Jupiter and Mars.
A comet's orbit around the Sun may change over time: the orbit of comet 81P/Wild once lay between the orbits of Uranus and Jupiter but is now positioned between those of Jupiter and Mars.