Figure 13.6 Charon in orbit around Pluto. Charon rotates on its axis in the same time as it takes to orbit Pluto. Charon therefore shows the same face towards Pluto and would remain fixed at the same point in the sky.
The average distance between Charon and Pluto is one-twentieth the distance between the Earth and our Moon. The combined masses of Pluto and Charon amount to less than one four-hundredth of Earth's mass.
The best pictures of Pluto and Charon have come from the Hubble Space Telescope. Both bodies are thought to consist of rock and ice. Charon's surface is probably covered with dirty water ice, which is why it doesn't reflect as much light as does Pluto. The Hubble observations show that Charon is bluer than Pluto.
Was this article helpful?