9.6 Major Moons of Uranus, Neptune, and Pluto
9.6.1 Miranda of Uranus and Triton of Neptue
Read the below webpages to learn about Miranda and Triton—one of the major moons of Uranus and Neptune, respectively.
- Impey, Chris. “Uranus’ Miranda.” Teach Astronomy.
- Impey, Chris. “Neptune’s Triton.” Teach Astronomy.
9.6.2 Charon: Pluto’s Moon
To add to the mysteries of Pluto, we show in Figure 9.22 one of the best New Horizons images of Pluto’s large moon Charon. Charon is roughly half Pluto’s size (its diameter is about the size of Texas). Charon keeps the same side toward Pluto, just as our Moon keeps the same side toward Earth. What is unique about the Pluto-Charon system, however, is that Pluto also keeps its same face toward Charon. Like two dancers embracing, these two constantly face each other as they spin across the celestial dance floor. Astronomers call this a double tidal lock.
What New Horizons showed was another complex world. There are scattered craters in the lower part of the image, but much of the rest of the surface appears smooth. Crossing the center of the image is a belt of rough terrain, including what appear to be tectonic valleys, as if some forces had tried to split Charon apart. Topping off this strange image is a distinctly red polar cap, of unknown composition. Many features on Charon are not yet understood, including what appears to be a mountain in the midst of a low-elevation region.
Text Attributions
This text of this chapter is adapted from:
- Section 12.4 of OpenStax’s Astronomy 2e (2022) by Andrew Fraknoi, David Morrison, and Sidney Wolff. Licensed under CC BY 4.0. Access full book for free at this link.
