Shop Windows to the Universe

Arches National Park Geology Tour provides an extensive, visually rich description of the geology of Arches, by Deborah Ragland, Ph.D. See our DVD collection.
This is an image of Pluto with its moon Charon.
Click on image for full size
Image courtesy of NASA/JPL. This image is in the public domain.

Pluto & Charon, a double planet

Of all the planets and moons in the solar system, Pluto and Charon are the two which resemble each other the most closely. They are almost the same size, and they are very close together. They are so close together that they orbit the center of mass between them, and the center of mass goes around the sun. Pluto and Charon are so close that they may even share an atmosphere. Molecules may be drawn off Pluto and turn to solids on the surface of Charon.

The only other planet and moon in the solar system which could be a double planet are the Earth and the Moon. As in the case of the Earth and the Moon, the origin of such a system is hard to explain. The explanation which seems best is that some large object struck Pluto (and the Earth) and tore out a blob which became Charon (and the Moon) from the crust of the planet. In the case of the Moon, the Moon seems to be made of material very much like the Earth's crust and not like the Earth's more metallic interior. Likewise Charon may be made of more icy material which resembles Pluto's surface, rather than the more rocky interior of Pluto.


Shop Windows to the Universe Science Store!

Our online store includes fun classroom activities for you and your students. Issues of NESTA's quarterly journal, The Earth Scientist are also full of classroom activities on different topics in Earth and space science!

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

A Look at Pluto's Atmosphere

It may seem hard to believe that Pluto could have an atmosphere because it is so cold at 39 AU, where Pluto is found, but it does. Because there are times when Pluto is closer to the sun than is Neptune...more

The Moons of Pluto

Pluto has // Call the moon count function defined in the document head print_moon_count('pluto'); moons. One of the moons is very large. The large moon is named Charon. The other two moons are fairly small....more

Charon - Pluto's biggest moon

Charon is a moon of Pluto. Pluto has // Call the moon count function defined in the document head print_moon_count('pluto'); moons. Charon is much larger than Pluto's other moons. James Christy discovered...more

Pluto & Charon, a double planet

Of all the planets and moons in the solar system, Pluto and Charon are the two which resemble each other the most closely. They are almost the same size, and they are very close together. They are so...more

Questions to answer about Pluto

Pluto is so far away, and has never been explored. Questions to answer about Pluto include the following: What are the geologic features of the surface. (pictures of the surface) If there are bare spots,...more

A Look at Pluto's possible Magnetosphere

No one knows whether or not Pluto has a magnetosphere. Scientists were very surprised to find that Jupiter's icy moon Ganymede had a magnetosphere because it is hard to explain how an icy body can develop...more

Pluto

Pluto is a frigid ball of ice and rock that orbits far from the Sun on the frozen fringes of our Solar System. Considered a planet, though a rather odd one, from its discovery in 1930 until 2006, it was...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA