Nathan Orr
Spring 2012
Image of Charon rendered by Celestia,a 3D astronomy program


Charon, also known as Pluto I, is the largest moon that orbits the recently classified dwarf planet Pluto, and is a little larger than half of Pluto's size. Discovered in 1978 by astronomer James Christy. Charon is named after the Greek mythological figure Charon who ferry's the souls of the dead across the river Acheron in to Hades. The leading theory in how Charon came to be Pluto's moon is the impact theory that the moon was part of Pluto and was broken off by a large impact. Charon has never been visited by any spacecraft, but is scheduled to be visited by the New Horizons mission in 2015. Charon has a diameter of 1207 kilometers and the mass of 1.52x1021 kilograms. Charon does not appear to have an atmosphere, and its surface seems to be covered with ice.


1. Universe Today - Charon Moon

Artist depiction of Charon from the surface of Pluto

Last Updated: February 26, 2010

Date Reviewed: 5/21/2012

Reviewed by: Nathan Orr

Accuracy: The information on this site is very similar to other sources like the sites listed below. There is a margin of error between all sources when it comes to diameter and mass since Charon has never been visited and its size must be calculated from Earth.

Readability and Clarity: Very easy to read, formatted in the style of a web article. The language is easy to understand, with the most complex vocabulary involving measurements such as kilometers.

Ease of Navigation: The page is formatted as an article and is easy to navigate, all you have to do is scroll down and keep reading. The bottom of the page has links to other pages on Universe Today regarding Pluto and Charon if more information is desired.

2. Solar Views - Charon

Photometric pictures of Charon

Last Updated: 2009

Date Reviewed: 5/21/2012

Reviewed by: Nathan Orr

Accuracy: Information is very close to that of the other Charon sources on this page.

Readability and Clarity: The page is very easy to understand, with any unusual vocabulary being defined immediately after the word. There is also a very useful table of statistics such as measurements and distances about Charon.

Ease of Navigation: The page is simply navigated, information is given in a list starting with historical information, going on to explain the moon's composition and so forth. All the reader has to do is scroll down.

3. Bright Hub - Facts about Pluto's moon Charon

The shining object in the center is Pluto, beneath it, directly to the right is Charon

Last Updated: June 1, 2010

Date Reviewed: 5/21/2012

Reviewed by: Nathan Orr

Accuracy: The site makes some generalizations such as "Charon... has characterizations that cannot be found anywhere else" but the basic facts and information on its discovery are accurate.

Readability and Clarity: The page is organized in a easy to read manner, listing numerical facts and then giving background information, each different piece of information is separated with a bold heading.

Ease of Navigation: Navigating the page is simple, merely read underneath a heading to get the required information.

4. Solar System Exploration - Charon: Overview

Photo showing how Charon was discovered, not how the black blotch (Pluto) has a growth in the first picture. That is Charon aside the moon

Last Updated: April 9, 2012

Date Reviewed: 5/21/2012

Reviewed by: Nathan Orr

Accuracy: Accurate information on the discovery of Charon in 1978.

Readability and Clarity: The page defines uncommon definitions, high school level reading.

Ease of Navigation: Easy to navigate with links to information about other moons.