NASA
Nasa Star Child: Who's Who in Space (Level 2)
This site provides a list of people who have given their lives to studying space science. Each person has a biography that you can read.
NASA
Nasa Star Child: Who's Who in Space (Level 1)
StarChild presents biographies of people who have contributed to space exploration from Tycho Brahe to Sally Ride.
Famous Scientists
Famous Scientists: Clyde Tombaugh
Find out about Clyde Tombaugh, the scientist who discovered the dwarf planet Pluto in 1930, and also discovered a number of asteroids.
Children's Museum
Children's Museum: Field Guide to the Universe: Astronomers
Read brief biographies of astronomers who are grouped by time period.
Other
Observatorio Arval: Clyde Tombaugh
This is a biography page for the American astronomer and discoverer of Pluto, Clyde Tombaugh.
Wikimedia
Wikipedia: Pluto
Wikipedia, a publicly-maintained encyclopedia, provides an article on the dwarf planet, Pluto, including images, physical characteristics, history of its naming, the planet/dwarf planet debate, and more.