Published: Feb. 13, 2005

The University of Colorado at Boulder will mark the 75th anniversary of the discovery of the planet Pluto on Feb. 18 with a 4 p.m. event at the site of the Colorado Scale Model Solar System, a unique scale-model walking tour of the solar system.

The anniversary celebration will be held just west of the Math Building on campus, where the model of Pluto is located.

The celebration of the discovery of Pluto 75 years ago by the late astronomer Clyde Tombaugh also coincides with the installment in the last week of a CU-Boulder student instrument on NASA's New Horizons spacecraft for a January 2006 launch to Pluto.

Laid out on a scale of 1 to 10 billion, the 500-meter solar system walking tour features the sun and all nine planets and stretches from Fiske Planetarium north to the Math Building near the intersection of Colorado Avenue and Folsom Street.

Designed to detect dust grains produced by collisions between asteroids, comets and Kuiper Belt objects, the Student Dust Counter is the first science instrument on a NASA planetary mission to be designed, built and flown by students, said CU-Boulder Professor Mihaly Horanyi of the Laboratory for Atmospheric and Space Physics.

"This is an exciting time for CU to be celebrating Pluto," said Horanyi, the faculty mentor for the Student Dust Counter and a professor in the physics department. "It's another great opportunity for our CU-Boulder students, who have a long history of involvement in NASA missions."

The event also will include Fran Bagenal, a professor in the astrophysical and planetary sciences department, Alan Stern, principal investigator for the New Horizons mission and several CU-Boulder students involved in the mission. Stern is the director of space studies at the Southwest Research Institute in Boulder and a CU-Boulder adjunct professor in APS.

Tombaugh became the only American to discover a planet when he detected Pluto on Feb. 18, 1930, in a series of photo plates taken at the Lowell Observatory in Flagstaff, Ariz. The discovery capped a quarter century-long effort to find a planet beyond Neptune's orbit and opened the door to other discoveries in the region including Pluto's moon, Charon, and more than a thousand other objects in the region now known as the Kuiper Belt.

The New Horizons mission was developed by the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. The spacecraft is slated to swing past Jupiter in February 2007 and should reach Pluto and Charon as early as July 2015. NASA administrators also may direct New Horizons to fly deeper into the Kuiper Belt to study one or more of the icy, rocky objects in that distant region.

"With faculty supervision, the students will also distribute data from the instrument and lead a comprehensive effort to bring their experiences to classrooms of all grades over the next two decades," said Horanyi.

"Clyde Tombaugh's achievement was a uniquely American one that involved pluck and perseverance, and which will stand forever in the history of planetary science," says Stern. "We look forward to exploring Pluto-Charon and the Kuiper Belt with New Horizons, as only NASA and the United States can."

For more information on the mission, visit the web at: . Pluto facts and figures can be found at: .