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American astronomer Clyde Tombaugh discovered Pluto in 1930 at the age of 24

He died in 1997, and NASA's New Horizons probe is carrying some of his ashes

The spacecraft flew closest to Pluto on Tuesday

CNN  — 

When a NASA probe whizzed past Pluto on Tuesday, the man who discovered the dwarf planet 85 years ago was there.

A small amount of the ashes of American astronomer Clyde Tombaugh are on board the New Horizons spacecraft, which has spent more than nine years traveling to the outer reaches of the solar system.

The probe soared within about 7,800 miles (12,500 kilometers) of Pluto’ s surface, the closest any spacecraft has been to the icy world, beaming back data and images.

Rewind to 1930, and Pluto wasn’t even on the solar system map.

Tombaugh, who grew up on a farm in Kansas, was working at Lowell Observatory in Arizona. Previously an amateur astronomer, he had been hired to help find a planet beyond Neptune.

Studied millions of images

His work involved thousands of hours spent pouring over millions of images of stars, according to the Johns Hopkins University Applied Physics Laboratory, which is managing the New Horizons mission for NASA.

Clyde Tombaugh discovered Pluto on February 18, 1930 at the Lowell Observatory in Flagstaff, Arizona.

Tombaugh made the landmark discovery on February 18. He was 24 at the time.

The breakthrough helped advance human understanding of the solar system. Scientists now think that there are thousands of other icy objects in the outer region of the Solar System known as the Kuiper Belt, of which Pluto is the largest known object.

The New Horizons spacecraft is headed deeper into the band of objects after Tuesday’s flyby of Pluto.

Tombaugh died in 1997. He was 90.

‘He would have been astounded’

Nine years later, in 2006, New Horizons began its epic voyage.

Some of his ashes were put in a canister about 2 inches wide and 1.5 inches tall that was attached to the inside of the piano-sized spacecraft’s upper deck.

“When he looked at Pluto, it was just a speck of light,” Annette Tombaugh, his daughter, said earlier this year. “To actually see the planet that he had discovered and find out more about its atmosphere, find out more of what it is and actually get to see the moons of Pluto, he would have been astounded.”

The canister bears an inscription from Alan Stern, the head of the New Horizons mission: “Interned herein are remains of American Clyde W. Tombaugh, discoverer of Pluto and the solar system’s “third zone.” Adelle and Muron’s boy, Patricia’s husband, Annette and Alden’s father, astronomer, teacher, punster, and friend: Clyde W. Tombaugh (1906-1997).”