Using NASA New Horizons spacecraft data and digital elevation models of Pluto and its largest moon Charon, mission scientists created this flyover movie.
FLAGSTAFF, Az. – Whether Pluto is officially a planet is the least interesting thing about the runt of the solar system, astronomers will tell you 95 years after the discovery of the fascinating and sometimes controversial world.
Percival Lowell founded the Lowell Observatory in Flagstaff, Arizona, in 1894 because he was fascinated with Mars. However, nearly 100 years later, the facility is best known as the home of Pluto.
Lowell was searching for “Planet X,” believed to be hiding on the solar system’s outskirts beyond Neptune in an area known as the Kuiper Belt. It wasn’t until 1930, about 15 years after Lowell’s death, that another Lowell Observatory astronomer, Clyde Tombaugh, would find Pluto.
“Interestingly, once the planet had been found, they went back to old photographs that had been taken before Percival Lowell had passed away. And they did so-called ‘pre-covery’ discovery to say, ‘Here it was on this picture we took back in 1915, and we just didn’t realize that it was that thing,’” Lowell Observatory Director of Science Gerard van Belle said.
The Lowell Observatory’s Marley Foundation Astronomy Discovery Center in Flagstaff, Arizona.
(Abe Snider // Lowell Observatory)
For the sixth year in a row, Lowell Observatory is hosting the I Heart Pluto Festival, throwing a big party to celebrate its discovery and the 10th anniversary of NASA’s New Horizons spacecraft flyby, the only mission to the little world.
The highest-resolution color departure shot of Pluto’s receding crescent from NASA’s New Horizons spacecraft, taken when the spacecraft was 120,000 miles away from Pluto in July 2015.
(NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
The dwarf planet was there all along, waiting to be discovered, but it wasn’t what astronomers thought they would find. Pluto is just 1,400 miles wide, about half the width of the U.S.
“It definitely kind of broke the mold,” van Belle said. “In our inner solar system, we have the four terrestrial rocky planets between Mercury, Venus, Earth and Mars. And then we have these four gas giants, these kind of big lumps of hydrogen, helium. It was expected that with the next thing found, it’s going to also be this big puffy thing, and Pluto’s this little runt.”
Little world, big heart
The declassification of Pluto was, like the world itself, a bit of an oddball moment in astronomy.
A vote at the 2006 International Astronomical Union conference stripped Pluto of its planet title, dubbing it a dwarf planet because other bodies larger than Pluto were discovered in the solar system.
Van Belle, who specializes in stars, participated in the vote and described the last-minute chaos surrounding it.
“You don’t vote for words in science. And so the whole thing was kind of weird to start off with,” he said.
The vote happened on the last day of a two-week IAU meeting when only about 400 people were left, van Belle estimated.
Pluto nearly fills the frame in this image from NASA’s New Horizons spacecraft. The image was taken on July 13, 2015, when the spacecraft was 476,000 miles (768,000 kilometers) from the surface. This is the last and most detailed image sent to Earth before the spacecraft’s closest approach to Pluto on July 14.
(NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute Image)
“There were many people, like me, who study stars. I don’t know crap about planets. And we’re asked to vote on this word that’s not really part of our wheelhouse,” he said, adding he voted against the de-classification.
But turning our nine-planet solar system into eight just earned Pluto more fans.
This year also marks the 10th anniversary of Pluto’s first dedicated flyby mission. NASA’s New Horizons spacecraft zoomed by the small world and its moons, providing the first high-resolution images of its complex surface features and atmosphere.
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One of the most memorable images taken by New Horizons is that of Pluto’s “heart” feature. The heart-shaped glacier, nicknamed Sputnik for Earth’s first human-made satellite, is nearly 600 miles wide. NASA said it’s the largest known glacier in our solar system.
This image of haze layers above Pluto’s limb was taken by NASA’s New Horizons spacecraft. About 20 haze layers are seen.
(NASA)
Images of Pluto’s icy heart have appeared on screensavers and T-shirts and have been shared by news media worldwide.
Even without its planet title, Pluto has all the things you would expect from one, van Belle said. Scientists continue to mine data from New Horizons to study the mountains, glaciers and weather on Pluto.
With no plans for another Pluto mission, NASA’s most powerful eyes in space, the James Webb Space Telescope, will be the next to study the oddity of the solar system.