1930 Clyde Tombaugh, A 25-year-old amateur astronomer, spied on a small, dim object in the night sky.
He worked in Lowell Observatory in Flagstaff, Arizona, about a year ago when he used a blinker comparator – a special type of microscope that can examine and compare images – to see what was once considered the ninth planet in our solar system: Pluto.
By all accounts, Pluto was – well – weird. At one point, astronomers believed it could be larger than Mars (it isn’t). It is known for its unusual 248-year orbit cross Neptune’s path. Today, Pluto is recognized as the largest object in the Kuiper Belt – but is no longer considered a planet.
In 2006 International Astronomical Union voted to reduce Pluto, defining the planet as a body orbiting the sun, is round in shape and “cleared the neighborhood around its orbit” – meaning it has become gravitationally dominant, so there are no bodies of its own moons in its orbital zone. Since Pluto did not mark this third frame, it was considered a dwarf planet.
Now a new concept mission handed over to NASA aims to take a closer look at Pluto and its nearby systems. Proposed at the end of 2020, Persephone will investigate whether Pluto has an ocean and how the surface and atmosphere of the planet developed.
Persephone would send a spacecraft armed with high-resolution cameras into orbit around Pluto for three years and map its surface as well as the surface of its largest moon, Charon.
But why is Pluto worth a visit?
The same year that Pluto was ejected from its planetary pedestal, NASA sent it New Horizons mission to Pluto and the Kuiper Belt to better understand the outer edge of our solar system.
Coming to Pluto in 2015, New Horizons hit what was a scientific treasure. Close-ups of Pluto revealed potentially active mountain ranges, icy waters and surprising data about them geological history of its surface.
Carly Howett, the planetary physicist and principal investigator Persephone, says New Horizons have shown us how complex that part of space actually is.
“It’s not that New Horizons basically has new technology, but it’s kind of given people an insight into what Pluto’s system might be like,” says Howett. “The world saw Pluto for the first time.”