Could Pluto Become a Planet Once Again?
Not Yet Explored
Last Wednesday, Dr. Alan Stern told a sold-out audience at at COSI’s National Geographic Giant Screen Theater how lucky they are.
“You live in a very special time in which we are opening up the Solar System,” said Stern.
Almost two years ago, Stern, the principal investigator for NASA’s New Horizon mission, directed the first exploration of Pluto. The planet – or dwarf planet, depending on your preference – had long been a mystery until Stern’s team flew New Horizons past it in the summer of 2015.
Finally, the amorphous, pixilated dot in telescope photos could be seen for the complex, diverse world it’s always been, with mountains, an atmosphere, and a giant heart-shaped glacier roaming across its surface. For 15 years, Stern and his team of 2,500 men and women worked to bring the people of Earth the first clear photographs of the dark, distant and controversial world.
At his lecture, hosted by OSU’s Center for Cosmology and Astro-Particle Physics, Stern made sure the audience was immersed in the story of Pluto, and the mystery. He explained how, in 1930, an astronomer at the Lowell Observatory in Flagstaff, Arizona named Clyde Tombaugh discovered a ninth planet in the Solar System. Astronomers had long suspected a ninth planet existed in the far reaches of our star system, and Tombaugh’s predecessors had spent entire careers looking for it. Tombaugh found it in nine months.
Named after the Roman god of the underworld by an English schoolgirl, Pluto spent the next 85 years as an unreachable and unknowable point of light in the sky. Even the mighty Hubble Telescope could only depict it as a blob of pixels. In the 1980s, the US Postal Service released a series of stamps portraying each of the planets. Pluto’s stamp was shown as a nondescript, tan orb with the infuriating words “Pluto – Not Yet Explored.”
The Pluto Salute
Stern said his office gets about 10 or 20 requests a week for lectures like Wednesday’s. Stern can’t do all of them, of course, and not all speaking engagements are alike. Some are more technical, for astronomical professionals. Some are webinars or talks with elementary school classes. But Stern said since the Pluto mission, there’s been a steady stream of interest in lectures about the ninth planet.
“One thing we do a lot of is storytelling,” said Stern. Not just the story of Pluto itself, but of the people who finally explored it.
“New Horizons set a record for the number of women engineers on a space mission ever,” said Stern. “Almost our entire flight control team was women. That’s almost unheard of. So we tell lots of different stories.
Stern’s lecture was imbued with an understated, but ever-present, sense of patriotism. When placing New Horizon at the end of a long string of planetary missions, Stern reminded the audience, “In the space of 60 years – the lifetimes of some of the people in this room – your country explored the entire Solar System.”
It’s also present in Stern’s willingness to find the elusive time to travel the country engaging with the public.
“It’s the people of this country who pay for this stuff,” said Stern. “So I feel it is an obligation for those of us who lead it to go out and communicate it.”
Stern has no problem engaging with the inevitable audience questions regarding Pluto’s “status.”
“You guys don’t actually believe that dwarf planet stuff, right?” said Stern.
Stern’s measure of a planet is what he calls the “Star Trek test,” which references how the crew of the starship Enterprise never stewed over whether the object they were approaching was a planet or not. Basically, you know a planet when you see one, and Pluto passes the test.
For an informal poll of the crowd, Stern asked the true Pluto believers to lift up nine fingers – the “Pluto salute.” The election results were clear. Pluto remained, for the evening, planet nine.
The Far Side
Stern and his fellow scientists spent years trying to get enough money to erase the “Not Yet.”
“If you go to NASA and say, ‘Let’s go to Pluto because we haven’t been there,’ you’ll get laughed out of the building,” said Stern. “Because there’re lots of places we haven’t been.”
It was the discovery that Pluto is not alone – that in fact, Pluto is one of thousands of objects orbiting in the distant Kuiper Belt – that made the Solar System’s misfit a prime target for exploration.
“Pluto’s not the smallest,” Stern declared. “It’s the biggest of the little ones.”
Sending a spacecraft to Pluto would not only unlock its secrets, but the secrets of a whole new class of objects in the Solar System that somehow went unnoticed by astronomers until the 1990’s. New Horizons went to the top of the list, but there was a catch; the team would have to build the fastest spacecraft ever, for a fraction of the cost of its predecessors, and they would have to do it in four years.
The New Horizons team toiled on obscurity for four years before launching the spacecraft in 2006, and spent another nine years guiding it to its destination. When it finally arrived at Pluto in 2015, New Horizons carried with it the ashes of Clyde Tombaugh and one of those stamps that had long taunted planetary scientists; “Pluto – Not Yet Explored.” It sent back photographs that ended up on the front pages of newspapers around the world, but the picture of Pluto that Stern calls his favorite is probably not the most iconic.
It’s a dark photograph of Pluto’s shadow, backlit by the sun, circled by a blue atmosphere. It’s Stern’s favorite because, “You can only get this picture from the far side of Pluto.”
Photos by Jesse Bethea.