Mason professor investigates Pluto’s atmosphere

This story was originally published in the Nov. 10 issue of Fourth Estate.

A Mason astrobiology and astronomy professor is part of a NASA-funded mission to learn more about Pluto’s atmosphere.

Professor Mike Summers is one of the 24 co-investigators on the New Horizons Pluto–Kuiper Belt Mission and the only person from Mason on the team.

“I’ve been involved in this particular mission since about 2003,” Summers said. “We started discussing the possibility of a mission in 1994, so it’s been a good 20 years.”

The other scientific investigators include organizations such as Southwest Research Institute and professors from MIT, Johns Hopkins University, Stanford University, Washington University and the University of Colorado.

According to Summers, Congress denied funding for the Pluto project in 2001, but then NASA approved funding in 2003. The spacecraft was launched in 2006, and after almost 10 years, it will reach Pluto in July 2015.

“When we launched it, it was the fastest spacecraft that has ever left Earth,” Summers said. “A year later it passed through the orbit of Jupiter, which is five times the distance between the Earth and the Sun. Now we’re here at 2014 and we’re still a year away from Pluto.”

The spacecraft has six instruments to photograph and study Pluto’s atmosphere. According to Summers, the goal of this mission is to know what makes up the atmosphere and surface of Pluto.

“It’s about the size of a small car and it has a large antennae on one side of it, it’s pointed to Earth to communicate with,” Summer said. “On the other side, is the nuclear power package which has nuclear material that actively decays and gives off heat and that’s what power the spacecraft.”

Summers said that the science community has recently discovered that Pluto is one of many dwarf ice planets in our solar system. There could be as many as 100,000, which would make it the most common planet in our solar system. Another known characteristic of Pluto is that it is very far away, cold, small, made out of icy materials and has a large atmosphere.

“We know it has an atmosphere and it’s mostly methane and nitrogen and the atmosphere is very extended,” Summers said. “The atmosphere of the Earth is very thin, about 10 kilometers thick. Pluto’s atmosphere extends out about ten times its radius, so the volume of the atmosphere is about a 1,000 times the volume of the planet.”

According to Summers we also know that the planet is built of debris from the formation of the solar system, including comets that hit the Earth. Pluto may even be actively losing some of its atmosphere due to evaporating ice pockets. But in 2006, the International Astronomical Unit demoted Pluto from planet status. The IAU is the largest body of astronomers in the world, however their decision has sparked debate about Pluto amongst planetary scientists. Summers still considers Pluto a planet.

“They [the IAU] came up with a criteria of what consists a planet. One thing it had to be round, it had to be an orbit around the Sun, but it also had to clear out its orbit out of other material. Well its orbit [Pluto’s] intercepts the orbit of Neptune…and because of that Neptune is considered a planet and Pluto isn’t. So it’s a very odd type of way of defining what planets are because it matters where the planet is, not in terms of what it is,” Summers said. “Also we found that perhaps the largest number of planets in our galaxy are free floating planets [planets that have no orbit]. So according to IAU, those are not planets either. So the definition doesn’t make much sense.”

But Summers thinks that Pluto’s demotion to a dwarf planet has brought more interest about small planet. Planetary scientists are finding a variety of planets, including Pluto, that do not fit into the categories of terrestrial or gaseous planets. Mercury, Venus, Earth and Mars are terrestrial planets, and Jupiter, Saturn, Uranus and Neptune are the giant gas planets.

“The idea of what constitutes a planet was never a question when I grew up,” Summers said. “But now… we weren’t prepared for the kind of planets we’re finding. Planets that are all water, planets that are all metal, planets that appear to be made out of something as lightweight as Styrofoam, we find planets that are made out of diamond, we find some planets that circle two stars, some of them [circle] four stars and the diversity is almost unreal. Looking at our solar system we were never prepared for this range of planets.”

So does all of this diversity mean there is life somewhere else in our solar system? Not quite. There are many planets and moons that are considered to be habitable, but that isn’t proof of other life forms. There are four places in our solar system where Earth-type microbes can be habitable.

“That would be the sub surface of Mars, Europa which is a moon of Jupiter, probably Ganymede and Callisto which are other moons of Jupiter, the sub surface of Titan which is a moon of Saturn and then there are two other moons of Saturn that are small, Mimas and Enceladus, that we know have subsurface oceans,” Summers said.

Water is the building block of life and there is actually more water in our solar system then previously expected. Summers said there is enough water to dup about a 100 billion oceans of water on every planet in our universe. Most of this water ends up in planets made completely out of water or dwarf ice planets, like Pluto.

“To me if we have life out there that would be amazing, but if we don’t that’s pretty astonishing as well,” Summers said. “If we’re it then that’s pretty sobering, but if there’s life everywhere then that’s pretty interesting as well. So it’s like a win-win situation. Whatever we find will be exciting.”

Other professors involved in the project were contacted to comment on the mission, however after two recent accidents involving NASA, they were unavailable. These accidents will not explicitly affect the Pluto mission.

“The loss of the two commercial vehicles and the pilot doesn’t directly influence the Pluto mission. But that loss is significant for future plans for NASA to use commercial organizations for future missions.  Many of us had detailed plans and even instrumentation under development to fly on the commercial space planes like the Virgin one that crashed,” Summers said.

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Illustration by Laura Baker