NASA scientists are just now starting to play with the data collected by the New Horizons spacecraft on its flyby of Pluto in July. What they’ve found so far is that the dwarf planet is either undergoing some crazy physics freak out spell, or that their measurement models need a little testing.
Pluto’s Atmosphere perplexes NASA scientists
The data puzzles come in the form of measurements regarding Pluto’s atmospheric pressure. Eliot Young, a planetary scientist from the Southwest Research Institute (SwRI) in Boulder, Colorado, organized a team of astronomers in June to study Pluto’s atmosphere by watching it pass a distant star. Working from Australia and New Zealand, the group observed what happened to the star’s light as Pluto went by and then proceeded to use those observations to calculate how much gas is present in Pluto’s atmosphere.
Planetary scientists have been using this method since 1988, and their findings tell them that Pluto’s atmosphere has been growing steadily denser over the past 27 years. The results of Young’s work in June align with that trend. His team determined the atmospheric pressure on Pluto to be 22 microbars (0.022 pascals), which equates to 22-millionths the pressure on Earth at sea level. Don’t worry about Pluto; Pluto sounds pretty relaxed.
Probe vs. People
But the data from the New Horizons flyby suggests that Pluto is under even less atmospheric pressure, only 5 microbars, down from the 22 measured on Earth. The discrepancy could be explained in part by the indirect way scientists on Earth calculate the surface pressure. Their measurements work to find pressure at around 50-75 kilometers above the surface. Researchers then make a few assumptions about the structure of Pluto’s atmosphere in order to calculate the number at the surface.
The New Horizons spacecraft, however, calculates surface pressure directly. It measured the bend of radio waves beamed from Earth as they passed through Pluto’s atmosphere and made their way to NH on the far side of the dwarf planet. Researchers are now tasked with establishing exactly why the numbers differ, which means putting their mathematical models to the test. It will require patience, given that most of the flyby data is still on board New Horizons, which could include the key to this problem. The slow transmission speeds mean that it will take months to get all the information back to Earth.
Dig the Video
Until then, we can at least appreciate the stunning visuals gathered by the probe. A video of the icy dwarf planet has been released that offers us a beautiful, if not mathematical, vantage on Pluto’s atmosphere. Even so, these images have revolutionized the way researchers are thinking about the dwarf planet; there’s a possibility it could still be geologically active. Hurry up, New Horizons!
