Scientists have discovered that Pluto’s atmosphere is already thin.
REPUBLIKA.CO.ID, TEXAS — A new study shows gases around Pluto now slowly disappearing, turning to ice as the dwarf planet moves away from the Sun. Reported from Sciencealert, Thursday (7/10), as the temperature drops at the surface, this seems to cause the nitrogen to freeze again, causing the atmosphere to fade.
Scientists know this when observing it using the technique of occultation, which uses a distant star as a backlight for telescopes on Earth to see what is happening on Pluto. It is a tried and tested observation technique that is used extensively in astronomy.
“Scientists have used occultation to monitor changes atmosfer Pluto since 1988,” said planetary scientist Eliot Young of the Southwest Research Institute (SWRI) in Texas.
“Mission New Horizons has achieved an excellent density profile since its 2015 flyby, consistent with Pluto’s atmospheric mass doubling every decade, but our 2018 observations do not show that the trend has continued since 2015,” he said.
Pluto’s atmosphere is formed from ice that evaporates on the surface, with small changes in temperature causing significant changes in the mass density of the atmosphere. The largest nitrogen glacier known is Sputnik Planitia, the western part of the heart-shaped Tombaugh Region visible on Pluto’s surface.
Pluto currently takes 248 Earth years to make one orbit around the Sun, at one point being as close as 30 astronomical units (AUs) from the Sun – that’s 30 times the distance between Earth and the Sun.
That distance is getting further away, leaving Pluto with less sunlight and lower temperatures. The increase in atmospheric density seen in 2015 is most likely due to thermal inertia – residual heat trapped in nitrogen glaciers that has a delayed reaction to the increasing distance between Pluto and the Sun.
“An analogy for this is the way the Sun heats the sand on the beach. The sun’s rays are most intense during the day, but the sand then continues to absorb heat throughout the afternoon, so it’s hottest in the afternoon,” said SwRI planetary scientist Leslie Young.
In recent years, astronomers have been able to confirm that there are snowcapped mountains on Pluto and liquid oceans beneath its surface. These two things can tell how the dwarf planet’s atmosphere works.
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