Pluto's Atmosphere Shrinks 16% as It Enters an 88-Year Colder Stretch
Updated
Updated · Universe Today · Aug 8
Pluto's Atmosphere Shrinks 16% as It Enters an 88-Year Colder Stretch
3 articles · Updated · Universe Today · Aug 8
Summary
Recent occultation data show Pluto’s atmospheric pressure fell 16% between mid-2021 and July 2023, marking the clearest sign yet that its long-stable atmosphere has begun thinning.
Scientists link the drop to Pluto’s entry into colder, darker regions of its 248-year orbit, where less sunlight lets its mostly nitrogen atmosphere contract and gradually freeze toward the surface.
The pressure had held near 1 Pascal from the 2015 New Horizons flyby through about 2021, but newer light curves also show changes in the lower atmosphere consistent with haze particles settling.
Because Pluto’s atmosphere is only about 1/100,000 of Earth’s surface pressure, researchers must track it through rare stellar occultations, measuring how starlight dims and reappears through the haze.
Models now suggest Pluto may retain some atmosphere rather than collapse completely, but scientists say more occultation measurements over coming years and decades are needed to confirm the trend.