Scientists Confirm Pluto’s Nitrogen Atmosphere Has Begun Shrinking: Planetary Science Institute Team Led By Amanda Sickafoose Uses Stellar Occultations To Track Thinning. Haze Layers Settling Lower Toward Surface May Never Completely Freeze Out
According to Universe Today, scientists led by Planetary Science Institute Senior Scientist Amanda Sickafoose have confirmed that Pluto’s mostly-nitrogen atmosphere has begun shrinking in pressure, with observations showing a 16 percent drop between mid-2021 and July 2023.
Pluto is beginning an 88-year march through colder, darker regions of the outer Solar System following its 2015 perihelion passage. The atmospheric pressure held steady at around ten millibars; approximately 1/100,000 of Earth’s; from the 2015 New Horizons flyby through roughly 2021, before beginning its decline. The team’s paper notes a 7 percent pressure drop at 1,275 km altitude from 2015-2022, and a 16 percent drop at 1,215 km altitude through 2023.
The team tracks these changes using stellar occultations; events when Pluto passes in front of a distant star, allowing the light to pass through its tenuous atmosphere and reveal details about haze thickness, density and structure. The latest occultations show haze particles settling toward the surface and changes in the lower atmospheric structure consistent with particles settling over yearly timescales.
“We’re at a particularly interesting point for Pluto,” said Sickafoose. “Our work suggests that the atmosphere has recently started decreasing in pressure. I am hopeful that we’ll be able to get more data in the next years to decades to specifically confirm or refute this trend.”
An atmosphere 1/100,000 the thickness of Earth’s and it is visibly thinning in real time. Check out our previous coverage of science on The Trusted Times.
