Pluto’s atmosphere update! It’s thinning
Scientists detected Pluto's atmosphere is thinning as it moves farther away from the sun in its orbit. They did so when Pluto passed in front of distant stars. The post Pluto’s atmosphere update! It’s thinning first appeared on EarthSky .
Scientists have discovered that Pluto’s atmosphere is thinning, according to a recent study led by Amanda Sickafoose of the Planetary Science Institute. The research, published on July 31, 2026, reveals that the atmospheric pressure on Pluto decreased by 16% between mid-2021 and July 2023. Pluto’s atmosphere, which is mostly composed of nitrogen, was found to be thin when NASA’s New Horizons spacecraft flew by the dwarf planet in 2015.
The researchers measured the change in atmospheric pressure by observing Pluto’s occultation, or passing in front of, distant stars. By analyzing starlight as it was bent by Pluto’s thin atmosphere, the researchers could detect the atmospheric pressure decrease. The study examined how Pluto’s atmosphere has changed between 2017 and 2023, finding that while the pressure remained constant from the New Horizons flyby in 2015 to mid-2021, it began decreasing afterward.
This thin, hazy atmosphere of Pluto, which was first observed by New Horizons, is expected to continue thinning and eventually freeze onto its surface as the dwarf planet moves away from the sun and into a colder part of its orbit.
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