This could even be the \u201cfirst signs of Pluto\u2019s atmospheric collapse,\u201d according to a statement<\/a> by the Planetary Science Institute. The institute\u2019s senior scientist Amanda Sickafoose led the latest work.<\/p>\n When the stars align <\/p>\n Stellar occultations occur when something like a planet, moon, ring, or asteroid blocks the light from a star, which might sound really trivial as far as eclipses are concerned. But occultations actually allow researchers to study these foreign systems with \u201cspatial resolutions of a few kilometers\u2014several orders of magnitude better than the resolution of any other Earth-based method,\u201d according to an explainer<\/a> by the MIT Planetary Astronomy Lab.<\/p>\n Other than New Horizons\u2019s flyby, Pluto, being as far away as it is, appears to be \u201cnothing more than a tiny blob\u201d for humanity\u2019s best telescopes, the statement explained. That said, occultations have allowed astronomers to successfully compare and contrast fluctuations of Pluto\u2019s atmospheric pressure since as early as 1989, the paper noted.<\/p>\n \u201cI\u2019m constantly amazed at how the simple technique of watching starlight dim and reappear allows us to study a thin atmosphere\u2014a few millionths of the Earth\u2019s\u2014on a world two-thirds the size of our Moon and 30 times farther from the Sun,\u201d Sickafoose said in the statement.<\/p>\n Comparing transit notes <\/p>\n For the study, the team recorded 10 different occultations of Pluto between 2017 and 2023, four of which were the same event captured from multiple locations on Earth. Pluto has a primarily nitrogen atmosphere with a few carbon-based compounds, which combine to form a thin haze encircling the dwarf planet. Sickafoose explained that scientists have yet to fully understand Pluto\u2019s atmospheric physics.<\/p>\n However, Pluto\u2019s icy surface strongly suggests that decreased atmospheric pressure should drive the haze thinner and to lower altitudes, the team wrote in the paper. In the context of occultations, haze particles scatter light like fog, which astronomers can observe as Pluto\u2019s atmosphere bends the star\u2019s light. Then, the researchers tried fitting their observations to atmospheric models.<\/p>\n An ongoing journey <\/p>\n The analysis showed that Pluto\u2019s atmospheric size and pressure increased between 1988 and 2015. Then until about 2021, the atmosphere stayed more or less consistent. These results are consistent with previous research<\/a> that found a plateau in Pluto\u2019s atmospheric evolution. However, by 2022, there was a clear deflation in Pluto\u2019s atmospheric parameters, by as much as 16%. This was a possibility discussed as early as 1996<\/a>\u00a0and more recently in 2021, when another team of astronomers suggested<\/a> that Pluto\u2019s atmosphere has been \u201cfreezing out\u201d since 2018.<\/p>\n \u201cWe\u2019re at a particularly interesting point for Pluto,\u201d Sickafoose said. \u201cOur work suggests that the atmosphere has recently started decreasing in pressure. I am hopeful that we\u2019ll be able to get more data in the next years to decades to specifically confirm or refute this trend.\u201d<\/p>\n And astronomers should have more than enough time. Pluto won\u2019t be getting any closer to the Sun until at least the year 2114. So, in the following years we\u2019ll likely see whether Pluto\u2019s atmosphere will literally falter out at its farthest distance from the Sun.<\/p>\n![\"Pluto](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/08\/pluto-occultations.jpg\")
Maps showing paths of Pluto\u2019s occultation shadows. The solid lines indicate the top, middle, and bottom of Pluto\u2019s shadow on each date, and the arrows near the bottom of the image show the direction of motion of the shadow. The black dots are the closest approaches of Pluto to the Earth in the centers of the shadow paths. Credit: A. Sickafoose\/Planetary Science Institute <\/p>\n