James Webb Space Telescope (JWST) observations indicate that Pluto’s atmosphere is unlike any other in the solar system, confirming a 2017 hypothesis and potentially revealing how the early Earth developed a habitable atmosphere from its nitrogen and hydrocarbon beginnings.
Pluto is covered in a haze of nitrogen, methane, and carbon dioxide, whose individual particles regulate the atmosphere’s energy balance as they heat and cool. Other JWST observations are equally unusual, showcasing volatile cycles of surface ice redistribution and Pluto’s satellite Charon sucking away part of its host’s atmosphere.
Studying Pluto
A new series of studies from a group of international researchers illuminated Pluto’s strange goings-on this spring. Yet one person was not surprised, at least by the discovery of Pluto’s unusual atmosphere. That person is Xi Zhang, a professor of Earth and planetary sciences at UC Santa Cruz, who predicted such conditions back in 2017. Zhang’s prediction was developed from his analysis of data from NASA’s New Horizons flyby in 2015, which provided the most detailed information about Pluto available at the time.
Zhang published his theory of a unique haze particle atmosphere in a 2017 paper, predicting how the heating and cooling of these particles control Pluto’s atmospheric energy balance.
Confirming an Unlikely Theory
“It was a crazy idea,” said Zhang, noting that many in his field considered his proposition unlikely. Yet at the time, he also suggested a way that future astronomers with more powerful equipment could verify if his theory were true by noting that intense mid-infrared radiation should emanate from Pluto if the haze were indeed cooling the dwarf planet. He didn’t have to wait too long, as the December 2021-launched JWST eventually proved to be an instrument capable of making the detection.
“We were really proud, because it confirmed our prediction,” Zhang said. “In planetary science, it’s not common to have a hypothesis confirmed so quickly, within just a few years. So we feel pretty lucky and very excited.”
Unexpected Observations
That 2015 flyby also revealed many unanticipated discoveries. Pluto’s surface features continual geological activity and a complex topography. Glaciers of nitrogen and methane exist under an atmosphere formed by the photochemistry of these two elements, with carbon monoxide also present in the haze.
The flyby also inspected Charon, revealing a more homogeneous surface with large amounts of water ice and ammonia-based compounds but lacking an atmosphere. Charon also revealed interaction with its host planet, as the satellite’s polar regions feature a reddish hue because of methane absorbed from Pluto’s atmosphere.
The new look provided by JWST captured Pluto and Charon with its MIRI instrument, confirming the suspected mid-infrared emission. Further imaging focused on Pluto alone enabled detailed spectral analysis of the dwarf planet’s atmosphere with a precision impossible from earlier instruments, providing valuable information on Pluto’s ice.
A Second Prediction Confirmed
A second prediction made by Zhang’s student at the time, Linfeng Wan, and published in a 2023 paper, also found validation in the new James Webb Space Telescope observations. That paper made predictions regarding Charon’s rotational light curve amplitude, upheld by light curve data collected by JWST and presented in the latest papers this spring.
“Pluto sits in a really unique spot in the range of how planetary atmospheres behave. So this gives us a chance to expand our understanding of how haze behaves in extreme environments,” Zhang explained. “And it’s not just Pluto—we know that Neptune’s moon Triton and Saturn’s moon Titan also have similar nitrogen and hydrocarbon atmospheres full of haze particles. So we need to rethink their roles, too.”
“Before oxygen built up in Earth’s atmosphere, about 2.4 billion years ago, life already existed,” Zhang added. “But back then, Earth’s atmosphere was totally different—no oxygen, mostly nitrogen, and a lot of hydrocarbon chemistry. So by studying Pluto’s haze and chemistry, we might get new insights into the conditions that made early Earth habitable.”
Beyond just having their predictions proven correct, Zhang and Wan contributed theoretical modeling to one of the recent papers in Nature Astronomy that substantiated their earlier predictions.
The paper “Evidence of Haze Control of Pluto’s Atmospheric Heat Balance from JWST/MIRI Thermal Light Curves” appeared on June 02, 2025, in Nature Astronomy.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.
memoment editorial note: This article examines the cutting-edge world of military technology, DARPA breakthroughs, and secret research programs monitored globally by memoment.
This article was curated by memoment.jp from the feed source: The Debrief.
Original article: https://thedebrief.org/it-was-a-crazy-idea-james-webb-space-telescope-confirms-dramatic-phenomenon-on-pluto/
© All rights belong to the original publisher.
