16% Smaller: Pluto's Atmosphere Has Sharply Shrunk

Icy Collapse: Astronomers Report Pluto's Atmosphere Is Beginning to Collapse

According to НВ — Техно: This article was published on August 5 at 10:00.

Using measurements from stellar occultations, a team led by Amanda Sickafoose of the Planetary Science Institute in the U.S. has found that Pluto's atmosphere has begun to deteriorate. It started compressing around mid-2021, and by 2022 its atmospheric parameters had dropped by 16 percent. The likely explanation is that Pluto is drifting farther from the Sun.

The analysis drew on data collected by New Horizons when it flew past Pluto in 2015. The team tracked ten occultations between 2017 and 2023, including four observed simultaneously from different locations on Earth. Pluto's atmospheric size and pressure expanded steadily from 1988 to 2015, then flattened out until roughly 2021. This tenuous envelope is composed mainly of nitrogen, with traces of carbon compounds, and its density is only a few millionths that of Earth's atmosphere.

Why Pluto's Distance From the Sun Matters

Pluto follows a 248-year orbit and is currently moving away from the Sun; its next closest approach is not expected until at least 2114. Scientists predicted this atmospheric collapse as long ago as 1996, and in 2021 another research group proposed that Pluto's atmosphere had been freezing since 2018.

“I remain endlessly impressed that such a simple method - watching a star's light blink out and return - lets us examine a mere wisp of an atmosphere, a few millionths as dense as Earth's, on a world two-thirds the size of our Moon and 30 times farther from the Sun.”

- Amanda Sickafoose

Sickafoose added: “This is an especially fascinating phase for Pluto. Our work shows that the atmospheric pressure has just started to fall. I hope additional observations will help us confirm or rule out this pattern.” The findings appear in The Planetary Science Journal and were reported by Gizmodo.

Such observations are significant because they offer a real-world example of how a remote dwarf planet's atmosphere responds as its orbit takes it farther from the Sun. Understanding Pluto's changes could therefore shed light on atmospheric behavior across other icy dwarf worlds in the outer Solar System, and it raises new questions about whether life is possible on other bodies sharing similar conditions.

As Pluto's atmosphere continues to diminish, it's crucial to consider the geological changes occurring on its surface. Recent findings have revealed the first evidence of ice landslides on Pluto, indicating a dynamic and evolving environment. These developments may provide further insights into the implications of its atmospheric shifts and the planet's overall behavior in response to its distance from the Sun.