Pluto is Nice, but it’s Losing its Atmosphere

The thin blue atmosphere of Pluto could be completely frozen by the year 2030, new studies of the dwarf planet reveal. Observations of star occultations as Pluto passes in front of background stars have now shed new light on the nature of the atmosphere surrounding this distant world.

Pluto is the smallest, most distant, and coldest object in the solar system known to possess an atmosphere. This thin layer of nitrogen gas (with traces of methane and carbon monoxide) periodically freezes before reforming as gas as the tiny world makes its way around the Sun.

The atmosphere of Pluto, as seen from its far side by the New Horizons spacecraft. This color is similar to what the human eye would see from the same position in space. Image credit: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute

“The atmospheric pressure has tripled over the past three decades, but as the dwarf planet orbits, our modeling showed that most of the atmosphere would condense out [until there is] almost nothing left. What our predictions show is that by 2030 the atmosphere is going to frost out and vanish around the whole planet,” explained Dr. Andrew Cole of the University of Tasmania.

Down in Front!

Stellar occultation takes place when a body (such as Pluto) passes in front of a star as seen from Earth. By studying the starlight passing through the atmosphere of Pluto, astronomers are able to gain insights into the density, temperature, and composition of the gasses surrounding the dwarf planet.