Pluto's "Earth-Like Characteristics" Are More Diverse Than Expected

Good for Pluto.

Pluto has had a tough few years since losing its planet status. In the years since its demotion, NASA scientists found the trans-Neptunian object to be a colder, hazier hellscape than once believed, and other researchers are actively searching for Pluto’s replacement in the elusive Planet Nine. It’s about time Pluto got some good news.

According to a new study published in the journal Science on Thursday, the surface of Pluto is more geologically diverse and dynamic than had been expected. One surprising find is that Pluto has dunes that give the demoted dwarf planet “Earth-like characteristics” rarely seen elsewhere in the Solar System. Outside of Earth, dunes only exist on Mars, Venus, Saturn’s moon Titan, and, somewhat randomly, Comet 67P.

Led by Matt W. Telfer, Ph.D., of the University of Plymouth, and the team first identified Pluto’s dunes from images taken by the New Horizons spacecraft. Unlike the sandy hills found on Earth, Pluto’s dunes are made from solid methane ice grains, found on the dwarf planet’s mountainous Sputnik Planitia region.

Dunes (black lines) at the margins of western Sputnik Planitia. Prominent wind streaks are marked with orange lines.

Matt W. Telfer/Science

“When we first saw the New Horizons images, we thought instantly that these were dunes but it was really surprising because we know there is not much of an atmosphere,” said Jani Radebaugh, Ph.D. and co-author from Brigham Young University. “However despite being 30 times further away from the sun as the Earth, it turns out Pluto still has Earth-like characteristics. We have been focusing on what’s close to us, but there’s a wealth of information in the distant reaches of the solar system too.”

While Pluto’s dunes, situated at the edges of mountains near visible wind streaks, certainly give off an Earthly vibe, the dwarf planet’s atmosphere is considered too thin to actually pick up the tiny grains of methane to form these dunes. Dunes normally require a lot of wind-power to form, and it’s still unclear how Pluto’s methane dunes got there. Telfer’s team posits that methane grains could have been sent into the atmosphere due to the melting of nitrogen ice, or blown down from nearby mountains in Sputnik Planitia.

The age of Pluto’s dunes is also forcing researchers to reconsider what is known about the shamed former-planet. As observed by Telfer and Radebaugh’s team, these methane dunes appear largely undisturbed, which suggests that they were formed within the past 500,000 years or earlier. If they have, indeed, formed in the recent geological past, it would mean that Pluto, at 4.5 billion years old, still hosts an active and changing atmosphere that produces geologically young landforms.

While Earth-like characteristics might not bring back Pluto’s planet status, the rarity of this find means the dwarf planet still has a lot of insight to offer scientists. This discovery means researchers now must rethink the role of a space object’s atmosphere in shaping the surface landscape.