Pluto's planetary status might continually be in flux, but researchers recently discovered something far more interesting than being a planet or not. Pluto could be a gigantic comet at its core.
A team from the Southwest Research Institute developed a novel theory about its origins. They used data about the Sputnik Planitia -- a nitrogen-ice glacier that makes up the left half of Pluto's "heart."
"We found an intriguing consistency between the estimated amount of nitrogen inside the glacier and the amount that would be expected if Pluto was formed by the agglomeration of roughly a billion comets or other Kuiper Belt objects similar in chemical composition to 67P, the comet explored by Rosetta," Chris Glein, a scientist at the Southwest Research Institute (SwRI) in San Antonio, said in a statement.
The European Space Agency's now-finished Rosetta mission orbited in the Comet 67P/Churyumov-Gerasimenko area from 2014 to 2016. The mothership also dropped the lander Philae onto the icy surface. Philae became the first soft touchdown on the surface of a comet.
The data collected during Rosetta and with NASA's New Horizons mission from July 2015 gave Glein and SwRI researcher Hunter Waite enough information to theorize the new Pluto formation.
The SwRI team isn't stopping at just that theory, however. In addition to the comet creation model, the team is also looking into a solar model. In the solar model, Pluto would have formed from cold ices that give the Dwarf Planet a chemical composition that would be closer to that of our Sun.
"Our research suggests that Pluto's initial chemical makeup, inherited from cometary building blocks, was chemically modified by liquid water, perhaps even in a subsurface ocean," Glein said.
"This research builds upon the fantastic successes of the New Horizons and Rosetta missions to expand our understanding of the origin and evolution of Pluto," Glein said.
"Using chemistry as a detective's tool, we are able to trace certain features we see on Pluto today to formation processes from long ago," he added in his statement. "This leads to a new appreciation of the richness of Pluto's 'life story,' which we are only starting to grasp."
The Rosetta mission ended in a spectacular fashion in September 2016. The probe's handlers guided it to intentionally crash on the surface of 67P. New Horizon still has more work to continue. The craft will do a flyby of a small Kuiper Belt object known as 2014 MU69 -- or Ultima Thule -- on January 1, 2019. That flyby will be approximately 1 billion miles farther than Pluto's orbit and will hopefully give researchers a discovery just as groundbreaking as this one. That flyby will also be the main feature of the New Horizon's extended mission.
The study from the Southwest Research Institute was published in a recent edition of the online journal Icarus.