The 21st century saw the exit of Pluto from its designation as one of the planets of the solar system back in 2006. Interestingly, however, the narrative continues, with scientists continuing to produce studies looking at theories behind the ways it formed, with others contesting Pluto's status and arguing that it should be reinstated as a planet!
As the debate rages on--one which, by all indications will not end any time soon--astronomers are focusing their efforts on setting up a good amount of knowledge of the distant dwarf planet. A recent study suggests that certain landscape features point to evidence ancient glaciers played a role in its formation.
Evidence in the Ridges
The research team looked at terrains around the Sputnik Planitia, a group of nitrogen-filled basins. Images were provided of the area thanks to the efforts of scientists behind the New Horizons Mission, and researchers believe that the nitrogen-filled basins are the source of all shifts to Pluto's crust which have occurred over time. Researchers found two distinct types of terrains around the northwestern edge of the Sputnik Planitia, which they described as "fluted" and "washboard".
The methods of analysis chosen was morphometry, which involved looking at the external dimensions and shape of the ridges and landforms of the area. After comparing the terrains to sublimation pits--surface depressions that form when ice is converted to gas with the help of sunlight--from the southwest region, they concluded that they formed from receded glacial ice which "formed and disappeared early in Pluto’s history, soon after the formation of the Sputnik Planitia basin."
How early in history was this? According to (SETI) scientist Oliver White, who wrote the letter making the claim about the terrain: roughly 4 billion years ago. And to put the massive scale of the ridges into perspective, White explains, "The dense spacing of the ridges allows us to precisely map out the past coverage of the glaciation that deposited them, which extended across at least 70,000 km2 of Pluto’s uplands (larger than the state of West Virginia)”.
The Picture Behind Pluto's Origins Becomes Clearer
Another study released this year which deepens our understanding of how Pluto came to be involved the discovery of icy dunes that point to a more dynamic formation of the dwarf planet than scientists ever thought possible.
Jeffery Moore, a research scientist at NASA’s Ames Research Center in Silicon Valley, concluding about their work: “More research will help us pin down their origin,” he said, adding, “Whatever they are, it’s clear Pluto is one of the most amazing and complex objects in our solar system.”
All the evidence presented this year indicates one simple truth: there is still much unknown about Pluto. As previously stated, although its status as a planet remains up in the air, for now, it is important that we continue to evolve a body of information that contributes to collective understanding about its origins.
Details about the study appear in a paper, titled "Washboard and fluted terrains on Pluto as evidence for ancient glaciation", which was published November 12th in the Nature Astronomy journal.