Pluto is just plain weird.
Eight months after the New Horizons spacecraft whizzed past this small planet, scientists have published a whole suite of studies that bring into perspective just how strange and wonderful a place the tiny dwarf planet is.
"These five detailed papers completely transform our view of Pluto – revealing the former 'astronomer's planet' to be a real world with diverse and active geology, exotic surface chemistry, a complex atmosphere, puzzling interaction with the sun and an intriguing system of small moons," Alan Stern, New Horizons principal investigator, said in a NASA statement about the new studies.
Here are the main takeaways detailed in the papers:
Pluto's surface is even more alien than we thought. The dwarf planet's smooth plains, scarred craters and ice mountains were not what scientists expected to find on something so far out in the outer solar system.
Scientists think all that diverse terrain means Pluto has been geologically active for much of its life over the past 4.6 billion years. Part of the surface diversity is caused by methane, nitrogen and carbon monoxide ices that melt and refreeze in a much more complicated cycle than scientists expected to find.
"We see variations in the distribution of Pluto's volatile ices that point to fascinating cycles of evaporation and condensation," Will Grundy, lead author on one of the papers, said in the NASA statement. "These cycles are a lot richer than those on Earth, where there's really only one material that condenses and evaporates – water. On Pluto, there are at least three materials, and while they interact in ways we don't yet fully understand, we definitely see their effects all across Pluto's surface."
Pluto's atmosphere is still a mystery. Turns out Pluto's atmosphere is about 70 degrees Fahrenheit colder and much more stable than scientists initially thought.
"The thought was that Pluto's atmosphere was escaping like a comet, but it is actually escaping at a rate much more like Earth's atmosphere," Fran Bagenal, lead author on one of the papers, said in a statement.
Previously, scientists thought nitrogen was escaping the atmosphere since most of Pluto is covered in nitrogen. But this new data surprised researchers and revealed that methane is the primary escaping gas.
We finally got a close look at Pluto's five moons. Scientists think that Pluto and its largest moon Charon once collided. Instead of completely breaking apart, they went into orbit around one another.
Now there's evidence that Pluto's four smaller moons may have formed from chunks of debris that spilled out of the same collision, according to the new research.
We still only have about half the data that New Horizons collected during its flyby, so Pluto may hold many more mysteries.
"This is why we explore," Curt Niebur, a New Horizons program scientist, said in a statement. "The many discoveries from New Horizons represent the best of humankind and inspire us to continue the journey of exploration to the solar system and beyond."