Pluto is as frigid as it gets, with almost zero temperatures. But it does have its own tropical zones, as discussed by scientists at the 47th Lunar and Planetary Sciences Conference in Houston, Texas.
The most distant familiar object in the solar system emerged in five recent papers in the journal Science as dynamic, its geological and geographical features constantly changing. But only less than half of data obtained from the Pluto flyby of the New Horizons spacecraft in July 2015 have been analyzed, which means space enthusiasts are in for more surprises from the dwarf planet.
Pluto, for instance, maintains a very dynamic climate that alters its atmosphere over time, potentially causing its surface to have liquid nitrogen lakes and rivers.
But since it spins on an axis like our own planet, it also has seasons at certain periods of the year, and therefore has its own arctic and tropical zones. Its tropical zones pertain to areas where the sun makes an appearance directly overhead.
New Horizons, in addition, seems to have captured the dwarf planet in between two extreme states. Pluto has a 120-degree tilt as well as a slow-oscillation pattern varying by 20 degrees, while Earth, in contrast, has a 23-degree axial tilt that causes alternating summers in the Northern and Southern Hemispheres and confined Arctic and Antarctic regions.
If Earth were like Pluto, explained MIT's Richard Binzel at the conference in Houston, it would be situated in the Arctic zone. In the distant heavenly body the slow growth of the tropics and the polar zones likely drove its own climate.
These changes, according to Alan Stern of Southwest Research Institute, may have resulted in atmospheric pressure changes, which are at times 100,000th of that on Earth. This could lead to where nitrogen exists in all three phases — solid, liquid, and gas — as attested to by New Horizons images showing what look like rivers and even glacial flow.
Mike Summers of George Mason University expanded on the "incredibly diverse" surface of Pluto.
"Pluto is geologically active! I doubt there's a single person on Earth who would have expected to see that," he writes, delving on some surface areas such as those heavily cratered from asteroid impacts, seeming to date back to just after Pluto's formation about 4.5 billion years ago.
Areas such as the Sputnik Planum, the planet's heart-shaped, Texas-sized ice glacier, exhibited no proof of asteroid impacts, suggesting uninterrupted surface activity including convection of ice from underground.
Pluto's diverse chemical compositions — such as the presence of different types of ice like nitrogen, methane, and carbon monoxide — also clue in on its geological climate. These ice reservoirs, added Summers, reflect long epochs of ice transport across Pluto's surface.
So much more is yet to come, as another 40 papers are on the way to be told, and huge bodies of information to be transmitted by the spacecraft to Earth.
