The Problem with Pluto

Despite being perhaps the most popular non-Earth planet, Pluto has presented more than its fair share of problems to the scientific community. The recent New Horizon’s probe’s trip to the former planet (which is still sending back data, slowly but surely) only raised new questions.“It’s going to send a lot of scientists back to the drawing boards,” New Horizon’s project leader Alan Stern said, according to Science Magazine.

Here are the facts, as relayed by NASA and the New Horizons team:

• Pluto doesn’t have nearly the amount of asteroid impacts that NASA had predicted. In fact, the surface of Pluto is fairly smooth.
• The surface of Pluto’s largest moon, Charon, is even smoother than Pluto’s. This is despite there being no shortage of debris to run into in that part of the solar system.
• At least some of the ice on the surface of Pluto appears to be moving in rivers, much like glacial ice does on Earth. The problem with this is that Pluto’s ice is substantially colder than the coldest ice on earth, and shouldn’t be able to move. One possible explanation to this last point would be if the ice were formed from frozen methane, nitrogen, or other lower-freezing point chemicals. However, this would raise new questions about how this methane ice is replenished and doesn’t just evaporate off into space.

The part that most perplexes NASA is how these three points mesh with the proposed age for the solar system (and for Pluto) of 4.5 billion years.

Now, while I personally see this as evidence of a much younger solar system, there are also several other theories being floated by scientists that could possibly also explain this phenomenon. The most popular of which seems to be that Pluto is somehow geologically active. This explanation holds that Pluto was getting bombarded by space debris, but that an active surface has since smoothed the face of the planet out. The same would hold true for Charon.

It’s not unheard of for a non-Earth planetary body to have volcanos. Jupiter’s moon Io is extremely volcanically active. As of yet, though, there is no evidence of active volcanos on Pluto (although we did only get a glimpse of the distant Planet), and Pluto is a good deal further out in the solar system than Io is.

In the coming months, the New Horizons team will keep releasing data taken by the probe during its quick flyby. Unfortunately, this data can only be transmitted back to Earth very slowly. NASA predicted that it will take about a year before we get all the data back. Perhaps some of that data will shed more light on the questions surrounding Pluto’s baby-faced surface, or maybe it will just continue to be one of the unsolved mysteries of the universe.