A team of scientists at Purdue University has developed a new theory to explain why Pluto’s moon, Charon, has a reddish north pole.
In their paper, published in Nature Communications, Stephanie Mentin, Michael Surrey and Ali Bramson describe their study of the reddish surfaces of several icy bodies in the Kuiper Belt, and how they might relate to the reddish Charon pole.
Previous research has shown that many icy bodies in the Kuiper Belt are partially or completely covered by a reddish-brown substance.
Previous research has also shown that the substance is a type of tholin, compounds that form when organic chemicals are exposed to radiation. But this raised the question of where the organic compounds came from. In this new effort, scientists hypothesized that it comes from methane emitted by ice volcanoes.
To test their theory, the researchers turned to Pluto’s moon, Charon, whose north pole is covered in tholene. They note that previous research suggests that gases escaping from Pluto are responsible for the reddish pole. But previous research also showed that the moon was covered in a liquid ocean that contained many substances, including methane.
The scientists noted that as the ocean froze, the methane had become trapped in the ice. They also noted that when the water becomes pressurized, fissures may form, leading to an accidental volcanic eruption.
The team suggests that such frozen volcanic eruptions may have released some methane. If some of this methane managed to drift to the North Pole, it would freeze and fall to the surface. Had it fallen to the surface, it would have been exposed to millions of years of sunlight, causing it to turn red.
The scientists created simulations of methane particles circulating in Charon’s atmosphere, calculating how much methane would escape under such a scenario and how much would have made it to the North Pole. They found that approximately 1,000 billion metric tons of gas could reach the North Pole, more than enough to create a red cap.
Source: phys.org
