Ice Geysers Found on Charon

Quick, think of all the moons in the Solar System that have water ice welling up from within their cores. Sure, there's Enceladus, and I reported recently about Dione and Tethys. Europa's an easy one to remember. But did you ever consider Pluto's icy moon Charon?

Well, astronomers have found ice geysers there too.

According to a new press release from the Gemini Observatory, located atop Mauna Kea, Hawaii, there's strong evidence that Charon is continuously being coated by a thin layer of ammonia hydrates and water ice, welling up from inside the moon.

The discoverers think that there's some process going on inside the moon, mixing together ammonia and water, and then pushing it out onto the surface of Charon. These ice geysers seep out in a matter of days, or even hours, spreading this mixture out. It's happening so quickly that scientists anticipate that the entire surface of Charon is coated to a depth of 1 millimeter every 100,000 years.

Here's some detail about Charon's surface from Jason Cook, a PhD student at Arizona State University:

"Charon’s surface is almost entirely water ice. So it must have a vast amount of water under the surface, and much of that should be frozen as well. Only deep inside Charon could water be a liquid.
Yet, there is fresh ice on the surface, meaning that some liquid water must somehow reach the surface. The ammonia sitting on the surface provides the clue. It’s the ammonia that helps keep some material liquid. It makes it all feasible. Without ammonia the water could not get out there."

Astronomers will get a much closer look in a decade or so, when NASA's New Horizons spacecraft arrives on the scene to gather images of Pluto and Charon.
It will pass very close to the surface, and should be able to gather data about this process up close.

New Horizons will probably also be targeted to swing past other Kuiper
Belt Objects, so it'll see if this process is happening everywhere.

Original Source: Gemini Telescope News Release