Have we discovered fuel on Pluto?S

One lure of space travel is the possibility that we might find a source of energy on another world. Now, a study published this month in The Astronomical Journal suggests that remote, frozen planetoid Pluto may harbor complex hydrocarbons like ethane and butane that are used as fuel here on Earth. These hydrocarbons, if confirmed, would also help explain the reddish-brown color we've seen on Pluto's surface.

Art by Ron Miller.

When the discovery was announced earlier this week, many called these possible hydrocarbons the "building blocks of life." We spoke to the lead author of the study, Southwest Research Institute scientist Alan Stern, who scoffed at this idea. "Let's be clear. This has nothing to do with the possibility of life on Pluto," he said today. "If I told a group of scientists that I'd found life based on this evidence, I would be laughed out of the room."

But that doesn't mean his group's discovery won't be important for future explorers. Explained Stern:

What we found is evidence for complex hydrocarbons. We have spent 40 years looking for hydrocarbons on Mars, and never found them. Then we look in the remotest part of the solar system, and here they are! We're not sure what kinds of hydrocarbons they are yet, but they aren't central to biology. We use them for fuel.

He added that it's long been known that the simplest form of hydrocarbon, methane, exists on Pluto. But he and his team now have evidence of more complex hydrocarbons, such as ethane or propane, gleaned from observations taken by the Cosmic Origins Spectrograph on NASA's Hubble telescope. There's also a possibility these aren't hydrocarbons at all, but organic compounds called nitriles.

Have we discovered fuel on Pluto?S

The presence of complex hydrocarbons would, however, explain Pluto's unusual color. "When you make heavier hydrocarbons in the lab, they're brownish red," Stern said. "We've never found a material on Pluto that could explain that. Mostly it's just frozen nitrogen, which is pure white like snow or water ice."

Though this could mean we'll be setting up mines on Pluto in the distant future, Stern cautions that we shouldn't expect to find life there based on the evidence he's seen. "This points towards an interaction of radiation from the sun or another source with the surface materials on Pluto in a mundane process that makes hydrocarbons," he asserted. "It's almost certainly not biology."

Read Stern and his colleagues' paper about complex hydrocarbons on Pluto in in The Astronomical Journal.