New images released last week by NASA’s New Horizons spacecraft reveal that Pluto has blue skies — much like Earth’s — and parts of the surface are covered in red water ice.
According to NASA, the planet’s haze particles are actually likely to be more gray or red than actual blue, but the way the particles scatter the blue light has many researchers excited. The blue tint in the skies surrounding Pluto gives scientists an indication about the size and makeup of those particles. On Earth, the scattering of particles that give us our blue skies are very tiny nitrogen molecules, says Carly Howett of the Southwest Research Institute.
“On Pluto they appear to be larger — but still relatively small — soot-like particles we call tholins.”
Tholin particles, scientists believe, form high up in Pluto’s atmosphere, where nitrogen and methane molecules are then broken apart and ionized by ultraviolet sunlight. The ultraviolet sunlight also causes the molecules to react with one another, which then creates even more complex negatively and positively charged ions. When the broken molecules recombine, they form macromolecules, and from there, they continue to combine until they become very small particles. Volatile gases in the atmosphere then coat the surfaces of the tiny particles with ice frost before they fall through Pluto’s atmosphere to the planet’s surface, where they add to Pluto’s distinctive red coloring.
The macromolecules found in Pluto’s atmosphere that help cause the planet’s blue skies were first found to occur in the atmosphere of Saturn’s moon Titan, and while Titan itself isn’t lucky enough to have the beautiful blue skies that Pluto does, Saturn’s northern hemisphere does, while it’s southern hemisphere does not.
Alex Parker, the NASA scientist responsible for creating the algorithm that would find the true color image of Pluto, described the process on Twitter yesterday (October 8), and he also mentioned how the process itself managed to cause a glitch in his computer when it first discovered the blue haze.
He also shared with the world the first glimpse of Pluto with its striking blue haze.
The second major finding revealed by New Horizons’ photographs is that there appear to be many small, exposed regions of water ice on Pluto’s surface. This is especially significant, because it could mean that a liquid sea lay under Pluto’s surface, reports the Daily Mail. Jason Cook, a science team member also with the Southwest Research Institute, says that though they’ve always expected Pluto had water ice on its surface, it’s never been discovered until now.
“Large expanses of Pluto don’t show exposed water ice. because it’s apparently masked by other, more volatile ices across most of the planet. Understanding why water appears exactly where it does, and not in other places, is a challenge that we are digging into.”
One of the most interesting aspects of the discovery of water ice on Pluto’s surface is that each region that has areas covered in this water ice happen to correspond to areas on Pluto’s surface that are bright red in color in the most recently released images of the planet’s surface.
“I’m surprised that this water ice is so red,” says Silvia Protopapa, a science team member from the University of Maryland. “We don’t yet understand the relationship between water ice and the reddish tholin colorants on Pluto’s surface.”
Though many were hoping that the “big announcement” NASA had planned for Thursday would involve aliens, or at the very least, signs of life having been found on the distant planet, the actual revelation — that Pluto has blue skies much like Earth’s, as well as mysterious red ice on its surface of unknown origin — are still incredible findings on a planet that lies roughly 4.67 billion miles from Earth.
[Image Credit: NASA/APL/SwRI/Getty Images]