Images sent back by NASA’s New Horizons spacecraft last week reveal that pluto has blue atmospheric hazes and water ice
on its surface. Alan Stern, New Horizons principal investigator from Southwest Research Institute (SwRI) sounded ecstatic:
“Who would have expected a blue sky in the Kuiper Belt? It’s gorgeous.”
Scientists revealed that the blue light is because of particles called tholins. They themselves are likely to be grey or red, but the way they scatter, they radiate blue light.
“A blue sky often results from scattering of sunlight by very small particles. On Earth, those particles are very tiny nitrogen molecules. On Pluto, they appear to be larger — but still relatively small — soot-like particles we call tholins,” said science team researcher Carly Howett.
In a second significant finding, New Horizons has detected numerous small, exposed regions of water ice on Pluto.
The discovery was made from data collected by the Ralph spectral composition mapper on New Horizons. Science team member Jason Cook, of SwRI, said:
“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.”
But the team is still trying to understand why water appears exactly where it does, and not in other places.
Another curious aspect of the discovery is that the areas showing the most obvious water ice spectral signatures correspond to areas that are bright red.
“I’m surprised. We don’t yet understand the relationship between water ice and the reddish tholin colorants on Pluto’s surface,” says Silvia Protopapa, a science team member from the University of Maryland. The New Horizons spacecraft is currently 3.1 billion miles (5 billion kilometers) from Earth, with all systems healthy and operating normally. NASA had recently released images of Pluto’s close-up
. The high resolution images gave the world a unique glimpse of the icy dwarf planet at the very end of our solar system.