New Horizons continues to send back extraordinary images from Pluto.
“Who would have expected a blue sky in the Kuiper Belt? It’s gorgeous,” said Alan Stern, New Horizons principal investigator from Southwest Research Institute (SwRI), Boulder, Colorado.
The haze particles themselves are most likely grey or red, but the way they scatter blue light has caught everyone’s attention.
“That striking blue tint tells us about the size and composition of the haze particles,” said science team researcher Carly Howett, also of SwRI. “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.”
New Horizons has also detected small, exposed regions of water ice on Pluto.
“Large expanses of Pluto don’t show exposed water ice,” said science team member Jason Cook, of SwRI, “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.”
The new images come just weeks after New Horizons sent back some particularly mystifying images.