NASA Unveils Pluto's Blue Sky And Water Ice

NASA has unveiled a stunning image showing off Pluto's blue sky.

Yes, that's right a blue sky in the Kuiper Belt.

“Who would have expected a blue sky in the Kuiper Belt? It’s gorgeous,” said Alan Stern, New Horizons principal investigator.

Stern sent the rumour mill into over driver ahead of NASA's announcement when he made a speech on Monday at the University of Alberta in Canada.

Speaking to a packed university hall he said ""This world is alive...Nasa won’t let me tell you what we’re going to tell you on Thursday. It’s amazing."

The highly-anticipated news, which NASA was unusually tight-lipped about, includes first colour images of Pluto’s atmospheric hazes. No aliens.

What has caught the attention of the New Horizons team is the way the haze scatters blue light.

“A blue sky often results from scattering of sunlight by very small particles," said science team researcher Carly Howett.

"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.”

NASA also announced the presence of water ice on Pluto -- a finding the space agency has described as "significant."

Now the challenge for the New Horizons teams is find out why water ice appears where it does on Pluto.

"Large expanses of Pluto don’t show exposed water ice,” said science team member Jason Cook.

This is “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.”