Photos of Pluto from New Horizons spacecraft wow scientists

New photos released by NASA show mountains, possible dunes, and several layers of haze on the dwarf planet Pluto. The images were sent by the New Horizons spacecraft as it swept past the distant planet.

According to scientists, the photos show more diverse landscape than what had been earlier imagined.

"If an artist had painted this Pluto before our flyby, I probably would have called it over the top - but that's what is actually there," said Alan Stern, New Horizons' principal scientist from Southwest Research Institute in Boulder, Colorado.

One picture shows dark ancient craters bordering much younger icy plains and also visible dark ridges that, according to scientists. might be dunes.

According to one outer solar system geologist, William McKinnon of Washington University in St Louis, it would be 'completely wild' if the ridges were dunes considering Pluto's thin atmosphere.

"Either Pluto had a thicker atmosphere in the past, or some process we haven't figured out is at work. It's a head-scratcher,' he said.

In addition to geologic features, the images show there may be several layers to the atmospheric haze surrounding Pluto.

Also thanks to the haze, which created a twilight effect, the spacecraft could see places on the night side that scientists never expected to see.

''Pluto is showing us a diversity of landforms and complexity of processes that rival anything we've seen in the solar system,'' said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute (SwRI), Boulder, Colorado.''

Sarah Dodson-Robinson, assistant professor, in the Department of Physics and Astronomy at the University of Delaware, ''The surface of Pluto is defined by interesting large-scale structures. A black feature near the equator has already been dubbed the ''whale,'' while there is what appears to be a white heart next to the whale. The white probably indicates ice. It's not clear why Pluto's surface should have such compositional variations.''

John Gizis professor in the in the Department of Physics and Astronomy at the University of Delaware, said ''The initial images show that Pluto has a very complex surface showing the influence of geological and atmospheric processes. The mission has also confirmed that Pluto is the largest dwarf planet in the Kuiper Belt in terms of its size, although Eris is actually more massive.''

A new close-up image of Pluto received from NASA's New Horizons spacecraft last month revealed a vast, crater-less plain that appears to be no more than 100 million years old, and is possibly still being shaped by geologic processes, say scientists. (See: NASA's New Horizons finds plains in Pluto's 'heart-shaped feature).

(Read NASA report:  New Pluto Images from NASA's New Horizons: It's Complicated)