Nasa's New Horizons Spots Methane on Pluto's Snowcapped Peaks

The New Horizons team has discovered a chain of exotic snowcapped mountains stretching across the dark expanse on Pluto, informally named "Cthulhu Regio", that has methane - an important trace gas in Earth's atmosphere.

The new images reveal a mountain range located in southeast Cthulhu that is 420 km long. The range is situated among craters, with narrow valleys separating its peaks.

The upper slopes of the highest peaks are coated with a bright material that contrasts sharply with the dark red color of the surrounding plains.

Scientists think this bright material could be predominantly methane that has condensed as ice onto the peaks from Pluto's atmosphere.

"That this material coats only the upper slopes of the peaks suggests methane ice may act like water in Earth's atmosphere, condensing as frost at high altitude," said John Stansberry, New Horizons science team member from Space Telescope Science Institute, Baltimore, Maryland.

The data indicates that the location of the bright ice on the mountain peaks correlates almost exactly with the distribution of methane ice.

One of Pluto's most identifiable features, Cthulhu stretches nearly halfway around Pluto's equator, starting from the west of the great nitrogen ice plains known as Sputnik Planum.

Measuring approximately 3,000 km long and 750 km wide, Cthulhu is a bit larger than the state of Alaska.

Cthulhu's appearance is characterized by a dark surface, which scientists think is due to being covered by a layer of dark tholins - complex molecules that form when methane is exposed to sunlight.

Cthulhu's geology exhibits a wide variety of landscapes - from mountainous to smooth, and to heavily cratered and fractured.

The new image was obtained by New Horizons at a range of approximately 33,900 km from Pluto, about 45 minutes before the spacecraft's closest approach to Pluto on July 14, 2015.