Based on information gathered by NASA´s New Horizons Spacecraft during its flyby over Pluto last year, scientists have been able to establish the depth and size of a layer of solid nitrogen ice in Pluto’s surface feature known as ¨The heart.¨ or Sputnik Planum. The findings demonstrate that despite the distance and coldness of the planet, there is sufficient energy to drive geological processes of convection.

Nitrogen ice in Sputnik Planum

New Horizon images revealed a vast area in Sputnik Planum involving principally nitrogen ice, which is divided into polygon shape cells hundreds of kilometers across and with bulged midpoints.

It´s believed that this region of nitrogen ice is repeatedly being renewed by convection and that the presence of the huge cells is mainly due to the overturning of a thick layer of solid nitrogen.

Process of convection

It´s believed that the ice cell patterns are produced by the slow thermal convection of nitrogen, when Pluto´s internal, although minimum, heat warms nitrogen, which causes it to rise in great smudges, like a lava lamp. The nitrogen cells then cool off and sink in an ongoing cycle. Although the convection process accounts for a few centimeters a year, the recycling process takes approximately 500,000 years.

New Horizons Spacecraft

New Horizons was launched on January 19, 2006 and performed a study of Pluto´s features and moons that went on for six months.

On July 14, 2015, the spacecraft got a close approach of Pluto and in the present, New Horizons is 34.74 astronomical units (AU) away from earth and 2.58 AU ahead of Pluto, heading into the Kuiper belt to explore a few more icy bodies and make new discoveries.

The mission

The objective of this mission is to understand the way in which ice dwarf planets, including Pluto icy surface and Kuiper Belt bodies have evolved over time.

By studying Pluto and its moons, new horizons will help understand in what category, either rocky planets or gas giants, they fit in, as Pluto and its largest moon, Charon have solid surfaces, like terrestrial planets, but unlike them, they also possess a thick layer of ice covering their surface.