Scientists have also picked out a dark spot about 6 miles wide, on a surface that in all somewhere between Charon and Pluto in terms of brightness. Given the commonplace nature of asteroid and comet impacts throughout the solar system and the presumed age of Pluto – more than 4 billion years – the lack of craters suggests that it must be geologically active.

The close-up image of an equatorial region near the base of Pluto’s bright heart-shaped feature shows the mountain range, a discovery that means Pluto may still be geologically active today.

One close-up image depicting an area near Pluto’s equator shows a mountain range that rises as high as 11,000 feet above the dwarf planet’s icy surface, Fox News reported.

Pluto is, on first blush, unlike any single world yet seen in the solar system.

Scientists still aren’t sure how those characteristics might have been formed.

The scientists also revealed new photos of some of Pluto’s moons, Hydra and Charon.

And Pluto, long considered the farthest planet from the Sun before it was reclassified as a dwarf planet in 2006, has never before been explored. Scientists said the data for the first time show the size of the irregularly shaped moon, 43 by 33 kilometres across, and that it is probably coated with frozen water.

Twenty four hours after the successful flyby of Pluto, New Horizons achieved another milestone with the piano-sized Nasa spacecraft discovering icy mountains on the planet.

The mission was a complete success, with New Horizons successfully avoiding debris, which the scientists thought offered a one in 10,000 chance of jeopardising the mission.

In all, nine small mementos were tucked aboard New Horizons.

Not wanting to feel left out, New Horizons was able to capture some rough images of Pluto’s other smaller moons: Hydra, Nix, Styx and Kerberos, with the first revealing that it’s 43km by 33km. Instead of the moon orbiting around the dwarf planet, Charon and Pluto orbit around a center of gravity between the two bodies.

The spacecraft flew within 7,767 miles of Pluto, sending long-awaited images back to an anxious audience on Earth.

The images released Wednesday have a resolution of about 100 meters (yards) per pixel.

John M. Grunsfeld, Nasa Associate Administrator for the Science Mission Directorate, speaks at the Johns Hopkins University Applied Physics Laboratory on Tuesday in Laurel, Maryland.