After NASA’s New Horizons spacecraft made its nearest approach to Pluto in early July—a trip that lasted nine years and three billion miles—much information is still arriving about the solar system’s most well-known dwarf planet. The craft passed close enough to take the clearest-yet images of the distant planet and its five moons, which have given astronomers a new perspective of its properties.

New Horizons was launched in January 2006 by NASA after over a decade of attempts to construct a craft that could reach Pluto. Members of the Applied Physics Laboratory of John Hopkins University in Maryland, who built the spacecraft and managed the mission, broke out in cheers as the first images from the flyby arrived to Earth.

Contrary to the expectation that Pluto is covered with craters, the images have revealed large areas of flat surface: “…some areas of the planet were as smooth as a billiard ball and others rumpled and rippled; some stained the color of dried blood and others gleaming bright white,” Futurity, a publication which compiles research news from top universities, reported.

According to scientists, this could imply geological activity on the planet since “…craters are the scars of old impacts, and if a planet’s face is heavily scarred, it means there is no active geological process to renew and sculpture the planet’s surface. Many craters would mean Pluto was dead and, like most dead things, boring.”

Astronomers noted that for a planet to have smooth surfaces, it must have an internal heat source.

“Where this heat comes from is a mystery,” The Guardian stated. “Pluto is thought to be too small to generate much radioactive heat, nor is it squeezed by a larger world to generate tidal energy…Yet something is making it geologically active. This is the biggest mystery of the flyby. Resolving it promises to tell us something totally unexpected about planetary geology.”

As information pours in from New Horizons, which could take up to 16 months to download, astronomers expect to learn more about the solar system’s most mysterious planet.

An opinion piece in Deseret News noted, “Of course, this new information will likely do little to affect the day-to-day life of those of us stuck here on Planet Earth. But it will provide a point of inspiration to remind us that we are a small part of a wider universe, and there is still much to discover and explore.”