Back in 2000, Alan Stern predicted that the New Horizons Probe would find “something wonderful”, and he was about right. As the NASA’s Horizons Spacecraft flies over Pluto, scientists have more questions than answers.

The mission probe discovered mountains, craters, recent glaciers, and took a look at Pluto’s atmosphere, which astronomers can’t explain yet, as it flied to the planet at more than 30,000 mph.

Alan Stern, a planetary scientist, and his research group are intrigued by the nature of Pluto’s icy surface, saying that the resurfacing process in the dwarf planet couldn’t be linked to tidal forces, as they aren’t a viable heat source for Pluto, or Charon —its large moon.

“For Pluto, the rugged mountains and undulating terrain in and around require geological processes to have deformed and disrupted Pluto’s water ice-rich bedrock,” researchers say in the paper, published in the journal Science.

Pluto Ralph surface imaging over the western side of Sputnik Planum. (A) Orthographic projection of the LORRI mosaic. (B) False-color Ralph image from three near-IR wavelengths. (C) LEISA (Linear Etalon Imaging Spectral Array) map of CO ice absorption. Credits: Sciencemag

Researchers question how this geological process could have happened, and where does the energy that caused it came from. Pluto’s bedrock, made of ice and frozen nitrogen, methane, and carbon dioxide, include mountains that reach up to 11,000 feet high.

New Horizons found widely distributed impact craters across the surface, and some of them “appear to be substantially degraded or infilled, and some are highlighted by bright ice-rich deposits on their rims and/or floors,” researchers wrote.

Scientists are amazed to find out that Pluto is geologically active, after noticing that the landscape has been resurfaced within the last 100 million years, a very little magnitude in geological time. “Finding that Pluto is geologically active after 4.5 billion years — there’s not big enough typeface to write that in. It’s unbelievable,” Stern said, according to Space.

When it comes to Pluto’s atmosphere, researchers found that the atmosphere is cooler than expected, showing low pressure measures. However, scientists remark they wouldn’t know for sure if this differences are due to calibration issues on the instruments. “Either they got it wrong, or the atmosphere is now collapsing. If so, it’s very sudden,” Stern said, according to National Geographic.

Also, scientists noticed different layers of haze in Pluto’s atmosphere. “What’s creating them? We don’t know,” says Stern. “We also see evidence of wind streaks on the surface, and what look like dune fields, which suggests that the atmosphere was substantially thicker in the past, more like the atmosphere of Mars,” Stern said.

Pluto color/panchromatic composite image. This is a composite of high-resolution panchromatic images and lower-resolution color images enhanced to show the diversity of surface units on Pluto. Credits: Sciencemag

Pluto’s moons

The New Horizons probe is also studying Charon, a 750-mile-wide satellite, as well as Nix, Hydra, Kerberos and Styx —considerable smaller moons, less than 35 miles across. Scientists report that this satellites reveal themselves as complex and varied worlds as well.

Charon also has an extensive cratered area, and its north polar region appears to be dark and reddish in color, due to the presence of organic residues resulting of the interaction between radiation or charged particles with nitrogen and methane.

The probe found a big, reddish crater on Nix, making scientists guess that it is dark beneath that icy surface. Information about Styx and Kerberos isn’t available yet —besides their size— which isn’t surprising taken into account that these moons were discovered in 2006, precisely by the New Horizons probe.

The origins of Pluto-Charon

Researchers believe they have enough information to draw one conclusion about the origins and evolution of the Pluto-Charon system:

“The New Horizons encounter with the Pluto system revealed a wide variety of geological activity — broadly taken to include glaciological and surface-atmosphere interactions as well as impact, tectonic, cryovolcanic, and mass-wasting processes on both the planet and its large satellite Charon,” the paper says.

Scientists suggest that other small planets of the Kuiper Belt could also express similarities on their developments like Pluto.

‘New Horizons’, new discoveries

The mission, that cost nearly $720 million, was launched in January 2006. This is the first time that the probe provides a Pluto’s close-up. On July 14, the spacecraft got near the planet by 7,800 miles, capturing images and data on the planet.

Stern and his team have been analyzing and interpreting this data for the past three months, providing information through conferences and press releases. This led to the integration of all this data in the paper, published in the Journal Science.

Stern and his team say that most part of the data still remains in the spacecraft, meaning that more answers —or questions— are waiting to be unveiled.

Source: Journal Science