Destination Red / Pluto’s Partly Cloudy Skies

A small red-hued asteroid in the remote and freezing Kuiper Belt beyond Neptune is the next flyby target for the New Horizons Mission. Astronomers recently discovered it's redder than Pluto. This is an artist's impress of the Jan. 2019 flyby. Credit: Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Steve Gribben
A small, reddish asteroid in the remote and freezing Kuiper Belt beyond Neptune is the next flyby target for the New Horizons Mission. Astronomers recently discovered it’s redder than Pluto. This is an artist’s impression of the Jan. 2019 flyby. Credit: Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Steve Gribben

Red it is! NASA’s New Horizons mission, which flew past Pluto last July, is on its way to another asteroid that bears a colorful resemblance to the dwarf planet.

Observations made with the Hubble Space Telescope suggest that 2014 MU69, a small icy asteroid in the Kuiper Belt about a billion miles (1.6 billion km) beyond Pluto, is as red, if not redder, than Pluto. Of course, Pluto isn’t actually red the way we think of red. It’s more pink or brown, colors caused when hydrocarbon molecules such as methane in its atmosphere react with the ultraviolet part of sunlight to create more complex molecules called tholins that have a reddish-brown appearance. These drift down to the surface and “paint” the surface red.

Path of NASA's New Horizons spacecraft toward its next potential target, the Kuiper Belt object 2014 MU69, nicknamed "PT1" (for "Potential Target 1") by the New Horizons team. Although NASA has selected 2014 MU69 as the target, as part of its normal review process the agency will conduct a detailed assessment before officially approving the mission extension to conduct additional science. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker)
Path of NASA’s New Horizons spacecraft toward its next potential target, the Kuiper Belt object 2014 MU69, nicknamed “PT1” (for “Potential Target 1”) by the New Horizons team. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker

What’s exciting about the news is that this is our first hint of the surface properties of this remote object which New Horizons will survey during a flyby on Jan. 1, 2019. We are only beginning to know this new target, estimated at 27 miles (45 km) across, and so far away that it orbits the sun once every 293 years.

In other Pluto news, the New Horizons mission team has spied a handful of potential clouds in images taken with probe’s cameras. “If there are clouds, it would mean the weather on Pluto is even more complex than we imagined,” said Alan Stern, principal investigator for the mission.

Pluto's present, hazy atmosphere is almost entirely free of clouds, though scientists from NASA's New Horizons mission have identified some cloud candidates after examining images taken by the New Horizons Long Range Reconnaissance Imager and Multispectral Visible Imaging Camera, during the spacecraft's July 2015 flight through the Pluto system. All are low-lying, isolated small features-no broad cloud decks or fields - and while none of the features can be confirmed with stereo imaging, scientists say they are suggestive of possible, rare condensation clouds. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Scientists from the New Horizon mission have identified several possible cloud candidates after examining images taken by the spacecraft during its July 2015 flight through the Pluto system. All are low-lying, isolated small features-no broad cloud decks or fields . While none of the features can be confirmed, scientists say they are suggestive of possible, rare condensation clouds.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Scientists already knew from telescope observations that Pluto’s icy surface below that atmosphere varied widely in brightness. Data from the flyby not only confirms that, it also shows the brightest areas (such as sections of Pluto’s large heart-shaped region) are among the most reflective in the solar system. And brightness, which equals freshness, indicates surface activity.

Scientists from NASA's New Horizons mission have spotted signs of long run-out landslides on Pluto's largest moon, Charon. This image of Charon's informally named "Serenity Chasma" was taken by New Horizons' Long Range Reconnaissance Imager (LORRI) on July 14, 2015, from a distance of 48,912 miles (78,717 kilometers). Arrows in the annotated figure mark indications of landslide activity. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Scientists from NASA’s New Horizons mission have spotted signs of long run-out landslides on Pluto’s largest moon, Charon. This photo shows the informally named “Serenity Chasma”. Arrows mark possible landslides. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

While Pluto shows many kinds of activity, one surface process apparently missing is landslides. Surprisingly, though, they’ve been spotted on Pluto’s largest moon, Charon, itself some 750 miles (1,200 km) across. “We’ve seen similar landslides on other rocky and icy planets, such as Mars and Saturn’s moon Iapetus, but these are the first landslides we’ve seen this far from the sun,” said Ross Beyer, a science team researcher from Sagan Center at the SETI Institute and NASA Ames Research Center, Moffett Field, California.

Once again, being small, bitter cold and far from the sun doesn’t preclude more activity that anyone could have expected.