New Horizons Discovers Ice Mountains on Pluto

Mountains on Pluto (Credit: NASA-JHUAPL-SwRI)
Mountains on Pluto (Credit: NASA-JHUAPL-SwRI)

LAUREL, Md. (NASA PR) — New close-up images of a region near Pluto’s equator reveal a giant surprise: a range of youthful mountains rising as high as 11,000 feet (3,500 meters) above the surface of the icy body.

The mountains likely formed no more than 100 million years ago — mere youngsters relative to the 4.56-billion-year age of the solar system — and may still be in the process of building, says Jeff Moore of New Horizons’ Geology, Geophysics and Imaging Team (GGI). That suggests the close-up region, which covers less than one percent of Pluto’s surface, may still be geologically active today.

Moore and his colleagues base the youthful age estimate on the lack of craters in this scene. Like the rest of Pluto, this region would presumably have been pummeled by space debris for billions of years and would have once been heavily cratered — unless recent activity had given the region a facelift, erasing those pockmarks.

“This is one of the youngest surfaces we’ve ever seen in the solar system,” says Moore.

Unlike the icy moons of giant planets, Pluto cannot be heated by gravitational interactions with a much larger planetary body. Some other process must be generating the mountainous landscape.

“This may cause us to rethink what powers geological activity on many other icy worlds,” says GGI deputy team leader John Spencer of the Southwest Research Institute in Boulder, Colo.

The mountains are probably composed of Pluto’s water-ice “bedrock.”

Although methane and nitrogen ice covers much of the surface of Pluto, these materials are not strong enough to build the mountains. Instead, a stiffer material, most likely water-ice, created the peaks. “At Pluto’s temperatures, water-ice behaves more like rock,” said deputy GGI lead Bill McKinnon of Washington University, St. Louis.

The close-up image was taken about 1.5 hours before New Horizons closest approach to Pluto, when the craft was 478,000 miles (770,000 kilometers) from the surface of the planet. The image easily resolves structures smaller than a mile across.

  • Bill Rosenberg

    If New Horizons is traveling about 30,000 miles per hour, and was 1.5 hours away from it’s closest approach of about 7,800 miles, would it have been 478,000 miles away at the time of this photo? 🙂

  • DTARS

    This is “cool” as hell!
    Is it even possible for a human in a spacesuit to survive such temperatures???

  • Hug Doug

    My guess is that a spacesuit would need a heating rather than a cooling system, but otherwise yes.

  • Bulldog

    It will be very interesting to hear what the planetary geologists hypothesize. Is there active geology that explains the sharp ridges and lack of recent impact features or is there a low density of impactors at that distance from the Sun? In any event, very exciting find!

  • DTARS

    Wouldn’t it need to be built of special materials? Would fabrics bend? Would normal, void based insulation be able to insulate enough.

    Seems water ice would likely be a construction material for buildings and bridges.
    Foam insulate your ice cave. 🙂

  • Kirk

    The caption on the image at the APL site has half corrected it. It now shows “47,800 miles” but still follows that with “(770,000 kilometers)”.

    http://pluto.jhuapl.edu/Multimedia/Science-Photos/image.php?gallery_id=2&image_id=228

  • Jacob Samorodin

    I posted years ago on another website about the realization that there (will be/was) active geology on Pluto due to the fact that tidal flexing is/was working in the crust of Pluto during periods of Pluto’s orbit when Pluto regularly aligns with Charon and the Sun every 3.2 days. Such slow weak tidal stretching and flexing won’t generate much heat energy, but enough to warm nitrogen and methane ice to sublimation or at least slushiness.
    .

  • DTARS

    If started a supply train to Pluto and back you could launch every earth year right?

  • Geoff T

    Before you get too far ahead of yourself probably the biggest question to ask is how the heck you would land! Pluto has an almost negligible gravity well, an even more negligible atmosphere (no aerobraking) and the velocities required to get there are extreme. Unless you’re planning to lithobrake you don’t have many options except a flyby every few decades!

  • therealdmt

    “It will be very interesting to hear what the planetary geophysicists hypothesize. Is there active geology that explains the sharp ridges and lack of recent impact features or is there a low density of impactors at that distance from the Sun?”

    Interesting thought. The closest thing we’ve looked at at near that distance from the sun is the Neptune system, which might give some basis for comparison. Interestingly, Neptune’s largest moon Triton (which is roughly Pluto-sized and likely a captured Kuiper Belt Object what with its retrograde orbit and extreme axial tilt and all) also has a smooth young surface. The other, much smaller moons are a bit hard to make out in the pics from the Voyager flyby, but they look liked they might be pretty beat up (pockmarked).

    In the picture below Triton doesn’t look smooth, but that section is rough from what they call “cantaloupe skin”, not cratering. Voyager actually caught pics of active volcanos as it whizzed by, so Triton must be very geologically active indeed.

  • Snofru Chufu

    Pluto’s gravity is small (about 0.06 g), but not negligible. It results in an escape velocity of 1.2 km/s.

  • therealdmt

    Oh yeah, the other thing is climate. Alan Stern was talking about, in the Flyby Morning briefing, that the smoothness may be due to ‘climatological reasons’. I think, specifically, snow was what he was getting at.

  • mzungu

    100 million years without a single impact crater?

    How exactly do you determine the age and probability of collisions, when we don’t even have an idea of how many of them crater causing small Kuiper belt object are out there? Impact probabilities out there are likely to be a totally different ball game out there than the inner systems with massive gravity well that these guys used to play with…

  • Kirk

    And they have now fully corrected it to “47,800 miles (77,000 kilometers)”.

  • Vladislaw

    You would not land as much as ‘dock’ with the body.

  • Snofru Chufu

    Before you can “dock” to Pluto as you propose (:-), you was already accelerated by Pluto to a speed of 1.2 km/s in direction of his surface.

  • Hug Doug

    Actually, getting to orbit around Pluto is well within our technological capabilities today. Assume a Dawn-like ion engine spacecraft, assume a New Horizons-like gravitational assist from Jupiter, then a flip around and run the ion engines to slow down after that.

    NH was the fastest thing we’ve ever launched off of Earth, and it took just a year to get to Jupiter. After the gravitational assist there it was going 23 km/s, however, factor in gravity losses to the Sun on the outbound journey, and NH flew by Pluto at 13.78 km/s.

    Pluto’s orbital speed is 4.7 km/s, so the probe still needs to slow down (based on NH-like gravity assist from Jupiter) by 9.8 km/s to be able to enter orbit around Pluto. This is within the capabilities of Dawn’s ion engine system.

    So all that’s needed for a lander are rocket engines that can handle the relatively small dV of 1.2 km/s. Terminal guidance and autonomous hazard avoidance at landing are getting better all the time. So a lander is definitely possible, though I think an orbiter would provide a lot more science about the Pluto system than a lander would.

  • Geoff T

    DTAR seemed to be talking about a human mission to Pluto though (I think?) so I presume my original points are a bit more valid when we’re talking about the significantly greater mass of a human mission?

    I guess everything you said is true for something the size of New Horizons. I presume that option wasn’t taken due to the cost or the transit time required for a slower entry to the Pluto system?

    Thanks for the clarification though! 🙂

  • Hug Doug

    Oh, yeah, a human mission to Pluto would be a very different ballpark!

    Something like Dawn couldn’t have been on the table for New Horizons, Dawn launched a year after NH, and has only recently demonstrated the long-duration use of its ion engines for large changes in velocity. I don’t think the technology was considered mature enough (back in the early 2000s when NH was being designed) to risk a big mission to Pluto on engines that wouldn’t be used for 5 years and then were mission-critical the next 5 1/2 years … and when I say it like that, it does sound super risky.

  • Hug Doug

    It probably would be more like once every 12 years, since Jupiter’s year is ll.86 Earth years long. So you’d launch every opportunity where Jupiter is in position for a gravitational assist.

  • DTARS

    Couldn’t you do solar sail without Jupiter assist?
    Maybe have a nuclear space freighter that crests a giant magnetic field that acts as solar sail for the trip out.

  • Hug Doug

    Yes, but it would take much longer.

    That would be enormously expensive. And far beyond the technology we have today.