NASA Unveils Historic Pictures of Pluto

An anonymous reader writes: The New Horizons team held a press briefing today and released new data and high-resolution photographs of Pluto. Alan Stern, lead researcher of New Horizons said: "We now have an isolated, small planet that's showing activity after four and a half billion years. We've settled the fact that these very small planets can be active for a long time, and I think that's going to send a lot of geophysicists back to the drawing board."

Comments

Re:Young surface

[Rei]

There's a number of potential fluids at pluto-range surface temperatures - nitrogen, neon, etc. The problem is pressure - but it doesn't take all that thick of an ice pack to get the requisite pressure - I calculate 13-18 meters minimum for nitrogen (depending on Pluto's current pressure), which is only about the weight of a meter of ice on Earth. It has to float, of course, and unlike water their ices sink... when at 100% density. But they'll have pore space in almost any realistic situation. And there's always lighter types of snow, such as methane snow, which don't require any pore space at all to float.

More to the point, anywhere that these sorts of snow preciptate out deep enough, in the right temperature conditions, they'll melt on the bottom. If the ice is condensed on a slope, the liquids will try to flow out. If they find a way out, they'll freeze, pressure will rebuild into it bursts open, then a refreeze, and so on, like pillow lava spreading on Earth - possibly with cryogenic equivalents of lava tubes as well. Where there's no path for liquids to flow, you could have something akin to arctic sea ice.

Note that pressure is only part of the key, temperature matters too. But these sort of conditions are quite plausible on Pluto. And more to the point, since there's a range of potential liquids at Pluto temperatures but with different properties, you could have some rather complex interactions with dramatically different properties at different depths and massive events when the temperature or pressure on the surface changes beyond a key point.

Oh, I almost forgot about this effect, which could be a serious weathering agent. Freezing nitrogen can be a bit.... dramatic. ;) Here you can see some of the craziness it does when going between phases, starting around 50 seconds in. Certainly looks like something with significantly more erosion potential than water ice freeze-thaw on Earth.

Re:Question about deep space pictures

[Rei]

Do realize that LORRI isn't just a camera, it's actually more of a telescope. And they can expose the images as long as they want, and even stack them if they want.

If you think it's hard to get pictures on the sunlit side, that's nothing - they actually plan to try to get pictures on the side *not* lit by the sun, just by the pathetically weak light reflected by Charon. Getting images on the lit side is easy, but the dark side is going to be very difficult, involving lots of stacking.