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

Wait... What?

[mark-t]

Did he just say ... "planet"?

Orbits are cyclical

[fyngyrz]

Alan Stern, lead researcher of New Horizons said: "We now have an isolated, small planet that's...

I TOLD you it was a planet. :)

link to image

[the_other_chewey]

TFS contains a link to tha NASA main page, and to a finished
live stream on an unrelated media site, now without content.

Way to go!

NASA press release, with picture.

Young surface

[Dan East]

The detailed image showing Pluto's mountains is, according to one of the NASA scientists, one the youngest looking bodies in the solar system. The surface features appear to be less than 100 million years old. Very strange. Are there even any viable theories on what is providing the energy to resurface such an old, far-out, isolated body? A major impact of some kind is the only thing I can think of. Pluto is too small for the heat to be internally generated, and there is no massive nearby body to cause tidal forces and the like.

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:Umm forgive but

[ThorGod]

watch the feed. What they've discovered so far has already challenged and thrown out many hypotheses about planet formation/evolution. It may look like a rock to the untrained eye - but what humanity knows about planetary physics has already changed because of this probe. It's impossible to know where and how this will change our theories and even technology down the road.

Re:Question about deep space pictures

[Solandri]

The main imager (LORRI) is a 208mm diameter telescope with a 2630mm focal length, or f/12.6. The spider and secondary obscure 11% of the area, so that's equivalent to f/13.4 in terms of light gathering for photographic purposes. Exposure times are 50-200 ms, or 1/20 to 1/5 sec.

On Earth, the sunny 16 rule says on a sunny day the proper exposure at f/16 is when your shutter speed is 1/ISO. So f/16, 100 ISO, 1/100 sec. The atmosphere absorbs roughly half the sunlight, so in earth orbit that would become f/16, 100 ISO, and 1/200 sec.

Pluto is about 32.6 AU from from the sun right now, so the sun's brightness there is 1/32.6^2 = 1/1063 what it is at Earth.

Going from f/16 to f/13.4 gets you about 1.43x more light.
Increasing exposure time from 1/200 sec to 1/10 sec gets you 20x more light.
That leaves a deficit of 37.2x, which you can get by increasing CCD sensitivity to ISO to 3,720.

ISO 3200 was easily attainable by high-end consumer digital camera sensors 10 years ago, much less a commercial one specially designed for scientific purposes.