SPACE

[Dio]

What's the surface material, though? Frozen methane, even nitrogen? Those things take a crapload less energy to move around than rock does...

[pogo]

The problem is it should have no energy, be geologically inactive. All the planets were active at one point. Their assembly from rocks coalescing and smashing together would have released immense amounts of energy, The larger the body the more the energy and the longer it takes to cool down.

But almost all have lost that energy. Our moon for example is a cold dead rock with no geological activity to disturb its craters. Geologically active bodies are either much larger or are affected by strong tidal forces, such as Jupiter’s moons. Pluto is smaller than our moon. Charon is much smaller.

I wonder if it’s due to asteroid impacts. Objects hitting the moon will be mostly those in orbit around the sun. Many icy ones will lose their ice due to the action of the Sun, as comets. And there is no evidence for anything other than rocks hitting the moon. But Pluto could be colliding with Kuiper belt objects on a regular basis which are still icy, containing water or other ice, some of which melted on impact.

[zip accident]

Our moon for example is a cold dead rock with no geological activity to disturb its craters.

Our moon has one face towards us at all times. It is therefore not affected by tides. The moon goes around the faces of the Earth, which is therefore strongly affected by it's tides. The faces of the Earth also move with respect to the sun, so that affects us tidally too. Pluto is far from the sun so less affected by it's tides, but Charon is much closer than our moon is to us, so it's tides will be in strong effect. I don't remember whether Charon has one face always pointing at Pluto, if not Charon will also be strongly affected by tides.

[pogo]

The tidal effects of the Moon or the Earth would be minimal though. On Earth we know the effect very well and it moves the oceans but not much else. The effect would not be enough to melt ice, never mind rock. Only Jupiter is known to exert enough tidal force to trigger geological activity, and only on its innermost moons.

Anyway Charon and Pluto are tidally locked. The same faces of them face each other all the time. Tidal warming is non-existent in such cases.

[zip accident]

The tidal effects of the Moon or the Earth would be minimal though.

We don't know that. We know that multigigatons of water move under tidal influence. I think it's quite likely that tidal forces are significant in Earth's geology. The rocks in question are part molten, maybe due to other causes, maybe not, but anyway being semi molten they would be influenced much as the water is, and there's a lot more rock than water.

Anyway Charon and Pluto are tidally locked.

Hm, seems they are. That's one explanation out of the window then.

[Dio]

But almost all have lost that energy. Our moon for example is a cold dead rock with no geological activity to disturb its craters.

No geological activity, but it's not a "cold dead rock". Current thought is that it does have a stil-molten core.

[Firefox]

Some insight into why the last SpaceX rocket launched blew up:
https://www.reddit.com/r/spacex/comment ... onference/

(edit) From the horse's mouth, though actually less detailed if anything:
http://www.spacex.com/news/2015/07/20/c ... ion-update

[merman]

16 months worth of data still to be downloaded from New Horizons, while it travels out to the Kuiper Belt and studies more objects. And all for less than the cost of an NFL stadium.

[pogo]

Another picture of Pluto. Source, which promises more images Friday. From that page

A newly discovered mountain range lies near the southwestern margin of Pluto’s Tombaugh Regio (Tombaugh Region), situated between bright, icy plains and dark, heavily-cratered terrain. This image was acquired by New Horizons’ Long Range Reconnaissance Imager (LORRI) on July 14, 2015 from a distance of 48,000 miles (77,000 kilometers) and received on Earth on July 20. Features as small as a half-mile (1 kilometer) across are visible.

So mountains, craters, light bits, dark bits, and non-specifc ice. Well duh.

[Dio]

The flatness of the grey of there makes me think whatever it is is a very diffusely-reflecting material. Dust or snow. Note also that the shaded part looks bumpier than the flat part. And is that the sort of bumpy terrain you might expect from glaciation in the top centre of the image?

[KlaxonCow]

Interesting thought.

That the flat bits we're seeing are not solid rock. They're a layer of dust / snow / ice on top of the solid rock - which, if we could only remove that layer on top, would probably be cratered all to Hades underneath. The jagged mountains are poking through that layer.

If this is the case, then it explains the flat bits on Pluto without requiring volcanic activity - and, thus, not requiring a ton of energy, we know not where from.

The snow / ice is melting and re-freezing constantly - possibly with some kind of "rain" cycle redistributing it? Any atmospheric "winds" would redistribute any dust about the place - and, in its liquid / dust form, it'll naturally find a level under gravity, flattening itself out.

The dark bit in that image is an area not covered by this dust / snow / ice stuff, for whatever reason, and that's why that bit is, indeed, cratered all to Hades, as we were more expecting to see from Pluto. The dark bit is the exposed underlying solid rock. Ergo, that's the "real colour" of Pluto.

The other bit is a (rather thick, it seems) layer of dust / snow / ice, which is in some kind of cycle of melting / re-freezing / re-distribution that means it regularly flattens itself out (as liquids - or dust, with a bit of "wind" pushing it around - under gravity will naturally find a level) and is sitting on top of that darker solid rock.

Of course, pure speculation from two or three images, so it all could be a load of shit upon further examination.

But it would explain away the chief mystery of why Pluto's surface doesn't look quite like we expected. We're not looking at the solid rock in those flat bits. We're looking at a layer of constantly melting / re-freezing ice sitting on top of it (and, of course, when I say "ice" there, I don't mean water ice but something like methane ice, which has a lower melting / freezing point than water ice, commensurate with the fact that it's extremely bloody cold out there at Pluto and that that kind of ice, with the lower melting / freezing point, requires much less energy to be swirling around for the melting / freezing cycles to occur. It still requires some energy, mind you, but far, far less than the idea that it's rock melting / solidifying in volcanic activity and, therefore, should be much easier to explain where it's coming from).

[Mark]

Interesting...

NASA Has A "Huge Announcement" To Make...

...NASA is set to announce the major discovery of a new planet by the Kepler Space Telescope tomorrow (July 23) at noon EDT (5 p.m. BST).

http://www.iflscience.com/nasa-announce ... ch-it-live

[pogo]

The flatness of the grey of there makes me think whatever it is is a very diffusely-reflecting material. Dust or snow. Note also that the shaded part looks bumpier than the flat part. And is that the sort of bumpy terrain you might expect from glaciation in the top centre of the image?

I think that’s just as the Sun is not directly behind New Horizons. It’s more to the top right of the picture, judging from the light and shade on the craters and mountains. And it does look quite shiny and reflective there.

I can’t imagine there’s glaciation, as in flowing glaciers. That would require precipitation, and so a proper atmosphere, which if it had it lost long ago. I’m still skeptical that it generates much activity itself, which leaves collisions. It’s not hard to imagine a fairly energetic decision dumping ice on it or melting ice already there which then freezes. That would explain the un-pockmarked nature of it – it just happened fairly recently.

[pogo]

Pluto’s other moons, in greyscale and enhanced colour

[gumboot]

I can’t imagine there’s glaciation, as in flowing glaciers. That would require precipitation, and so a proper atmosphere, which if it had it lost long ago.

Surely a glacier can form from any material accretion, from simply passing through a dust cloud or whatever.

Don't know about the gravitational requirements, though.