Awesome
Literally.
Yet more pictures of Pluto and its moon have been sent back to Earth from NASA's New Horizons spacecraft – this time indicating a colossal geological upset in Charon's past. The latest spectacular images of the satellite orbiting the remote, icy dwarf planet reveal what NASA boffins have described as "a belt of fractures and …
Look at the northern hemisphere vs the southern hemisphere below the "crack". Then go back to the north, like, at the top where that monster, stained impact area is. It hit something or something hit it with such force that it nearly tore the planet in two. The entire northern hemisphere has ample evidence of the pressure from the impact. Prior to the impact, the little bugger probably looked like the southern hemisphere. Relatively smooth with normal impact craters and then WHAM. Do they not want to scare people by telling them the truth, that space is a flippin dangerous and deadly place and really bad sh*t happens on a pretty regular basis? "The truth? You can't handle the truth !"
Because Nature loves symmetry. But only so much.
(Also, seriously awesome in a Kelly Freas painting kind of way)
(Also, the pebble density out there still seems high judging from the charonic pebbling; can we conclude something about the dustyness of the Kuiper belt?)
Trying to picture this. A spherical water layer overlain by a thick crust of water ice. The water freezes and expands, lifting the crust and forcing it to crack.. into only two pieces? That would create two hemispheres with a lot of uneven pressure underneath. Unless, the freezing was slow enough to allow new ice to flow into the voids?
Still, it seems a lot more likely that the crust would just fracture into polygonal shapes similar to a dried mud flat. Columnar basalt also fractues in that pattern, and sun-heated sandstone can also crack like that. All of them are strongly subject to uneven expansion and/or contraction.
The direction, mass and any electrical charge/release of the colliding body could account for it. Before the impact it was more or less a nice sphere. It no longer is. If even 10% of the sphere were forced down and to the left as in this picture, the crack is precisely where it should be. Someone very experienced in working with clay could probably make a prototype or has even seen the effect themselves. I would bet the iron stain that is offset from the crater is the direction the other body went after the collision. All of the dust and junk the collision kicked up could have followed the body with more mass but the moon pulled some of the dust and maybe some big chunks back to its surface. I'd bet good money there are some large rocks/chunks from another astral body on that moon.
Alternatively, compare with Mars. Northern hemisphere sunken and smooth, Southern rugged and cratered.
One hypothesis for that is a giant impact on the North, forming a crater nearly as big as the planet.
So possibly a giant impact on the South of Charon, leaving a smooth crater? And that ridge and canyon belt is the crater wall - not as big as might be expected, as the low gravity means a lot of the debris would have been splattered wider or escaped.
The pictures are censored. Don't trust everything you as to what they want them you to look at.
What you think is an impact crater caused by natural rocks in space hitting planets on a regular basis is highly likely just something else.
And I bet there are a lot of artificial buildings and structures in that area.
They aren't daft. Something has given Charon a pretty good whack over the top, as anyone can see. Exactly what remains the question, could have been a graze with Pluto itself, could have been something else. It'll take a bit more study to figure out what exactly happened there.
The thing is, impacts on *that* scale tend to more or less liquify the whole planet, at least nearer the sun, and with rock involved. Charon is, as far as the data tells us, mostly ice, at temperatures approaching near-absolute zero K most of the time. I could be wrong, but given the very fancy physics of water around its melting point, it may well be that the kinetic energy of the impact *did* cause part of Charon to melt, and "near-instantaneously" refreeze, with the contraction/expansion action of the briefly liquid water around the 273 K mark breaking up the top half in the manner we see.
Charon (and any sizable moon) cannot graze its primary without being well inside the Roche limit. Even a near-miss would pull Charon (and maybe Pluto) into many pieces, causing a lot more scarring than one crack, even assuming the pieces merged again after. Then what was Charon comes around again and the process repeats, probably ending in a major impact that disrupts the system entirely.
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The thing about the Roche limit, is that the strength of its effect is directly related to the depth of the gravity well.... The force of the Roche effect for both Pluto and Charon would simply be ..negligible.., and certainly not enough to rip either one apart if they'd scuffed each other. Compared to the kinetic energy involved the Roche effect would be an afterthought.
Given that Pluto captured Charon somewhere in its history, and their relative masses, it's not unlikely their early marriage may have been.. rather exciting.. before their orbit stabilised into the one we see now. Anybody got a decent cluster I can borrow for some marbles-in-space simulations? [/innocent]
"The thing about the Roche limit, is that the strength of its effect is directly related to the depth of the gravity well...."
At first approximation, the Roche limit is related to 1.26x the radius of the primary (Pluto) multiplied by the cube root of (density Pluto / density Charon). Or you can re-algebrize that to 1.26x (Radius Pluto) x cube root (mass Pluto / mass Charon).
Using the mass-based equation and noting a ratio of 8.62, you get: 1.26 x (1186km) x cuberoot (8.62) = 3064km for the Roche limit.
Noting that's the center-to-center distance for the two bodies and Charon's radius is 605km, you get about 1275km surface-to-surface separation.
"The force of the Roche effect for both Pluto and Charon would simply be ..negligible.., and certainly not enough to rip either one apart if they'd scuffed each other"
Since the surface-to-surface separation is non-zero, that means that the Roche effect would make a difference before the two bodies physically hit. Charon would be torn apart before scuffing Pluto.
"The team is discussing the possibility that an internal water ocean could have frozen long ago, and the resulting volume change could have led to Charon cracking open"
You know what, I'm never going to complain about a burst frozen pipe again after reading that sentence...
"I'd interpret as an ice glacier covering the northern hemisphere with the orange crater as an "ice volcano" source"
If you recall Pluto itself is largely red. Its chemistry suggests that its colour might be from an CNH-based aniline(?)-type of dye. If Charon managed to scuff Pluto without falling apart, or was hit by another debris object with similar chemistry, the 'ice volcano' might also be a dye, or just rust. Has anybody got spectroscopic data on these surfaces?
An unrelated report speaks of the Deccan Trapps accelerated volcanism that created most of India's plains being linked to the impact of the 7-mile asteroid that hit the Caribbean area. Translated to Charon the topping impact in the 'north' would possibly create sympathetic volcanism in the south. Flows from the widespread cracking from that could account for the smoothness of the southern hemisphere while recapture of impact debris would account for much of the chaos and pitting in the north. If the impactor was also rocky, and embedded itself asymmetrically initially, that would help with the localisation of the earlier recapture impacts in the north until the rock migrated through the icy layers of the interior into the moon's centre of gravity.
I'll just leave this here, and walk away...