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r4pt0r

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Very interesting tweets from Caltech's Mike Brown, AKA the discoverer of Quaoar, Sedna, Eris, Makemake, Orcus and many others:

The dominant feature on Pluto is the dark (but not quite continuous) equatorial band. This was nicely explained in 1996 in a paper by Hansen and Paige who showed how nitrogen evaporates from the warm equatorial regions and reaccumulates at the poles, leaving dark substrate behind. Dark substrate is probably tholins. Tholins = organic muck.

Here's a figure from that 1996 Hansen & Paige paper showing how Pluto's surface ices move around with time. The solid line shows the latitude of the sun w/time, the dark regions show where the ice has evaporated, white is ice.

CJvn4I1UMAA-ZRI.png

We're approaching the 2029 summer solstice after which most of the northern ices might have headed south. Process already starting now.

Why is the dark equatorial band not continuous? No clue. The "heart" looks like the brightest spot on the surface, and it's equatorial. It could just be random feedback. It's bright, so reflects sunlight, so cold, so gets icy, gets brighter, gets colder, etc. Still, weird that it is at equator. Maybe something interesting going on there. Keep your eye out.

North of the dark equator are the patchy tropics. Summer has started here recently, so I suspect this is where ice is currently evaporating and going poleward. Come back in 20 years and it might look just like the equator. Again, nicely modeled in Hansen & Paige.

What are the polygonal features? Not polygons. Seems unlikely any physical process could form large scale linear features of that sort. Your eye is good at playing tricks on you. I suspect that on the nicely imaged side you'll see no giant polygons.

OK, what about Charon? Still too low detail. I want craters, damnit. And I want them now. But I will have to wait. On Charon the brightest spots are likely to be ammonia rich water ice flows. Dark spots not dark, just lack of water flows.

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I just had a very sobering though. After this encounter, the next time we see a whole new type of world will be when we send out our first interstellar probe, and see a whole new star system up close. It likely won't be in our lifetimes.

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I just had a very sobering though. After this encounter, the next time we see a whole new type of world will be when we send out our first interstellar probe, and see a whole new star system up close. It likely won't be in our lifetimes.

There are plenty of bodies in the solar system the size of Pluto. The only difference is that they don't have the history of Pluto. We'll likely send some probes to these bodies within our lifetimes (C'mon, Sedna Probe!)

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There are plenty of bodies in the solar system the size of Pluto. The only difference is that they don't have the history of Pluto. We'll likely send some probes to these bodies within our lifetimes (C'mon, Sedna Probe!)

Sedna has an even more fascinating origin than Pluto, in my opinion. Our current best explanations for its extreme orbit: 1) interaction with a yet-to-be-discovered planet 2x as massive as Earth lurking in a circular orbit at 70 AU 2) interaction with a passing star 3) capture from a nearby solar system. I repeat, capture from a nearby solar system! We could have a proto-exo-planet-thing in our own solar system and haven't realized it yet. If we miss the 2076 chance, I'll be quite angry

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I just had a very sobering though. After this encounter, the next time we see a whole new type of world will be when we send out our first interstellar probe, and see a whole new star system up close. It likely won't be in our lifetimes.

Psyche is going to be a lot 'newer' than Pluto, given we've already had a good look at Triton.

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Don't think Sedna will happen unless the tech to make a flyby becomes pretty cheap, or propulsion allows an orbiter to go there.

Someone else said it, but I think this marks the end of flybys. NASA doesn't have unlimited funds and they realize the amount of science you can gain from orbiters and rovers is higher then just by a flyby. I think a Uranus and Neptune orbiter takes priority to any flyby to another Plutoid.

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Sedna has an even more fascinating origin than Pluto, in my opinion. Our current best explanations for its extreme orbit: 1) interaction with a yet-to-be-discovered planet 2x as massive as Earth lurking in a circular orbit at 70 AU 2) interaction with a passing star 3) capture from a nearby solar system. I repeat, capture from a nearby solar system! We could have a proto-exo-planet-thing in our own solar system and haven't realized it yet. If we miss the 2076 chance, I'll be quite angry

I'm very keen on seeing if the carbon-oxygen white dwarf star associated with said encounter/capture is found. The few known of, I've started looking into, but not enough data is available ... need proper motions.

Did you start that Mission to Sedna page?!? Nice! :cool:

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Don't think Sedna will happen unless the tech to make a flyby becomes pretty cheap, or propulsion allows an orbiter to go there.

Someone else said it, but I think this marks the end of flybys. NASA doesn't have unlimited funds and they realize the amount of science you can gain from orbiters and rovers is higher then just by a flyby. I think a Uranus and Neptune orbiter takes priority to any flyby to another Plutoid.

I agree, an ice giant, Cassini-style orbiter is the next major similar thing we need. I'd rather visit Neptune. Uranus has rather boring satellites and is by itself a bland bluish ball. Neptune has incredible winds, prominent clouds and of course, Triton.

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I think a Uranus and Neptune orbiter takes priority to any flyby to another Plutoid.

NASA has an actual priority list for large missions, as part of the decadal survey, and it puts a Uranus orbiter third after Mars sample return and a Europa orbiter. Given Europa and MSR projects have both officially started, an ice giant orbiter is likely to be the flagship after those.

Edited by Kryten
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NASA has an actual priority list for large missions, as part of the decadal survey, and it puts a Uranus orbiter third after Mars sample return and a Europa orbiter. Given Europa and MSR projects have both officially started, an ice orbiter it is likely to be the flagship after those.

Awesome. I know I read that some actually think despite Uranus seeming rather bland during the Voyager visit, that it would be the more interesting target over Neptune if you had to pick. I don't know why if someone could shed light.

Also pluto-annotated.jpg?itok=BYcYpyhC

New Pluto Image!!

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I know I read that some actually think despite Uranus seeming rather bland during the Voyager visit, that it would be the more interesting target over Neptune if you had to pick.

Voyager 2 flew by Uranus at quite possibly the most boring time it could have. Since that flyby, it's developed cloud bands similar to those of Saturn.

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