Picture reversing the time vector. Do you think you can gently throw an object to Charon escape just by choosing some clever trajectory? No? Then why do you think it will work that way and land with a gentle velocity with time flowing in the opposite direction?
That's the point. The escape velocity on Charon is 580 meters per second. So even something with no momentum when it arrived at Charon would be falling at 580 m/s (1300 mph) when it hit the ground. Picture shooting Mount Everest into the ground at that velocity. Is this really what you'd expect to see as a result, it holding together and just sitting in a hole? Of course not, it'd shatter and explode massively, kick out a rim, fill in the transient crater with debris, etc - aka, a crater forming event. And that's the bare minimum impact velocity, realistic impacts would be far harder (dozens of kilometers per second) in the overwhelming majority of situations..
I love how Alan Stern and the rest of the team go through lengths to call Pluto a planet. This time he even laid particular emphasis on calling Pluto-Charon a binary planet.
Great team. Great project. Great results. Just amazing.
It's really weird. I've heard a lot of people speculate that it's just an asteroid that "landed gently" in Charon's low gravity or something by being on a really lucky trajectory. But it just doesn't work that way. Picture running the time axis in reverse. Does one think that there's a particular trajectory that they could pick the rock back up and throw it back into space without requiring a lot of energy? The fact is that even on a body like Charon, big chunks of rock can't just gently settle down.
It's just a really weird thing to see.
It seems more complicated than that (even ignoring that impacts don't generally make heart shapes). For example, have you seen the carbon monoxide data? It's all clustered in that area. Why would an asteroid make carbon monoxide cluster there?
There's some really interesting things going on. Take a look at this picture and think of what it looks like to you:
Link.
Doesn't it look like... well... a shoreline?
Now take a look at those fractures in Sputnik Planum - notice how they have a curious inner ridge:
Where else have we seen that before? Oh right, Europa:
It's the shape of a liquid welling up through a crack and freezing due to a drop in pressure.
To me, this shows all the signs of a cryosea underneath an ice cap. Which leads to the question: can that occur on Pluto? And the answer is, "probably". With N2, CO, and CH4, you can get eutectics with triple points as low as 51K (a naive solar equilibrium-temperature calculation for pluto's surface, without any other sources of heat, reaches up to 55K). Add neon into the mix and it gets down to 24,6K. The key is, these liquids can't exist on the surface - they require pressure to exist. Which means that they can only exist as aquifers and subglacial lakes/seas. Pure nitrogen requires about 18 meters of pure nitrogen ice (more because it'd have pore space and be mixed with lower density ices). Pure neon would require about 3x as much.
The flat areas in Tombaugh Regio have two radically different appearances. One is the aforementioned area that looks like sea ice with frozen cracks (Sputnik Planum). The other is what's being called a "pitted" terrain. The latter touches the "shore" of the regio, while the former is deep in the middle (at least, from the pictures revealed so far). If one wanted to step even further out onto the limb here, they could posit that the "pitted" terrain involves these ices sitting directly on "bedrock" (which in a pluto context here is water ice), while the terrain that looks like sea ice would have liquid dozens of meters or more down.
But this is all just along one line of thinking. There's just so many possibilities right now. One notices, for example, similarities with various pluto features and frost-heaving earth features like pingos and ice wedges. But it could be something completely new entirely. This isn't water we're dealing with.
A real crazy thing is to think about how there might be vertitable explosive processes on Pluto. Solid nitrogen that forms due to decompression undergoes an energetic glass to crystalline transition. And overall does really weird stuff when freezing (start about a minute in).
Also note that there is nitrogen being lost from Pluto. Lots - 500 tonnes an hour. Over geological timeperiods, that's a massive, massive amount. Pluto loses its atmosphere 2 1/2 orders of magnitude faster than Mars. And yet it's still there. So where's it coming from? The team already pointed out that there doesn't seem to be a planetwide layer of deep nitrogen ice. To me that only seems to leave the possibility that it comes from deeper within the planet. But for it to move from deeper within to the top means a fluid (an aquifer), not an ice (either that or serious tectonics dragging up 500 tonnes an hour!). And given that Pluto's crust provides pressure, it's easier for nitrogen to exist as a liquid than a gas in such a situation.
My mother sometimes sends me checks from the states. The bank cashiers are always confused by them and have to get their managers, who eventually sign off on them. The last time I was at the bank with a check the cashier spent several minutes insisting to me that they can't accept checks before going back and getting approval.
Checks have no place in this modern world.
Good to see you guys catching up on credit cards. When are you going to finally modernize your banking system as well?
Anyway, I can attest to the point of this article, in Iceland you see those little portable card readers (I don't know what they're called in English, they look like this) everywhere, whether it's someone walking around between tents at a campsite collecting the day's fees or some unknown band playing a little gig in a bar - a lot more often than you see them in the states.
The main problem with this solution is the amount of power the fan would draw.
Solar Impulse is a 30kW airplane. Cooling fans are nothing compared to that. Furthermore, I also wrote: "Or if you want it to be passive, a greenhouse window opener to open up the insulation when it gets hot".
This isn't rocket science here. Everyone who works with large format battery packs knows that you can't just cover them in foam insulation and pretend that's good enough. You don't have to go to the sort of extremes Tesla and GM go to - Nissan's Leaf doesn't even use cooling fans. But it does use cooling channels with passive forced air coming from the car's motion, as well as pad heaters to warm them up when it's too cold. Because they're not so daft as to think that you can just pack them in insulation and call that good.
They probably know more about batteries than you will ever learn.
You know nothing about me, let's leave it at that.
They are attempting something very difficult that hasn't been done before, There will be problems.
As I said - "I'm not faulting them for their oversight - bad decisions happen in every engineering project."
But as I also said: "But this doesn't strike me as any sort of unusual nor unexpected situation. News flash, temperature-sensitive batteries need proper temperature regulation rather than just being slathered in foam, details at 11...."
Building a manned solar powered airplane to make such long runs is very much a new and challenging thing. Designing large format battery packs, not so much.
Potassium nitrate foliar spray!
What's wrong with, you know, a simple thermostat-controlled fan, like most large battery packs use? Or if you want it to be passive, a greenhouse window opener to open up the insulation when it gets hot?
I'm not faulting them for their oversight - bad decisions happen in every engineering project. But this doesn't strike me as any sort of unusual nor unexpected situation. News flash, temperature-sensitive batteries need proper temperature regulation rather than just being slathered in foam, details at 11....
Or maybe he meant "morel boost". I mean, they're based out of California so some trendy hipster food with wild mushrooms and the word "boost" in the name might be what's needed to get the job done.
"Yes, André, I finally finished replacing the batteries. But, wait a minute, what's this?..." (BAM! BAM!) "Oh damn it, I just noticed that there's some serious cracks in the fuselage! I'm going to need several more months to get her flightworthy..."
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.
I'm glad to see this finally coming to a head. It seems that every last bloody body that we've encountered in the solar system has been the same story: "Wow, this is showing signs of activity, we expected it to be a cold dead world because it's too small....". It's about time that people accept that there's something we've been overlooking in terms of heat release. At least one thing, possibly multiple in different situations.
MESSAGE ACKNOWLEDGED -- The Pershing II missiles have been launched.
