cubinator

Closing the door!

Thanks! Yes, I can play bits of it. That was the movie score that inspired me to learn to play organ.

Best of luck.

Yep, those few minutes when the Sun's surface is completely covered up are the only time you can look right at it without protection. Its atmosphere is an object you'll only ever see in that moment unless you go to space. It's no brighter than the usual daytime sky, which means the light from the corona can't possibly penetrate the filters that makes the rest of the sun safe to look at.

Additionally, if the sky is decently clear you should start looking for the planets when the sun's about half covered. I could see Venus and bright stars like Spica well before totality. This year's eclipse will give us a nice lineup of four bright planets. Dim Mercury I was never quite able to spot in 2017, so I wouldn't spend too much time looking for it - there are at least a dozen better things to see, and it's too dangerous to get out binoculars. Watch for news about comet 12P as the eclipse nears - it's getting close to perihelion and has a small chance of gracing us with an outburst that might just render it visible in the sky near Jupiter. My far-out hope is that there will be a CME erupting right before the eclipse, though, solar maximum and all. But first on the list is my hope that the clouds will stay away!

Probably. I was browsing some eclipse links online today and finally learned just how many food trucks, ticketed events, and private property parking for sale is going to be occurring in every small town along the path in Texas. It's going to be, at best, mild madness.

It is time to have plans made, and almost time to start watching the weather. Climate is a lot more menacing this time around, with the majority of the path being under frequently cloudy regions. In 2017 it was pretty easy to just head out into the desert and be pretty sure it would be clear. Still, this has been a year unlike any other. What are your plans?

Pi Day means it has to go at least halfway around.

I do like the Star Wars TF2 show.

At the very least, it's a very different climate than where I live, and I am biologically and geologically inclined, so I will be content with walking around in some natural park looking at the plants and dirt and bugs! Also mountains. I have not been around a mountain in a year. I will be happy to look at them.

That is a very interesting point about cold water! Still pretty deadly though... Nice to know my math sounds reasonable! My intuition is to take everything I said as an absolute maximum. Any water on you that's spread thinner than whatever I assumed it was will freeze faster, and I didn't even get into heat transfer through skin. Man, I want to see windchill in W/m2 now, that makes way more sense from a physics perspective. Frostbite in x minutes is a useful metric where I'm from.

Thanks! Sounds like a cool complement to the pipe organ pizza place. Thanks! Pima is on my radar, there's definitely way more there than I have time to see!

I'm going to spend a weekend in Arizona for some presentations there, but will have a large amount of free time as well. I basically will have one day in Phoenix and one day in Tucson - any suggestions for cool things I should see during that time?

The thing is sitting on the Moon, is working just fine, it isn't in a million pieces, and it was going less than a thousand miles an hour when it hit the ground. This is a "soft landing" accomplished in my book. Of all the milestones to fail during a moon landing, tipping gently over at the very end is the least concerning. They'll figure out what happened, and if the next one doesn't stand proudly upright they can just build wider landing legs.

I wonder if they can get that third-person video of the landing and tipover, from that camera that they apparently launched out of the side(?). That would be especially exciting.

I might do some math in a bit regarding the actual heat transfer (math below), but qualitatively in the meantime: Have you ever seen someone dunk a bouquet of flowers in liquid nitrogen for a few seconds, then take them out and shatter the flowers like glass? It's that cold. I've frozen wet ice cubes together in an industrial freezer at somewhat survivable temperatures in just a few seconds - I think on Titan you'd have a hard time even drawing in your first unprotected breath as your mouth and nose freeze shut. Disclaimer: I just googled around for some heat transfer coefficient values and eyeballed a fairly low fluid velocity arbitrarily The heat transfer rate is going to depend on the heat transfer coefficient and the temperature difference. For air, I'll say the heat transfer coefficient is 25 and the temperature difference is 21 degrees (assuming dealing with surface body temperature of 25 degrees). In that case the heat transfer rate is 525 W/m2. For Titan, I'll assume the heat transfer coefficient is 1.5 times that for air (not really sure of the exact value) and the temperature difference is 205 degrees. In this case the heat transfer rate is 7687.5 W/m2, almost 15 times more. For water, with a temperature difference of 21 degrees and a heat transfer coefficient of 5000, the heat transfer rate is 105000 W/m2. So water seems to be quite a bit better at wicking heat than Titan's air, but let's see how much of a threat it is anyway. Water (which you contain a lot of) has a specific heat capacity of 4.186 J/g*degree C. So if you have 1 mL of water in your mouth spread over an area of, say 10 cm2 or 0.001 m2, at a temperature of 310 K, the temperature would need to be lowered by 37 degrees to reach the freezing point and begin to form ice, corresponding to an energy of 154.88 Joules. At the heat transfer rate we calculated earlier for Titan's air, and taking into account the smaller area, if you drew in a breath at 2 m/s or so, the water in your mouth would reach 0 degrees Celsius at t=20.15 seconds. Ok, so that's not complete instant solidification, at least in your mouth. For comparison with my example from before, liquid nitrogen apparently has a heat transfer coefficient of 300 to 800, around the same as air. That means that indeed, imagining dunking stuff in liquid nitrogen is a decent analogy to what would happen to it on Titan. And while we've found out that swishing liquid nitrogen in your mouth *might* not *instantly* freeze some of your spit, I think we can be absolutely sure that for no amount of time would it be pleasant. Furthermore, your eyes are more exposed and likely a bit cooler than the inside of your mouth, so we can be sure that should your face be exposed to the atmosphere you would have significantly less than 20 seconds before your eyelids start to freeze. You might be blinded around the same moment you realize there's no oxygen in what you're breathing - a frightening scenario. Anyway, it seems that Titan is definitely very dangerous to expose your face in, but if you should accidentally expose some skin out of your jacket, say, with your glove loose around your wrist, you might have up to 20 seconds to get your glove back on before you start getting serious frostbite - and beyond that, there is no mercy. All of this assuming you don't touch a rock with your bare hands, wade in the shores of Kraken Mare, or encounter a gust of wind in your totally rad wingsuit, any of which would make things much, much worse.

I may be wrong on this, but it's also possible at least some of the crew went to bed.

Discussing roll orientation of the lander...

I dunno, it's basically a bunch of companies independently having a 'first try' at landing on the Moon, isn't it? If if was one company that had had five tries I'd see it differently. I hope the congress critters can see past that too. Well, I don't think the lander they'll be trying with is going to be "small"...

The air pressure is no problem, people withstand way more when going underwater in submarines or diving. The temperature is cryogenic (like liquid nitrogen range) so you need to keep yourself insulated and avoid skin contact with the air, as it will start freezing your flesh solid on contact. Since the air is more dense than on Earth, it'll also be more effective at transferring heat out of you. You also need your own breathable air supply, of course, and make sure your airways are sealed against the atmosphere, because the methane is quite poisonous. Water is probably what most of the ground is made of, so if you dig some up and warm it up you can probably do whatever you need with it. If you're keeping your habitat comfortably warm, then you should make sure the part of it that's sitting on or right above the ground is not conducting any of that heat. The first problem would be that it would not be efficient. The second would be that it would start melting the ground...and your habitat would start to sink. If you've got so much hot air inside your habitat, though, you might consider one that allows itself to lift into the sky as a balloon.

Cylinders and spheres are not only for following streamlines in-atmosphere, they are also the best structural shapes for pressure vessels. So we won't see a complete absence of them in space.

It flies, but barely. Ditch the wings when flying slow over the drop zone.

Here is a half-decent full run of the song! https://drive.google.com/file/d/1eJNyOO_gWe2kSr3xCTyLc6531jMTuNi1/view?usp=sharing Played on my Conn 800 at home.

Re: high volcano walls: Run a ski/cable lift down the side.

Iclicked this.