cubinator

What if the aliens communicate by warming up different parts of their body?

Yep, and you can see dust being kicked up in the videos of the landing. He wasn't talking about the video, though, because apparently that's completely different from the pictures. A comparison I thought of later is expecting a helicopter to kick up a crater as it lands. It's unreasonable because the thrust is so spread out and primarily used to displace gas, not rock. Displacing rock to slow down is called lithobraking.

Remember that lifting reentry is still necessary at Mars. But it would reduce risk on return to Earth, and passengers could rest at least a little easier as they come home.

Hmmm, that seems like a fairly good idea in general, as Mars ships would spend a while in orbit getting topped up by other ships anyway.

Today I spoke with a flat Earther. He seemed respectful, so I engaged with him to try to learn a bit about how these people work. I wondered what he had to say about experiences I've had which indicate Earth to be spherical. I opened by complimenting his shirt, which had a map of the world printed on it and was legitimately a pretty cool shirt. He had an unusual sense of perspective - he seemed to believe that we cannot see things that are far away. He said our perspective at sea level is about 3-5 miles (Hilariously, that is correct) but that it was because of some inherent inability to see further than that, not because of Earth's curved surface. He payed me no mind when I told him about the time I was at a beach in Rio de Janeiro, and could see a white buoy when standing but not when squatting. He didn't understand that you'd be able to see it at any altitude if the water wasn't curved. He said that if you could see a little ways, but the horizon obscured further things, that would indicate being on the surface of something like a marble (that is also correct???). I don't think it quite clicked for him that these were things I had seen and observed myself, not anyone telling me (his mode of Flat-Earth-ism seems to be that we are being lied to by NASA, etc. and "brainwashed to NOT investigate". Ironic that I've investigated this on my own and found him wrong.) I also told him about the time I measured the distance to the Moon by parallax. He believes we cannot see craters and features on the Moon because it is too far away. I told him about the existence of telescopes and that they use simple optics to work. (Optics and windows are touchy subjects for people of this philosophy, I know.) I expected him to ask how we know the Moon is closer than the stars to be able to use parallax, to which I would have replied that I once watched the Moon pass in front of Aldebaran. However, he instead went a different direction (towards the Moon landing conversation) and asked how all those craters, supposedly made by meteor impacts which should come in from all sides, all end up perfectly circular. I don't know why this is, and I told him as much, but I will find more information later on that. (Pretty sure Scott Manley or such has a video on it.) He then asked something interesting. He asked if I had ever seen one of these meteors impact the moon. Yes I have. I saw the meteor that hit the Moon during January's lunar eclipse and was recorded by many astrophotographers. Again, he payed little mind to my experience. He wondered why pictures from Apollo missions show no crater formed by the lander exhaust (because craters don't form in that material from such forces? I dunno). ===== It was a little insightful, nice to see him being more or less respectful and conversational instead of yelling at people like some of the Bible-waving people, but I still feel perplexed and a little sad afterwards. I think his main issue was his idea of perspective. If he can understand that we can actually see distant objects if they are large enough, he might have a chance of understanding the geometry of the horizon at sea level, and also that the Moon is actually kind of large, allowing us to see it. (Has he ever seen the Moon? I honestly don't know. He's probably never been to the ocean.) I asked for his name, and he was reluctant to give it to me (I suppose he was recording the entire thing, probably for his flat Earth Youtube channel) but he did just say I could call him by his channel name. I told him the reason I asked was so that when I am on Mars years from now, I will carve his name into a rock so that he can be remembered there for all eternity! (I also have the name of another space denialist I've encountered which I will carve as well.) The two of them will be honored for eternity in the very place they refuse to believe is possible. ====== Update: I've looked at his Youtube channel, but I haven't watched any videos. I'll maybe check out the one I'm probably going to be in. Although he was reluctant to give me his name, it's displayed all over his stuff... I'm recovering from this experience by playing Space Engine with all the lights in my room off. Works every time.

We should just redirect asteroids into Earth until it stops rotating, thus saving us from having to worry about what time it is ever. In all seriousness, Daylight Saving Time doesn't actually give us more daylight, it just shifts what part of the day is dark a little. Totally useless.

Chickens.

There is life in the universe.

My keys wouldn't work in a mirror dimension...

If you want to go high and fast, you might want to look into actual solid rockets as well. They are much more predictable to launch and pretty safe to handle. There are a number of sources online for parts you can buy to make your own rocket, and simulate it in OpenRocket or RasAero to try to get the best performance.

Indeed. And if you want a high ascent, you need to know whether the cork or the bottle will pop first. More energy for ascent means more pressure needed in the tank (at least for this kind of propulsion) and that means greater danger. You should know what to expect so that all that energy goes into something fun and not something painful.

You'd want to know the pressure ratings of your tank and any valves you use, and do some math with the gas laws and stoichiometry to figure out how much pressure to expect from your ingredients and whether the tank can handle it. If you're around any pressure vessel that might explode, you should definitely stay far back, wear safety eyewear, and preferably have some kind of physical barrier to stand behind. Even an exploding soda bottle can create dangerous shrapnel. If you go for higher pressure, you might want to find a way to begin pressurization remotely, so that you don't have to be holding the tank at all.

Maybe you could keep the chemical the same, but produce a better pressure vessel and nozzle. My guess is that baking soda+vinegar will give a higher Isp than plain compressed air and water. If you did it in something like a scuba tank, with a nozzle on the end, you might be able to get much higher altitude. Hydrogen peroxide makes a great oxidizer, but not only would you be dealing with an actual liquid rocket, at the concentrations needed it tends to explode on its own. Not recommended. A typical water rocket might benefit from household peroxide, though, as it is heavier than water and would therefore give you more reaction mass.

@adsii1970 I'm still listed under 'aspiring dreamers' but would probably be better placed in 'Currently attending university'. I'm studying Aerospace Engineering at the University of Minnesota (following Robert Gilruth's footsteps!), in my second year now. Still with the goal of being some kind of rocket scientist and an astronaut.

Terraforming Mustafar would definitely be a good idea.

Cat. (erpillar)

More parts = more versatility in what I can create. Potentially, that includes a more complex version of the Rubik's Cube I once created in KSP1.

Cassini crossed the ring plane in the space between the ring and the planet, where there was very little material. If it had crossed any thicker parts of the rings it likely would have been terribly damaged.

So what I'm hearing is a 4x4 Rubik's Cube

... _ ._ _.__ (STAY)

I watched Interstellar tonight, and there were a few frames with a post-it note that had some information about a galaxy on it. Since the starfield in the new galaxy is very unusual, I didn't think it could be real but this galaxy is in a cluster. I'm flying there in Space Engine right now to see how well it matches. Update: it's just as exciting a sky as in the movie. Now scanning for black holes with earthlike planets!

Earth has been around for one third of history.

I hope they poke it with a stick to see if it really is soft.

Do not feed bananas to the Magic Boulder.

I see. Well, more left for me then!