Jump to content

Nikolai

Members
  • Posts

    524
  • Joined

  • Last visited

Everything posted by Nikolai

  1. Irrelevant. You can make a von Neumann machine out of anything that has state and the means to change that state. Whether that state is a function of electric fields across tiny capacitors or the location of I-beams mounted to large wheels makes no difference whatsoever, except in terms of trivial things like space occupied and speed of computation. If you had a large enough beach with enough seashells, enough time, and the rules to manipulate them, you could precisely duplicate KSP. Heck, you could even have someone hand you the C# code after you got the pebbles and rules together, and if your shells and rules duplicate a von Neumann machine, you could compile it and run it on your seashell computer. The FPS rate would be pretty pathetic, though.
  2. I have no idea why not. Maybe he doesn't understand physics. (Physics is hard.) Or maybe he can't get past the idea that difficult concepts can be communicated with little green muppety things that look like characters from a children's cartoon. Or maybe he doesn't know enough about the program and how it works to understand its educational potential. I remember talking to a good friend and theater major in college when she asked, "So what do engineers do, anyway?" I answered that, in a sense, we're professional inventors; it's our job to know how the universe works in a practical way so that when someone needs a machine to do something, we know how to build a thing that will do that with a minimum of time, money, and effort wasted on guesswork. To illustrate the point, I gestured toward her stereo. "That CD player? Someone had to design that. They needed to know how to put all the parts together so that it would work." What surprised me is that that blew her mind. It had honestly never occurred to her that someone, somewhere, had to know enough about electronics so that they could sit down and make decisions about how her stereo would be designed and assembled. She was fairly smart, and if she'd ever been asked to, she probably would have been able to invent something kind of like the design process. It had just never had a chance to cross her mind, so it was an entire way of understanding and dealing with the world that she was (unintentionally) blind to. I don't know your dad, obviously, but my experience has taught me that when people don't understand things, it's usually simply because they've never had much reason to give it much thought. I'm also something of a hopeless optimist when it comes to educating young people about science. Maybe all he needs is some idea of what you've learned and how you learned it. If there's a cure for his lack of understanding, it lies in communication.
  3. Oh, I know. It's all part of her personality, it seems to me. For as long as I can remember, she's always been the sort to watch, wait, think, and watch again. For as long as it takes until she thinks she understands it. I can't tell you how amazing that is to me. (The downside, if there is one, is that it can take her longer to do some things than you probably think it should. But you can be sure that when it's finally complete, it will be done as well as she knows how.) When it came to MS Paint, that meant going over the flag -- the part she wanted to focus on -- pixel by ever-lovin' pixel. I'm pretty sure I'll have to buy her a tablet when she gets older. Or a bunch of model rockets. Whatever she wants to do, I'm sure she'll be good at it; she wouldn't let herself not be. I often find that I just have to find things that capture her interest and get the h*** out of her way, just offering guidance or support when she needs it. It's an amazing, awe-inspiring thing when the wind hits her sails and she just goes, faster and further than I ever would have guessed she could.
  4. All great stuff, thanks. It's easy for me to get hip-deep into the math; obviously, most kids have a limited attention span when it comes to that sort of thing.
  5. Here you go: She made it when she was seven, and was pretty proud of the flag. You can't see much hardware outside of the spacesuit.
  6. In which reference frame are you measuring the distance to these stars?
  7. If it helps, GoldenShadowGS, this relativistic velocity-addition formula works for objects moving much more slowly, too. It's just that it will give you results that are really, really close to simple addition/subtraction; it's not that the rules governing things suddenly and magically know to shift over to a different set of equations once things start getting "fast enough".
  8. Right. Your example involves ship A and ship B as seen from a third reference frame, and then implying that that third reference frame is the "right" one. According to relativity, there is no "right" frame. So ship A would see the third reference frame receding from it at 0.75c, and ship B receding from it at 0.96c. And yes, the relative velocities of things will change depending on what your chosen reference frame is. But no one can claim that their preferred reference frame is "correct", or that it represents in a singular way how things are "physically moving".
  9. You're right in basic principle, but not in this particular example. Being in orbit around something involves an acceleration, and accelerations are not symmetrical.
  10. They'd be able to perceive each other. And they wouldn't be physically moving at 150% of c. That's because shifting coordinate axes from one velocity's frame of reference to the other has to be done in a way that's a bit more complicated than mere addition/subtraction. If you were on ship A, your definition of "meter" and "second" would be different from that of ship B. More to the point, what you would report about ship B would be different from what ship B would report about itself.
  11. Actually, that's very humble, noble, and responsible of you. Working things like that into your daily language is a good reminder that any knowledge anyone possesses is provisional, and that we can all be taught something.
  12. I already have four of his wallpapers rotating on my desktop every thirty minutes. She loves them. On her own desktop is a picture she made in MS Paint depicting a United States Moon landing. (It looks about like you'd expect an MS Paint depiction of that to look; the Earth isn't quite round, and the shadows are wrong, and things aren't shaded at all. But I adore it.)
  13. That reminds me of a story one of my favorite engineering professors told about going to see the great Dr. Richard Feynman give a lecture in freshman physics. The lecture hall was one of those with all the blackboards up front, where you could scribble on one, then push it up on tracks and continue writing on another board behind it. He'd filled about six boards deriving some Newtonian physics equations and working through an example; when he got to the end, he said, "That's not right." He had enough intuition about what numbers communicate to know when he was getting the wrong message. So he went back over his work. As he was trying to find the error, a student in the front row was frantically waving his hand and calling out, "Dr. Feynman! Dr. Feynman!" Finally, exasperated, the physicist turned around to address the student. "What?!" he barked. "Up there, on board number two -- you dropped a pi." Feynman looked to where the student was pointing. "Hm. You're right." There was a pause. "You know what? F*** the pi." ... And he turned the lecture into how to know when you're getting it wrong, even if you're pretty sure you applied the right concepts and equations. I admired the man before that story, and even more so afterwards.
  14. I feel like I should be the one congratulating (and thanking!) you. I discovered your "Project Rho" website some years ago, and was inspired by your conversational and engaging writing to try to make basics of rocket science understandable to kids. Until KSP, I lacked the proper tools (I tried a few times to lead classes for older kids with model rockets with very limited success). In a sense, I hope that my daughter will teach me what I need to know before attempting to figure out how to reach broader audiences more effectively.
  15. Well, yes, but we haven't gotten into a discussion about fuel lines (never mind going even further into more advanced strategies like asparagus staging) yet. I figured she didn't need them for getting a one-Kerbal capsule to orbit. ... And that's exactly what she does; I recommended to her that she not go faster than about 200 m/s before getting above 11,000 meters or so. She understands in an intuitive way that it's a waste of fuel to try to go too fast too quickly (because you have to get more air out of your way). I'd describe TWR to her, but she's only just learning (integer) division and starting to get a handle on fractions. I understand the technical details of what you're saying; in fact, working out those details is one of the reasons I love KSP (and even enjoyed technical details about rockets back before Windows -- excuse me, "MS-DOS Executive" -- even existed). But it's also rewarding to watch her try to develop a feel for it on her own, and a welcome challenge to try to break down information in a way that she can understand when she has questions. It's all worth it to see her sheer delight when something works the way she wants it to. (Every once in a while, she likes to check on the progress of my Vall orbiting station, and I kind of get the sense that she's taking mental notes. She's perfectly content to work on understanding things in stages -- she has a drive to master things on her own -- but I have no idea what her ultimate goals might be. I'm looking forward to being surprised.)
  16. Isn't that small black ring beneath the decoupler and the ASAS a SAS unit? As for the rest, I think she'll work it out. She likes to experiment. And we still talk about how she wants to do stuff. She told me this morning that after she learns to dock, she plans to put a docking port on each stage and de-orbit debris so that her near-Kerbin space won't end up as cluttered as mine. Actually, shortly after her orbital success, she put some landing gear on it, took it out to the pad to try it out... and was disappointed to find out that the demo's landing gear don't reach past the end of the engine bell. So she's looking forward to "better" landing gear, too. The "improvement" that immediately occurred to me was to ensure that the radial decouplers fire after the four tanks/engines around the core and before the engine on the bottom of the core. But hey, she made it work. I'm sure she'll try to make the design even better.
  17. That she does, and it makes me proud. She's always trying to explain herself and what she thinks, especially when she builds things; I think the precision she needs to describe what she is doing and what she wants to do accurately has made her a very good and careful speaker.
  18. Sure, if I can get this right. Remember that these screenshots are from the demo (0.18.3), so the launch pad and launch tower are still there. She's eager to play without them (as well as build some rovers) as soon as she finishes her reading homework this evening. These screenshots are taken with an older computer that's set aside for her use, and it's showing its age, so the screenshots are smallish and the resolution somewhat lacking. Here it is on the pad. Bill looks unimpressed. (Jeb is in orbit at this point.) The thing balances pretty well. She didn't use angle snap. And here it is from more above. She likes the nose cones. It's a pretty basic design; most of her challenge involved when to perform the gravity turn. She ended up in a roughly 80 km x 200 km orbit, which was good enough to get the registered version.
  19. That's possible. I read the admission as "Maybe I made a mistake" and not "I made a mistake" -- as if you weren't quite positive, and needed reassurance of what reality really acts like. But maybe I failed to understand properly. My apologies if I came off sounding boorish.
  20. She finally did it! I told my eight-year-old daughter she could get a full version of Kerbal Space Program if she stuck with it long enough to get a rocket into orbit. I'd help her as much as I could, and answer any questions she might have, but I wouldn't build her rocket or fly it for her. She worked at it for a while, but got distracted by a Disney game she got for Christmas. I thought I might have missed my window to get her interested. Last night, she came running up to me. "Dad! Dad! Dad! Come look!" -- and she took me to the computer and proudly moused over the periapsis and apoapsis in the map view. Both were higher than 70,000 meters over Kerbin. She didn't have enough fuel to get back, but she couldn't have been any more pleased with herself. Grinning from ear to ear and just beaming with happiness. She had done it. So, first thing this morning, I set her up with a store account and got her her own copy of KSP. We'll download a full copy of the game when I get home. Thank you, devs, for the opportunity to share spaceflight with my daughter in such a way that she can see why it's so interesting and so much fun to me, even though she's eight. And you should hear her talk about technical issues surrounding spaceflight with her friends! ("I was going to turn retrograde and land, but I ran out of fuel. It doesn't matter, though; Jebediah looks pretty happy anyway.")
  21. How about a planet with a depression in it, with some material in the depression that is undergoing radioactive decay to form a gas that is being released from the rocks? So within the depression, there's an atmosphere. Outside it, though, there's nothing. (So if you're willing to go in a hole, you can use a parachute to slow your descent. Otherwise, you need rockets.)
  22. Thank you. You put that much better than I did.
  23. There's no such thing as "the speed of everything that isn't you". Not to put too fine a point on it, but you can't look outside and say, "Oh, everything else is moving at x" (where x is some singular velocity). Everything will be moving around at different velocities with respect to one another. You could take some kind of average, perhaps, or come up with some other mathematical scheme to come up with a reference frame you'll call "fixed" for convenience's sake. But it's not as if every object will be moving past your ship at some fixed speed; using the objects alone, you won't be able to tell what "stationary" is to resolution much better than a few hundred kilometers per second. And even if you could, the best you could really offer is "I'm moving at the same speed as these objects to within such-and-such a resolution". I'm trying to point out that there's no sense in which things "outside" your ship "would have to be fighting the speed of the universe". There's no such thing for them to "fight".
×
×
  • Create New...