itstimaifool

I really liked this movie. I felt the same way about the "documentary" feel, but then I learned that it was all filmed on a (relatively) very low budget, so it's pretty impressive that it's as high-quality as it is. Anyway, the Europa lander: That's amazing, I can't wait. In my opinion, the best-case scenario* is that exploration of Europa plays out a little like it did on Mars, with a series of "Ooh that's interesting, let's take a closer look!" missions, culminating in an under-ice mission. That'll make for an exciting next few decades. *More accurately, the best-case scenario that actually has a chance of being funding. Strictly speaking, the absolute best-case scenario is that all war stops and we divert all military funding to NASA and get into a nice pattern of launching a new billion-dollar space mission every few months. But I'll settle for the more-realistic incremental approach.

I actually forget where I first saw it, but I know it wasn't 9gag. I'm not actually sure what 9gag is, to be honest...

So it seems that a main disagreement here is a matter of semantics. 'Numbers' could mean two different things: 1- The symbols that most humans currently use to represent quantities, which look like this: '1234...' 2- The concept of quantities in the universe. So basically, whether 'numbers' means the symbols or the idea they represent. The same problem exists for the definition of 'math.' I intended those words to refer to the underlying idea, rather than the symbols humans invented. Obviously, the symbol that looks like '2' is not a fundamental universal constant, it's a result of the development of written language. But, since I'm terrible at writing down my ideas, this came across rather ambiguously. Sorry for that.

Of course, I didn't think of this question, I saw it on the internet. I'm just curious as to what the citizens of the KSP forums feel about this: Were numbers and math invented by people, or are they a fundamental attribute of the universe that we gave words and symbols to? By 'numbers' and 'math,' I mean the underlying ideas that those represent. Obviously, the symbol that looks like '2' is not a fundamental universal constant; it's a product of the development of written language. The same goes for the symbols '=' and '+'. But these symbols represent meaningful ideas, just like the string of symbols 'cat' represents an organism that exists in the universe independently of that string of symbols. So in the context of this thread, the words 'numbers' and 'math' don't refer to the symbols, but to the ideas that those symbols represent. (I'm sorry that this is probably worded terribly. Things always sound better in my head than they look written down.) This is a mostly philosophical question, and I can see evidence for both opinions. On one hand, 'quantity' seems like a fundamental aspect of the universe. If you have 2 apples, no matter how you say it or what symbols you have, there's still two apples. It follows, then, that if you add two more apples to the pile, there's then 4 apples. Call it what you want, but adding 2 apples to a pile of 2 apples results in a pile of 4 apples. So it seems that math was discovered by people, and all we invented was a set of symbols and words to describe it. But on the other hand, higher math, like calculus, is a lot harder to justify as "fundamental." A lot of laws of physics seem to fit nicely in with math, but is that because the universe is fundamentally mathematical, or because we humans invented math to explain the universe? In my opinion, math was discovered, just like the laws of physics. However, my only justification is "If the universe is not fundamentally mathematical, the how else could it be explained without math?" which seems like a pretty weak argument. So what do you all think?

I'm imagining a small craft being launched with an EMDrive into orbit, and when it's fired up, it instantly accelerates to a fraction of the speed of light sufficient to destroy the Moon on impact. Later, scientists discover that they misplaced a negative sign in an equation. But more on-topic, I have a question (I'm sorry if this has been answered previously in the thread). A main concern with the EmDrive is that it violates the conservation of momentum. But in order to do this, the drive must use energy. And as far as I understand, matter and energy are interchangeable in some respect. So, can't the drive's loss of energy be compared to a conventional engine's loss of reaction mass? And therefore, using some sort of math and science I don't understand, could it be shown that conservation of momentum is not violated? I don't know anything about theoretical physics, so I'm sure that above paragraph is painful to read for those who do. Please help me be less wrong in the future.

The rest of your post is valid (at least, I can't find any immediate problems with it), but this is not. You can use electricity from an arbitrary renewable source to electrolyze water into hydrogen and oxygen, which can be used as rocket fuel. Obviously, this isn't the best fuel for every scenario (if it was, it would be the only fuel that's ever used), but it's at least an option.

I used a poor choice of words in the poll and in my original post. Rather than saying "Humanity" I should have said "Any life, intelligence, or culture directly descended from or created by humanity." You all make some great points: A billion years from now, a negligible chance that there will be a recognizable human civilization. Culture, technology, and biology all change, and changes in one of those cause changes in the other two, so it's inevitable, given enough time, that humanity will cease to exist in it's current form. But I think that descendants of humanity will exist for a long time to come. And by descendants, I don't just mean biological parent-to-child descendants. We could develop artificial life or uplift existing species. We could create intelligent robots that reproduce and evolve like life does. We could all life inside a giant computer simulation. And then all of these creations of ours could do the same thing again. But you would still end up with a descendant of some sort from current humanity. This is what I meant in the original poll.

NOTE ABOUT THE POLL: "Humanity" was a poor choice of words. I should have said "Life, intelligence, or civilization descended from humanity." Call me an optimist, but I think that human civilization (or at least a descendant of us) has a strong chance of lasting billions of years into the future. That is, if we maintain a strong space program. And by "human civilization" I mean whatever species or civilization evolves from us. Since it would be unlikely for any species to last a billion year without evolving to be almost unrecognizable, and even less likely for a culture to last a thousand without such radical changes. Now I know this sounds kind of absurd. Billions of years? That's a lot. But look at it this way: Why not? The obvious answers are things like huge asteroid impacts, horrible climate change, disease, nuclear war, etc. But all of those things only affect one planet at a time. If we get some extraterrestrial colonies going, then there will always be a few people left after these sorts of disasters. And I think it would be entirely feasible to put a colony on Mars within a few decades, if only there was enough funding for the space program. So here's my question: Assuming that all of the space programs around the world get an arbitrarily large boost in funding, why would humanity not last for a billion years?

(This has already been mentioned, but I'm going to go into a little more detail) There's some common misconceptions about space and heat. First of all, let's define heat: Heat is the vibration of atoms within a material. If something is hotter, then the atoms vibrate more. Space doesn't have any atoms to vibrate, so it doesn't have a temperature.* Stuff can be cooled by two methods**: Conduction and Radiation. Conduction is the transfer of heat by contact: When a hot thing is in contact with a cold thing, the atoms vibrating very energetically in the hot thing tend to smash into the atoms vibrating slowly in the cold thing. These collisions slow down the atoms in the hot thing and speed up the atoms in the cold thing. As a result, heat moves out of the hot thing and into the cold thing. Radiation is heat transfer without physical contact. When things get hot, they glow. This is obvious in things like lava and molten metal, but it's true of everything. Humans are hot enough to glow in infrared, which can be seen with special cameras. Energy is needed to make this glow happen, though. This energy comes from the heat of the object. Therefore, the heat of an object will gradually decrease as it is turned into light and escapes. This is how things cool in space, since there is no material to be in contact with. This is why solar panels and wings make good radiators and fuel lines don't: They have much more surface area, which means much more area that can glow, which means more energy is able to escape as light***. Also, it's already been mentioned, but nuclear engines need to be hot to run, and even if you feed it cold fuel, it's specifically designed to heat up fuel to ridiculous temperatures anyway, so it won't make much difference. *Technically, there's a little bit of dust and gas drifting through space, but it's little enough that it doesn't really matter. **I think it's technically three. Convection, which is heat transfer by moving fluids, being the third. But I don't quite understand how this is different from conduction, so I'm lumping it in with conduction. ***There's also other factors, like the material they're made of, but I don't know much about this, so I'll just leave it at that.

Yes, but that's not an option for unmanned craft. (That particular craft was unmanned, but I guess I cropped a little too close to see that)

That's a fair point. However, you could also use realism to argue the opposite point. If two different countries on opposite sides of the Earth want to launch a satellite into geosynchronous orbit above their country, you can't really do that with one satellite at all.

Oh my god, how did I not think of this?! I'm going to try this ASAP!

I definitely love this idea. If not a procedurally generated part, then at least like a subassembly with randomly-chosen parts. Either this, or make the satellite disappear (or at least become uncontrollable) once the contract is fulfilled. But either way, it's a single-player game, so everyone's free to do what they want. I personally have 'abused' this a few times when I was short on cash, but I try not to do it too often. (When I have done it, I like to imagine the company that paid to put the satellite in orbit being really confused when it suddenly left its orbit to go to the Mun. "What are you doing with our satellite?!" "Read the contract. We said we'd put it there, not keep it there." *Kerbal lawyers snicker in the background*)

I had thought I made them public, but I guess I messed up somewhere along the way. That's exactly what I did. If I had not done that, then the pictures would have shown up as the little "missing picture" icon like they did. Anyway, got it all sort of sorted out. I'm using a free trial of imageshack, so the pictures will disappear in 30 days, but nonetheless, let's get this thread back on track, shall we?

Uh oh. They work for me, but they are from Dropbox, so there might be some permission issue. I tried using Imgur, but the site just refuses to load for me. EDIT: Ah yes, I signed out of dropbox and now they don't work. I'm currently trying to fix it.