ZetaX

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About ZetaX

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    Rocket Scientist
  1. Theoretically, yes. Practically. no. You would need to accelerate it to reletivistic speeds for this to truly matter. At some point the blast will also become more and more cone-shaped.
  2. Terawatts is a very small power output when compared to such a thing.
  3. You could also use solar winds. For example, add some huge surfaces that can open to outside space to let particles (and hence impulse that would otherwise push against the sphere) out on the side farthest from the star.
  4. No, it requires exactly zero energy to let something hover. We already know many things that hover one way or another (permanent magnets and diamagnetism/superconductors, balloons, ships, ...), none of them putting any energy into it. One can surely build something that wastes lots of energy on it (think helicopters or rockets), which is due to other reasons such as maneuverability or speed, but not a requirement.
  5. No. Here is problem sheet for you: http://spacemath.gsfc.nasa.gov/blackh/4Page33.pdf .
  6. I am not sure. Radiation is proportional to 1/r², but the orbital speed increases as well (at ~1/r, but that's a rough approximation); thus they stay that close only for a comparably small amount of time. Hence the amount of radiation might be comparable to that of the other parts of the trajectory (still not good if it heightens cancer chance by another 10% per person). But it could be that more radiation in less time increases the risk significantly, e.g. due to the body having no chance to regenerate. Then they are screwed without a shield of some kind.
  7. [quote name='Findthepin1']Sedna?[/QUOTE] There is no unexplained irregularity in Sedna's orbit. It follows its path as predicted. That it has a rather non-standard elongation has nothing to do with unaccounted mass.
  8. While theoretically correct, we are pretty sure that the amount not accounted for is very small. We do not see any relevant amounts of mass, and we are not observing any unexplained irregularities in the orbits of planets. It probably has nonetheless been measured anyway.
  9. [quote name='peadar1987']So where do you think this energy is coming from? Radiogenic heat? About 22TW. Human energy consumption? About 15TW. Insolation? [B]174,000 TW[/B]. [/QUOTE] Or to make his numbers even more ridiculous: use the energy actually produced by the humans themselves. Lets use the numbers from [url]https://en.wikipedia.org/wiki/Human_power[/url]. By that even if all humans were exercising 24/7 at peak potential, we would only have aroung 1.2TW of usable power produced. In practise, this ignores losses due to the conversion of chemical energy inside humans, but it also ignores that humans obviously do not exercise 24/7; those two should about cancel each other. Some other sources talk about 120W total energy consumption of healthy humans. So yeah, the above should be about right.
  10. [quote name='*Aqua*']My dictionary doesn't know "absed". What does it mean?[/QUOTE] *based (as someone already said)
  11. [quote name='*Aqua*']You'll need an RNG which works with so-called 'big integers'. Afaik there's none and big integers are [I]slow[/I]. Also the number of combinations are so huge that you'll see patterns in the generated data caused by the design of the RNG algorithm (that's one of the reasons why they are called [I]pseudo[/I] random).[/QUOTE] That's all wrong. The principles RNGs are based on generalize to arbitrarily high number. See for example the Mersenne twister, but almost any other should do. You might have to find some library or code it yourself (depending on what language you use), though. For some older ones (quadratic congruential generators and such) you might get patterns, but modern ones are made to avoid those as good as possible. Even if there are patterns, they would only be visible after huge amount of uses, where "huge" is a number much bigger than the number if requests I expect that page to get (or, if done right, higher than the amount of atoms in this planet). Big integers are a non-issue as well. Naive implmentations (of something like 100 000+ digit numbers) are slow, but we have fast fourier transform-based multiplication and such. But I don't think you would even need that. Take a 1024 bit number, which is very small in comparision to what would already be possible, and you should never encounter a problem. That will be mroe than enough data per picture to work with. In total, this is just an elaborate version of my first post on this.
  12. I can only second what Camacha said. He is 100% correct that locking threads because of a few participants is not working too well. It gives the trouble-makers (e.g., but not only, trolls) even more power: not only disrupting threads, but even getting them locked.
  13. [quote name='peadar1987']It's always night but... It's also ALWAYS DAY! Mind. Blown.[/QUOTE] Actually it is only always day. You would need a rather weird definition of "night" to be able to claim otherwise. Yes, it is dark, but I wouldn't take anyone seriously who closes the curtains at noon and then proclaims "night". Seeing stars also can't be it, otherwise every cloudy day is "night". And so on.
  14. [quote name='ChrisSpace']How much energy would I need to completely remove the earth's axial tilt? In other words, how much energy would I need to make the earth's rotation lined up with its orbit around the sun?[/QUOTE] This cannot be answered without more information on how it is done I think. You want to change angular momentum, which is conserved. Hence you need to put it somewhere. It should be like with specific impulse: you can either spend more energy or more reaction mass. You could calculate the exact angular momentum, but that will not give you the energy. For example, you could try to change the axis by shooting packs of rock into space. Theoretically, even a single rock the size of your fist would suffice, but you require absurd amounts of energy then. Or you could somehow abuse the moon or the sun (those, followed by the planets, are also what mainly influences the tilt in real life) for it, which gives you much more reaction mass to work with, leading to significantly lower energy usage. if you can somehow tie the entire Milky Way to this, then the energy probably becomes laughable (but to actually get there you would probably require absurd energies again). By doing a very very precise prediction you could maybe abuse the chaoticity of the system to just throw a rock into space now and then wait for a billion years for it to do all the work itself.
  15. [quote name='Mitchz95']This is something I've often wondered about. We have millions of pieces of debris floating around in LEO; what's going to be the cumulative effect of those things re-entering over the next few hundred years?[/QUOTE] Nothing. Maybe one of the few larger ones strikes a house. That's about it.