Snark

Moderator
  • Content count

    5482
  • Joined

  • Last visited

Community Reputation

6243 Excellent

About Snark

  • Rank
    E Pluribus Boojum

Recent Profile Visitors

7539 profile views
  1. Well, it's reasonably safe to say that Kerbol's emission spectrum is pretty similar to our sun's, and Kerbin's atmospheric absorption / scattering must be pretty similar to Earth's. Why? Because sunlight color in space, sunlight color on the surface, and the color of Kerbin's sky are pretty similar to Earth's. If the spectra involved were very different, either sunlight or sky or both would be a very different color.
  2. Or maybe they're just green. On Earth, there are plenty of green animals, whose greenness has nothing to do with either chlorophyll or their blood-- it's just a skin (or feather, or scale) pigment that provides some benefit from its greenness, such as protective coloration.
  3. Not sure which "you", or which "it", you're referring to here? And are you in favor of having something dramatic happen when the craft passes Mach 1, or not? My own position on the matter is: Frankly, I don't care all that much about Mach 1 per se. I can live without any special effect that happens at the transition. But I'm also fine if they wanted to put one in. That said, I would not be fine with a ludicrously unrealistic, this-never-happens-even-in-movies effect like a "bang" right when it happens. If they did go with something, I don't need it to be hyper-realistic, just not laughably unrealistic. My favorite suggestion that I've heard thus far is @monstah's, since I gather (from my extensive research, consisting of watching The Right Stuff) that things get shaken up a bit as the craft's about to transition, and camera-shake would capture something of the flavor of that.
  4. You send energy in, you get totally random stuff out when it decays. If the energy you send in is modulated-- i.e., data-- then that's just gone. It's not as though the black hole remembers what the data was. Oh, I dunno. Given that the signal takes 1600 years to cross the distance anyway, it's probably okay if the message itself takes a decade or two to complete.
  5. There's no limit to how much power you transmit; you can spray as many or as few photons as you like. If you've got a kilowatt transmitter... or megawatt... gigawatt... terawatt... petawatt... no problem. However, there is a limit to how sharply focused the beam can be, due to diffraction. This is a function of the ratio between the wavelength of whatever you're sending (be it radio, microwaves, visible light, whatever) and the diameter of your transmission apparatus. Discussion here. For a circular aperture, the best you can do is a half-angle spread in radians equal to 1.22 times the wavelength, divided by the diameter. That said, if we're talking a distance of 3000 light years, I think that's doable with current technology and engineering. I forget the exact numbers, but I seem to recall reading that if we used the Arecibo telescope to transmit a message directly at another Arecibo-equivalent telescope pointed right at us, the max range would be something significantly bigger than that. ...did you leave out some zeroes somewhere? We've seen stars a whole lot farther than that. ^ I think that complete inability to send any information across it is kind of what the Schwartzchild radius is about.... Yes, but I don't think 3000 light years is all that un-doable. That's a small percentage of the width of the galaxy, and my impression is that two Arecibos pointed at each other could communicate across that distance. They'd have to be kinda patient, of course, but I don't think anyone's proposing this as a Netflix subscription mechanism. *rummage* *rummage* Ah, here we go. http://www.setileague.org/articles/oseti.htm Even the pessimistic estimate in this paper gives a communication range between two Arecibos as being on the order of 10,000 light years. The optimistic estimate is 26,000. So yeah, 3000 seems doable.
  6. Now that's a neat idea! Really like it. Done right, it could be very immersive to the player-- satisfies the "Hollywood factor", while having a close enough relationship to reality that it doesn't stick in my craw. Could make the "Mach shakes" proportional in some way to the atmospheric pressure, so you get shaken hard at Mach 0.99 near sea level, but it's a lot milder if you're doing it where the air is a lot thinner. I like the idea of a visceral "I've broken through!" feeling when the shakes suddenly smooth out to a continuous dull roar as you pass through Mach 1.
  7. Or maybe kerbals are actually blue (or red, or purple...), and it's just that there's an economically robust cosmetics industry on Kerbin that has managed to convince everybody via a dedicated decades-long marketing campaign that Green Is Beautiful. "There's no beautiful like KerbCorp beautiful! If you're not using KerbCorp Algae Cream to 'release your inner green', you're not looking your best!"
  8. Protective coloration? Mating display? Poor hygiene? There are plenty of green animals. Just not any photosynthetic ones.
  9. Not impossible. Just very, very improbable.
  10. And also pointless, from a scientific point of view, since if he wanted an omnidirectional broadcast across the galaxy, he might as well just broadcast omnidirectionally. Sure, if it's a marketing stunt, "mumble mumble black hole mumble mumble" sounds pretty cool, and there's nothing wrong with that. But if all one is interested in is sounding cool without any scientific justification, why bother asking here in the first place? Sure, for an observer who happens to be sitting in exactly the right spot. And, by extension, observers outside of that spot would get less of a signal. Since the volume of space where the signal intensity would go down is vastly, hugely, literally astronomically bigger than the volume of space where it would go up, then on the whole, beaming towards a black hole would be a net negative if your objective is to get somebody to receive the signal. The original post I was responding to, though, didn't say "focus"-- it said "amplify", and also used the term "slingshot", which seemed to be implying that the black hole would actually be adding energy to the signal, which is not the case. It also was saying that it would scatter the signal (which it would), which is the exact opposite of focusing, and would make the signal harder to receive. And the post was saying that a black hole would be a good target, whereas it would actually be a direction best avoided.
  11. Nope. Scatter, yes. Amplify, absolutely not. That portion of the transmission that doesn't actually intersect the Schwartzchild radius can get bent every which way, but it's not really any different than if it hit a curved mirror. And if you wanted an omnidirectional broadcast, why bother focusing your initial transmission in the first place? Certainly the black hole wouldn't add any energy to the signal simply by virtue of passing by it. The light would gain energy falling towards it, then lose that energy as it recedes again. It's not as if the light beam is performing an Oberth maneuver, or something. At most you might get some dopplering up (or down) if the black hole's motion relative to you has a significant radial component, but again, that's not any different than if it were a mirror moving towards or away from you. Scattering = not concentrated = lower signal strength = harder to receive. So it would do the exact opposite of "amplifying".
  12. Nope, not to any degree that matters. Remember, we're talking multiple orders of magnitude here. Photosynthesis does not work for animals. Really. Not even close. If it did, they'd be doing it already. If a kerbal were human-sized, but shaped like a thin sheet of paper so they had a human's surface area but weighed only a few ounces, and if they went around completely naked and spent all their time sunbathing, then they could live on photosynthesis, as long as they lie still all the time and never move. But then they wouldn't be a kerbal anymore, they'd be a banana leaf.
  13. Sure, in the sense that they get 99.9% of their calories from "snacks" and 0.1% from photosynthesis. Any contribution that photosynthesis makes would be an insignificantly small amount. Photosynthesis has a very low energy production rate, relative to animal metabolisms. We're talking multiple orders of magnitude, here. It's just not meaningfully possible for a large multicellular animal to generate any significant proportion of its own food supply via photosynthesis. There's a reason plants just sit there and don't go walking around. Unless, of course, you want to get all sci-fi with it, such as
  14. Well, not really. It can only be received by a mobile device that's already in front of the signal, which of course excludes you or any other person who was around at the time & place of transmission, because the signal is fleeing from all of us at the speed of light and therefore none of us can never catch up to it. So you'd basically be limited to some hypothetical alien being that, 1. is in the right direction to receive the signal, 2. is far enough away that it's already in front of the signal when the signal arrives, 3. happens to be listening, and 4. can figure out how to decode the signal. But within those limitations, sure. ...yes... but thus the question, why a black hole. As opposed to just beaming it towards some random point in the sky, or towards a star cluster, or something. Sending data into a black hole is sending it to literally the worst possible place in the universe if you want it to be received by anything. It's basically the equivalent of being on a desert island and wanting to send a "message in a bottle", so I write the message down, then burn the paper and grind the ashes into powder and then put the powder into a blast furnace to decompose it to its individual molecules. Very dramatic, sure, but not super effective as a way of getting the message to anyone.
  15. Some very detailed explanations above ... but just to summarize in case this important detail got lost in the shuffle: it doesn't matter which one is more powerful. Because a better antenna is more powerful to transmit, but also more sensitive to receive. It's symmetric. To find the max range at which two antennas can communicate with each other, it's sqrt(A*B). That is, take A's power, multiply by B's power, and take the square root of that. That's the max range, for communication in both directions. You can boost the antenna power of a vessel, somewhat, by stacking multiple antennas. The Communotron-16S doesn't stack. The Communotron-16 stacks linearly (that is, if you have N of them on a vessel, it's N times more powerful.) All other stock antennas are stackable, but with diminishing returns. If you have N of them, they will be N0.75 times more powerful than having just one. There's an enormous quantum leap in power from the HG-5 to the next level up of antenna; it's a factor of 400. So you can use the HG-5 for exploring Mun and Minmus, if you have a direct LOS to Kerbin. If you stack a few HG-5 antennas, then you can communicate from one ship to another between Kerbin and the Mun. But that's pretty much it-- you need better antennas to go interplanetary.