Activity for Canina
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Answer | — |
A: Could a civilization without access to computers have cryptography? In two words: absolutely yes. Cryptography, at its core, is not about computers at all. Sure; automated, programmable, electronic computers operating at about a gazillion instructions per millifortnight allow us to perform some pretty neat tricks that would be difficult to pull off otherwise, but th... (more) |
— | over 7 years ago |
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A: Neutron Star materials - If a neutron star stops spinning, What will be the characteristics of the materials in it? Let's go more with the scenario you are describing, than the question you start out by asking (which appears to be only peripherally related). Let's assume that a "pebble" is approximately 1 cm3 in size. Let's also assume that one of these adult men can carry somewhere on the order of 75 kg. Let's... (more) |
— | over 7 years ago |
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A: What would allow an epidemic on the scale of the Black Death to happen again? For ultimate spread and mortality, you want something that has the following properties in combination: High probability of infection when somebody is exposed to the disease (highly infectious) High probability of transmission of the disease after being exposed, but before developing visible sympto... (more) |
— | over 7 years ago |
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A: End-user experience and prominent use cases of robust interplanetary internet Actually, there is a network with properties similar to those that would likely be seen on an interplanetary version of the Internet. We can use it for comparison. It's called FidoNet. FidoNet uses a store-and-forward architecture to cope with high cost of long distance transfers, and batch process... (more) |
— | over 7 years ago |
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Would humans be able to derive nutrition from foodstuffs found on alien planets? Suppose humans have developed the technology to travel between star systems. This might be some science-fiction method like warp drive, jump drive, peanut butter drive, hyperspace drive or whatever, or something vaguely scientific like the Alcubierre drive. The specifics of the means of propulsion do... (more) |
— | almost 8 years ago |
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A: Science-based FTL drive TL;DR: "Scientifically correct" (according to current established science) and "faster-than-light travel" cannot be used in the same context without some form of negation. What you are asking for is not possible within the boundaries of science as we know it. Here's why: Our best model for this typ... (more) |
— | almost 8 years ago |
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A: Can there be a moon within a planetary ring? Yes, you absolutely can have a moon orbiting within a ring system. In fact, we have a perfect example of that in our own solar system: Saturn's A ring has the Encke and Keeler gaps, wherein orbits the moons Pan and Daphnis, respectively. So if you want a ring system with moons orbiting within it, go... (more) |
— | almost 8 years ago |
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A: Water-based computer Like others have pointed out, such a computer already exists. Not only that, it looks like it was done long before electronic computers; take for example the water integrator, built in the Soviet Union in 1936, capable of solving mathematical problems (but it doesn't look like a general-purpose, prog... (more) |
— | almost 8 years ago |
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A: Is it possible to orbit inside a gas giant? Like JDÅ‚ugosz wrote, what will cause problems in the scenario you describe isn't so much your orbit as the fact that you are within the gas giant's atmosphere. I'm going to use Jupiter here to have some specific gas giant to use for examples. Feel free to look up the relevant data for any other gas... (more) |
— | almost 8 years ago |
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A: Would a horseshoe orbit planet be able to travel to their partner planet? Well, we did travel to the Moon with 1960s (and some even 1950s) technology. We also had reasonably detailed plans to use the same underlying technology to make a year-long Venus fly-by mission in 1973-1974, but as we know, we never made the trip. So technology on its own likely wouldn't have been th... (more) |
— | almost 8 years ago |
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Given present-day Earth as we know it, how could I fake a radio transmission as coming from a distant star? Setting: Western world nation, Earth as we know it, May 2016, Gregorian calendar. Eccentric billionaire, large multinational corporation or similar; lots of money, and ability to enlist the help of some really smart people. Let's say that I, for some nefarious or benevolent purpose (doesn't matter) ... (more) |
— | almost 8 years ago |
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A: Could a planet be at the center of the universe, yet still have a sun? Not as commonly thought of, no. One of the things that we learn in orbital mechanics is that the planet orbits its star, not the other way around. More generally, the less massive body orbits the more massive body. When the difference in mass is large ($m1 \gg m2$), that's a good enough approximatio... (more) |
— | almost 8 years ago |
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A: What can cause the aliens not to understand our signal? Like AndreiROM points out, recognizing that there is a signal, and understanding the contents of the signal, are two completely different things. In fact, it's not even a given that the aliens would recognize some of our transmissions as deliberate transmissions. For an example of this, consider ult... (more) |
— | almost 8 years ago |
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How can I set up the environment so that my creatures don't get sick? In a world I am working on, I have a wilderness-living, social, group-living species that for various reasons lacks access and ability to anything resembling modern medicine, including vaccinations. Yet, I want to keep it such that absent physical injuries, adults of this species very rarely become v... (more) |
— | almost 8 years ago |
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What natural processes can cause a sidereal day to be significantly longer than a sidereal year? Most of the planets that we know of have a sidereal day (rotational period) that is shorter or on the same order of magnitude as their sidereal year (orbital period), the latter being the case in tidal locked bodies. Without invoking magic or super-advanced technology, is it possible for a planet to... (more) |
— | about 8 years ago |
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A: How far away would an alien civilization need to be for us to not notice them? For the TL;DR, see the bottom of the answer. See also What would it take to get a message to another star? on Space Exploration SE. We can approach answering this by considering how sensitive our most sensitive receivers on Earth are, how much antenna gain we can muster, how much power we can must... (more) |
— | about 8 years ago |
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A: In a world with escape velocity greater than the speed of light, would a civilization be able to reach space? No, they will not be able to reach space. At least if we assume that our understanding of physics is correct. Since you do not state anything to the contrary, that's an assumption I am willing to make. Basically, what you have is a (very small) black hole. A black hole is a mass that is so dense tha... (more) |
— | about 8 years ago |
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A: How to determine one's position in space? First off, plus/minus a few billion kilometers in any direction actually isn't that terrible, particularly if you have FTL and/or are already dealing with interstellar distances. For comparison, that is on the same order as the distance from the Sun to Neptune (Neptune's semi-major axis, the diameter... (more) |
— | about 8 years ago |
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A: How would lighthouses work in space? 1 - Is this system viable ? I think the buck stops here, really. No, it's not viable. What you are proposing is perhaps "possible" in some limited sense (but as already pointed out by others, you are up against some very fierce competition in terms of light sources). It isn't however viable. T... (more) |
— | about 8 years ago |
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A: How small can an organism get? 50 nanometers is awfully small. In fact, this is on the same order as many viruses, which can be 20-300 nm in size; to a first order approximation, this figure seems a good fit for Cort Ammon's estimate of 16-18 nm DNA strands. Some viruses are smaller along one dimension, but larger along others; Wi... (more) |
— | about 8 years ago |
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A: Space exploration is awesome, but why pay for it? You say that you want "present-day technology at the start of the super-spending spree". I'm going to take this to mean basically our current world. Wikipedia has a pretty decent article on the economy of the United States. It more or less starts out by stating that The United States' GDP was es... (more) |
— | over 8 years ago |
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How much land area do my land-based animals (herbivores) need for food? I'm trying to work out the kinks of an ecosystem on a planet that is rather similar to Earth, but with some species of animal (both carnivores and herbivores) we aren't familiar with in our world. The particular species I'm working with right now are purely land-based creatures. I've been able to us... (more) |
— | over 8 years ago |
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A: Volcanic Debris Clouds In Planet's Low Orbit? I think you are pushing the boundary of believability a little too far, at least for someone who is somewhat familiar with orbital mechanics. (That may or may not be a problem for your intended audience.) Space isn't high up, like: Space is fast, like: Now, in principle, you could get around t... (more) |
— | over 8 years ago |
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A: Where would fauns/satyrs fit on a taxonomic tree? This is perhaps not exactly the answer you are looking for, but I would suggest you consider the possibility of having the satyrs coevolve with your homids, but start from some other species. Humans evolved from apes; why can't your satyrs start from hooved animals instead? You already mention horses... (more) |
— | over 8 years ago |
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A: Why not build a space elevator starting from the moon? Problem? Well, I think you stated the problem pretty well already in your question. As the earth does its daily rotation and the moon does its monthly orbit the cable drags around, flicking over mountains and knocking over buildings. and Everyone within 30.12 degrees of the equator ...... (more) |
— | over 8 years ago |
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A: Can we start a colony on a passing rogue planet? Like other answers so far, I don't think that we have any chance of establishing a colony on that planet. I would like to add another reason, however, for why this is not possible with current technology. You state that the planet is a year away and moving at 50 km/s at a right angle to the solar sy... (more) |
— | over 8 years ago |
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A: Realistic Horse-sized Dog Breeds Realistically, a well-trained backpacking dog can carry up to anywhere between 30% and 50% of its weight on its back. While the dog's spine is possibly going to be a problem, that can be worked around with a suitably designed mount, so isn't the showstopper. People regularly take dogs backpacking wit... (more) |
— | over 8 years ago |
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Does intelligence necessarily lead to an abstract language? Pretty much what it says in the question title. Suppose a non-human, social species of Earth animal found itself on an evolutionary path that favored increased intelligence of a kind not completely dissimilar from that of humans. These creatures, from the beginning, are able to plan ahead and at le... (more) |
— | over 8 years ago |
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How would relatively cheap and abundant (but not free or limitless) electrical energy at an up-front cost impact society? A group of scientists has been slaving away largely in obscurity for two decades, with very few publishable results. Suddenly, one of them has an epiphany, which turns out to be instrumental to enabling them to succeed at what they are attempting to do. This happens around year 2020 or so, on Earth, ... (more) |
— | over 8 years ago |
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A: What is the best apex predator to thin the zombie herds? As you point out, any large predator should be plenty able to kill a human, given a reason to do it. Hunting for food could certainly be one such reason. Tigers already kill humans directly, and according to Wikipedia (cited), tigers cause more human deaths through direct attack than any other w... (more) |
— | over 8 years ago |
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What would the Earth eventually look like, if it was somehow stripped of its atmosphere today? Consider the present day Earth. Now, through some event (magic, a giant maid with a vacuum cleaner, a disgruntled alien did it, ...), our planet is stripped of its atmosphere. Assume that this happens in such a way that other features of our planet are not significantly affected, and that the Earth i... (more) |
— | over 8 years ago |
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A: Is there a reason to believe that programming languages are going to converge? Is there a reason to believe that programming languages are going to converge into a single language in the decades/centuries to come? As a programmer myself, I certainly would hope not. It would likely be a massive inconvenience for virtually everyone, and benefit practically noone. Different ... (more) |
— | almost 9 years ago |
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A: How would a government prevent astronauts from making political statements? Based on the fact that a habit spread among the astronauts to make political statements upon landing on a new celestial body, often the statements not pleasant to their government... (One way this could happen might be if a large fraction of the astronaut corps internationally move from being employe... (more) |
— | almost 9 years ago |
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A: What are the effects of a planet staying long-term inside of a nebula? Like Samuel mentioned in a comment, the effects would be minor to slim at most, and probably not detectable except from a significant distance. Nebulae are extremely sparse. Wikipedia states that most nebulae are far less dense than any vacuum created in an Earthen environment - a nebular cloud ... (more) |
— | about 9 years ago |
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A: You've made it to another star! Now, how do you find its planets? You could quite easily detect the presence of any planets by taking an image of the sky in a specific direction, move some small distance, and take another image of the sky in the same direction. There is no need to move to the opposite end of the system for this (as suggested by Darth Wedgius); movi... (more) |
— | about 9 years ago |
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What evolutionary factors can contribute to large sexual dimorphism in large mammals? On Earth, the polar bear is among the most sexually dimorphic animals, with males being on average almost twice as heavy as females (Wikipedia claims average weights of 450 kg for males versus 260 kg for females, with a significantly larger difference in the extreme cases). There is an obvious natur... (more) |
— | about 9 years ago |
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What would the sky look like to a being inside the event horizon of a black hole? Suppose it was possible to travel to inside the event horizon of a black hole safely. Also suppose said black hole is large enough that the curvature of the horizon of the surface of the central mass of the black hole is similar to that on Earth or perhaps the Moon, yet we are somehow able to hand-wa... (more) |
— | about 9 years ago |
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A: Information Exchange In Space Actually, even with contemporary communication protocols today, latency is not really an issue as long as the link is reasonably reliable. This is a delay-tolerant network. Note that in the real world, with long-range communications you are going to have to add a good chunk of forward error correctio... (more) |
— | about 9 years ago |
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A: Scale down the Solar system according to Earth The first thing that would happen is that it would wreak havoc with every orbit in the solar system. The orbits of the planets around the sun have their focal point very close to the sun's centre because the sun is so very much more massive than anything else in the solar system. In a binary system... (more) |
— | about 9 years ago |
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How can I destroy a gas giant planet? We have already discussed how difficult it would be to blow up a planet like Earth, basically deciding that you can't do that with any reasonable amounts of energy. But what if I don't need to blow up the planet (as in, cause a mostly-solids-to-near-solids planet to fragment), but rather want to just... (more) |
— | about 9 years ago |
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A: How would humanity enter a Dark Age? I haven't read through all the answers in detail, but there is one obvious possibility that I don't see anyone else having really mentioned so far: peak oil. Or more generally, peak available resources. First a bit of background. "Peak oil" refers to the moment in time when oil production (or extrac... (more) |
— | over 9 years ago |
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How can I make a net beneficial genetic trait occur only in a small fraction of the population, sustained? For a species I am working on, there is a specific genetic trait that I want to introduce into the population. The exact nature of either is not important for the purposes of this question, but the trait is of such a nature that it is visible in the individual's phenotype to others of the species and... (more) |
— | over 9 years ago |
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A: Gravity of an ancient Mars Gravity is not dependent on the composition of the body. In fact, Jupiter exerts exactly the same gravitational influence that a solid body of the same mass would. So does the Sun, or a black hole. The gravitational accelleration between two bodies for point masses can be simplified as $$ g = -\frac... (more) |
— | over 9 years ago |
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A: What is a reasonable amount of population growth for 900 years? Others have looked at this from various theoretical points of view. I want to look at it from the point of view of our own Earth's history, and what would be the impact if your population followed the same growth rate seen on Earth. Do note that for the purposes of this answer, I am ignoring the mini... (more) |
— | over 9 years ago |
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A: Does the sun being blocked affect electricity? Atmospheric dust by itself shouldn't have any major impact on generation or distribution of electricity. The two are unrelated. However, a fraction of the Earth's electricity production is based on current solar input, either directly or indirectly. There is the obvious: photovoltaic electricity pro... (more) |
— | over 9 years ago |
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A: How large does a spacecraft need to be to be visible from the surface of the Earth at 400 km altitude? The angular resolution of the naked human eye is approximately one arc minute, or 1/60th of a degree. (Also a nice illustration of what this means in practice, which just so it happens also shows the ISS for scale.) This is going to be different for different people, but should serve as a baseline (a... (more) |
— | over 9 years ago |
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How does animal size affect individuals' agility and speed? This question is a bit of an outgrowth of Can you simply scale up animals?, but it does approach it from a different angle. "All else equal" (which it of course never is, but we're good at pretending here, so let's pretend), heavier animals tend to be less agile than their smaller counterparts. This... (more) |
— | over 9 years ago |
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A: Asteroid impact. How big does it have to be to globally affect plate tectonics? I'm going to talk about Earth below, but since you say "an Earth-like planet", consider that just an space-saving measure. Take an Earth-like planet, about the same size, composition and gravity. ... Huge (say 500 kilometer diameter) asteroid strikes. Well, as it's said in the movie... (more) |
— | over 9 years ago |
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Can whiteout/snowstorm conditions be coupled with heavy fog? In a story I am working on, I need a scene in which one of the main characters finds himself outside in precarious weather conditions, unable to see unaided much farther out than an armlength or so. For the purposes of this question the setting is essentially our Earth, and my draft geographical loc... (more) |
— | over 9 years ago |
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Could venoms evolve naturally in mammals? Venoms have evolved in certain classes of animals on Earth (notably snakes and frogs, but also fish and maybe elsewhere that I can't think of right now), sometimes for defense and sometimes (particularly in snakes) for offense or hunting. Assuming an evolutionary process, could venoms similarly evol... (more) |
— | over 9 years ago |