New answers tagged

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If a cylindrical rocket ship with a diameter of about 350 meters were spinning on its long axis, would more than just the interior surface of the outer hull have artificial gravity? Yes. Any interior walls parallel to the outer hull would also have apparent gravity, proportional to their distance from the axis. If there is any loose material inside, though,...


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Antimatter will almost certainly not replace fusion because the fuel is simply too expensive to synthesize despite the efficiency. What is probably a better idea is antimatter induced fusion, if fusion power is too hard to make work otherwise. While antimatter is 259 times as efficient as Detuerium-Helium-3, and while antimatter rockets have a theoretical ...


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Nuclear fission rocket is becoming obsolete and is superseded by the more efficient antimatter engine, in fact there will be no pollution and the efficiency is around 100%. Unfortunately no. Firstly, you can you create your antimatter. The pesky law of conservation of baryon number means that in most cases your maximum efficiency of antimatter creation ...


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Check this link for a fusion-powered spaceship that could be ready in the next decade. The Direct Fusion Drive (DFD) engine could take flight for the first time in 2028 or so. The minivan-size DFD could get a 10,000 kilogram robotic spacecraft to Saturn in just two years, or all the way out to Pluto within five years of launch. Such a spacecraft would be a ...


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A space propulsion system doesn't have an efficiency, it has a certain amount of thrust, and it can produce a certain amount of deltaV, and for a fixed power level you can trade of deltaV for more thrust. This means even with antimatter powered spacecraft, you can still build defensive nuclear craft that may not match them in operational range, but can ...


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(A couple options -- feel free to use either or both!) Stability Antimatter is really finicky about how it's contained. High-G combat maneuvers and delicate magnetic bottles are not friends, and even a minor bit of battle damage to the bottle is an all-but-guaranteed loss of ship with all hands. Fission is much easier to keep stable in combat, and ...


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In wartime, quantity is a quality of its own. You do not need ideal weapon during war time. You just need more of it than your enemy. Given that: Fission fuel is easier to obtain than antimatter as you can dig it on homeworld or other celestial bodies There is no natural antimatter source, at sufficient quantity, in solar system Fission fuel is easier/...


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Yes, I think that there might be no nuclear fission powered ships, but nuclear fusion ships will still be there. Or maybe there will be hybrid ships that can run on fusion or annihilation. The reasons: There are no known natural occurrences of antimatter (at least not in amounts that could be useful for spaceships), so you can't harvest antimatter, but ...


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Well, someone during WW2 used bow and a claymore John Malcolm Thorpe Fleming Churchill, DSO & Bar, MC & Bar (16 September 1906 – 8 March 1996), was a British Army officer who fought in the Second World War with a longbow, bagpipes, and a Scottish broadsword. Nicknamed "Fighting Jack Churchill" and "Mad Jack", he was known for the motto: "Any ...


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In any reasonable situation, the trip is absolutely pointless in the extreme. Totally counterproductive, even directly harmful. At 0.999 light speed, the gamma factor is 22.37. That means, in order to accelerate a mass to 0.999 light speed you must expend an energy 21.37 times the mass-energy equivalent. That is, you would need to expend grotesquely more ...


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If you are flexible on the shielding materials, this trip is no problem. While concrete and lead are effective shielding, so too is water. Within just a few meters, the radiation from spent fuel rods can be rendered effectively harmless. For the kinds of radiation coming off spent nuclear fuel, every 7 centimeters of water cuts the amount of radiation ...


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James' answer is fundamentally correct. On top of that, consider that with time contraction you also have time dilation, so for an external observer the time between nuclear decays will be longer, thus the radioactive fuel will be less radioactive, "magically" matching the shorter shielding.


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Length contraction, like time dilation, is only seen by outside observers. To the crew, their spaceship & cargo, and their perception of time, will appear unchanged. It's only the outside universe that will look weird. So to the crew, the cargo will always appear to be at the end of a tether that's 10,000 mm* long. *Did you really mean 10,000 ...


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Phil Geusz's David Birkenhead series has one of these that works. The background is that there's a civil war in an interplanetary empire, and this planet was planning to switch from the loyalists to the rebels. The loyalists arrived first and prevented the betrayal, so the rebels arrive to find a planet against them instead of for them. The rebels have to ...


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Internet is full of calculators if one searches for them. From atomic bomb to asteroid impacts, people can calculate anything. Spinning worlds included. Here is just the first of the list I found by googling. For a 2.5 km radius you get an angular velocity of 0.59 revolution per minute. For a 1.5 km radius you get 0.77 rotation per minute.


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TL;DR Well, the thing is, you can't invade earth, as we have enough firepower to blast any fleet that comes withing range.* Therefore, your aliens must consider alternative options. A viable strategy for them would be to show up in orbit with a mock-up of the Death Star in tow. Long answer: While it would be very easy to get ships to a planet you want to ...


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Zero, since no light source has been specified, and those are pretty darn advanced. However, assuming earth-like lighting, we can leverage Biosphere 2 as our one data point, as it is the only real attempt at a sealed biome for humans. It was 3.14 acres and housed eight people. One of your tubes has roughly 750 acres of space (assuming you don't try to ...


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The need for space survival is only coincidental It's not that your passengers need to survive actual space, it's just that conditions inside an ftl ship are harsh in ways that are similar to being naked in space. One theoretical method of ftl travel is the alcubierre drive which has been theorized, if it could be built, would expose the passengers of the ...


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A network of "gates" that scan content and only send living beings. You could use as your FTL system something analogous to the Stargate network: a series of devices at different locations, built using inscrutible technology by an advanced (extinct? ascended?) alien species, which can transport living beings to other devices in the network near-instaneously....


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FTL travel requires entering a hyperspace-like state, in which, though lightspeed is still a limiting factor, distances between corresponding points are greatly reduced -- for instance, to reach Alpha Centauri from Sol via hyperspace may be a journey of only a few kilometers, easily managed in minutes with fairly basic methods. The catch is that, in ...


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Let's make your planets more complicated: Each one is a hollow sphere, but with a sphere of inside it. Think tennis ball inside a softball, but probably closer in size. The shell then has the job of contain the atmosphere. This allows you do do some cool things: The visual distance in air at sea level pressure is 50-100 miles max. So if the space ...


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So the short answer is that any hollowed out object no matter how big will have zero gravity on the inside (even with an atmosphere on the inside). And no matter how distant the two structures are, over a LONG period of time, they will eventually impact each other. Thanks for you help.


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1. It depends upon the the contents of the structure, but the shell will not exert any net force on objects inside. but as you go down towards the centre the gravitational force would decrease proportionaly. 2. If the bodies are stationary with respect to each other then there is no safe distance, it would just be a matter of time. That could even be ...


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The people inside each hollow Earth will experience no gravity. This is due to the Shell Theorem. A non-hollow planet does not suffer this effect. In simple terms: in a non-hollow planet, as long as you are not on the mass center, there is always more mass pulling you to the mass center than otherwise. On a hollow, symmetrical planet, if you calculate the ...


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You are talking about planets that are near each other somehow, so I'm going to draw your attention to this concept. A roche limit is the distance within which a celestial body, held together only by its own force of gravity, will disintegrate due to a second celestial body's tidal forces exceeding the first body's gravitational self-attraction. There's ...


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According to the Shell Theorem, a spherically symmetric hollow sphere will always have zero gravity inside, so the people experience no gravity at all, unless they live on the outside or within the shell itself (where gravity will linearly fall off going inside). On the outside, gravity will be far below earth normal, because a hollow sphere of earth mass ...


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Reality check, if you can create worm holes anywhere. What do you need a laser for? Just create a wormhole that links from a black hole or star gravity somewhere, and put the other end inside the thing you want to destroy. A laser is a waste of energy if you can already create worm holes. And that episode in particular was pretty inconsistent and had the ...


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Wormholes aren't forbidden by relativity, which isn't quite the same as "scientifically plausible". If you were able to make a wormhole, then you'd be able to pump energy into one end and get energy out of the other end. Exactly what comes out of the other end rather depends on the nature of the wormhole metric. Given that wormholes may be mathematically ...


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Another approach would be to look at the current theories of "realistic" teleportation. They basically amount to the belief that it isn't viable to actually transmit matter like a Star Trek teleport, instead teleportation would work by mapping a body, killing you and then effectively printing a new copy wherever you want to be. At which point the speed you'...


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If whatever FTL trick you're using affected the inside of the ship, it wouldn't be very healthy for the crew. It's not just teleportation. Imagine you are walking forward or backward in the ship. What would happen to you if you could experience the warp speed you're travelling at? Obviously, any transport method used necessarily mustn't be felt inside the ...


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Try not to think about it too hard. It's not possible in this universe to go faster than the speed of light, it is irrational, so justifying how transporters will work in a rational way is also not possible. The answers you have here that say that it would make no difference are all completely wrong in RL btw. They are based on notions that only work at ...


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Warp 2, eh? Well, you're clearly using a warp drive, like some actually functional and practical descendant of Alcubierre's ideas. Such systems don't involve the ship travelling faster than light at all, but only the warp in space around it. That's why at sublight speeds the occupants of a ship using a reactionless space-warping drive don't experience any ...


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The real answer is "whatever you want." We have no known physics for what happens past the speed of light, so you are writing your own rules. However, if we are to use our own intuitive laws to try to write what happens faster than light, most of our laws of physics state that if every point that you care about is moving at the same pace, the laws of ...


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Energy consumption Blockchain is HUGELY energy intensive (it was estimated that Bitcoin's annual carbon emission is 20-22 Million Tonnes - which, if it were a nation would equal carbon emissions of Sri Lanka). Based on Moore's law, due to the increase of processing power, modern day cryptographic algorithms have to keep adding more bits to their moduli in ...


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Blockchain is only "secure" and "difficult to hack" when it's distributed over a lot of systems. The "truth" in a blockchain system is the truth most of the systems which calculate the blockchain agree on. So if you want to manipulate a blockchain, you need to hack over 50% of the systems to have the whole system assume a new truth and hack 100% to destroy ...


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Blockchain tech is about maintaining integrity across a distributed system, which is why it's used for decentralised transaction processing. Every node in the system has to agree on the history and what the definitive version of the blockchain is, which can be a pretty laborious task - one of the reasons Bitcoin's network has trouble processing the kind of ...


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In practice, the reason they don't use blockchain is the same reason they don't use vacuum tubes. By the time you're thinking in terms of military spaceships, blockchain will be some forgotten old reference only of interest to those studying the history of computing. Be very careful putting fine detail on the cutting edge of present technology in a future ...


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Blockchains only make sense when you need to ensure the integrity of, well, a chain. In the most general case, the way a blockchain works is that each block contains a data payload, and a verification hash, which is a fixed-size summary of The payload of this block, and The entirety of the preceding block. Because the hash of the preceding block was based ...


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Well, as a programmer, I can easily give you two reasons. First, it would be extremely difficult to modify data in the log. Say your hypothetical "Cpt. Kirk" gets pissed at the science officer (let's call him "Spock") while inebriated. He then puts an extremely ill-thought-out entry in our hypothetical log, saying some... ah... unprintable things about "...


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What evidence do you have that they do not? If blockchain protection becomes the standard way to protect and insure important documents and everybody has access to it and uses it as a matter of course, then it just wouldn't be mentioned by narrator or character. Just as you would usually not say that someone wrote "with a ballpoint pen", or wore "leather ...


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if I were these people I would go with organic computers and navigation devices. A brain for navigation, one for weapon systems and another for life support. there could be a master brain which coordinates all of them. All of these could be engineered from humans and used to control the ship. for weapon guidance systems you could use magnetism.


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Laser propulsion has another cool advantage, you don't even need ablator if you're in a planet with atmosphere. You can actually use a design that uses air as its propellant for what is effectively the first stage. Such a proposed design is called a lightcraft. This has a few major downsides. The first problem is that we have no idea how to build a laser ...


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Since you aren't requiring that your ship obey the prime directive, have its robots construct a mag-lev launch platform with a massive power source at the landing site. Mining and refining raw materials from the planet, the ship could create everything needed to throw itself back up to an altitude where its thrusters could be engaged safely. After the ship ...


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Good old-fashioned countermeasures. Mock up your radar, thermal, and gravimetric signature. Incoming missiles must throw dice to figure out which one isn't a decoy. Short-range warp engines that allow light-fighters to matrix-dodge projectiles. This consumes a lot of energy, so you would only use it when you absolutely need to. Energy-based shielding ...


0

Use an impulser engine. An impulser pushes off space-time, generating a ripple that carries equal and opposite momentum, therefore it doesn't violate Newton's laws of motion. (rule #4) Impulsers only require an electric power input (no propellant) - no mass is ejected from the ship. (rule #2) The amount of momentum imparted by the ripple is equivalent to ...


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Slap a basic impulser engine on it that pushes off the fabric of space-time. This means you don't need a propellant, and the only fuel you ever need is for the reactor or powerplant. The sci-fi "physics" principle behind an impulser is that it generates momentum with an equal and opposite ripple (wave) in space-time. Objects in the path of the wave will be ...


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I would envision typical sci-fi "blaster-like" energy weapons as producing unstable damaging particle blasts that decay over time. This decay produces low amounts of non-ionizing radiation as a byproduct, up to and including visible spectrum. The amount of radiation from the particle decay is far too weak to cause significant damage. Over time (and ...


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No space magic answer: Antimatter is probably the best place to start, considering it doesn't have a high activation energy. All you need is a magnetic containment system, then meter out enough of it to start a self-sufficient fusion reaction. Soft sci-fi answer: If you had something that can produce an energy field on the cheap that greatly decreases the ...


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The easiest defense against a laser would be spin induced artificial gravity. You move the affected part of the hull under the beam fast enough to prevent lasting damage or at least keep pulse lasers from drilling too deep. Think of a carbon foam as outer layer. Either it escapes the beam glowing and radiating the energy away but otherwise fine. Or the ...


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You need two things: a way to land without a prepared (long, very smooth) runway, and a way to return to space without refueling. An antigravity (or reactionless) drive is the simplest way to manage both of these. Even if it uses a huge amount of power, as long as it scales up well enough to transport a fusion power plant, the ship can be as big as it ...


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