I really want to bring this to the attention of almost every Science fiction writer, film script writer and comic book writer. There will not be nor never be spacecraft that will look like boats or planes. Space shuttle a exception that I hope will never be repeated. First think which way the ship goes accelerates. That is the way gravity will go, and if you had long corridors they would suddenly turn into very high ledges. Artificial gravity requires large deposits of handwavium and unobtainium. second space is not freezing cold. It has no temperature and you will actually overheat because it's a amazing insulator. heat is the enemy to any ship in space and when firing weapons you can literally be fired from the heat dump. Third there is no stealth in space. Space is mostly empty so any energy given off in any spectrum shows up like a light in a pitch black room. The most realistic space fighters in film are Babylon 5's starfury. there is no air to turn in so you can just rotate to take out a enemy from behind. I pulled a lot of this from Atomic Rockets which is a invaluable resource for any writer of Sci-fi that requires a spaceship. http://www.projectrho.com/public_html/rocket/index.php There are many things that realistic space travel brings to the table though. Rick's law: anything traveling at 3 km/s has the kinetic energy equivalent to it's weight in TNT. Be it a warhead or a pillow. This goes up exponentially with speed. At close to light speed a slug of steel becomes Even though there isn't stealth in space it's impossible to tell when your enemy is firing a laser at you. Light speed being the fastest anything can go. less than light speed can still move unpredictably which means space battles become like a mixture of weather forecasting, speed chess, and poker.
Some of these things look wrong to me, but I'm no science expert. For example, space definitely has a temperature. I know that much.
I don't write space battles, but I think The Universe documentary series had an episode on space wars which was pretty interesting. And yeah, there's a reason why shuttles and stations and EVA suits tend to be white. It can get really cold or really hot in space.
Mmmm... I see where you are going with this, but the "gravity" of which you speak would last only as long as the acceleration itself lasts. Once the ship has attained a given speed and maintains it, you're in free-fall. Just like when you're in a car: When you step on the gas and go, you feel pressed into the back of your seat, but once you're up to speed, you don't continue to feel pressed and you are free to drink your drink without the soda trying to creep up over the rim of the cup and race to the back of the car. Star Trek artificial gravity is of course bullshit, but simple centripetal force within a rotating part of the ship will give you an effect that the human body is not able to differentiate from actual gravity. But in all, yeah, there are lots of things wrong with a lot of sci-fi spaceship science. The parts that always stand out glaringly to me personally is the complete lack of thought for economics. Never mind magic gravity, how about the magic money that science fiction always comes up with to create spectacular things. In today's real world of science, each drop of water (actual individual drop) costs $10 to get to any current orbiting space station.
Hi, you've posted some interesting thoughts. Perhaps I can elaborate on a couple of them though. People do tend to think space craft need to look like the rockets we use to launch through the atmosphere and against gravity. Satellites can have all sorts of shapes and odd protrusions because there is no air resistance. In my story the ships were constructed in space and are very large. Once accelerated, they need very little fuel to keep up their forward momentum. I don't know what you mean here. No, it requires centrifugal force. But clearly this is not how most sci-fi stories handle it. Close but no cigar. Because of the lack of molecules in space the temperature is near zero Kelvin. However, space is not a perfect vacuum, there are actually lots of particles, it's just that space is so large they are far apart. Except where the Sun is shining, it is very cold. On the planet Mars, with a distant Sun and thin atmosphere it can be 60F at the surface and 100F below 6 inches up. As for the insulating properties of a vacuum, that one made me think so I decided the safest thing to do would be to look it up. I'll get back to you and the rest of the post in a minute. Got to go let the dogs in.
Only because it isn't a perfect vacuum. For most practical purposes, it really doesn't have a temperature. The rate at which a vessel absorbs and radiates energy is vitally important, and that depends on incoming radiation (including visible light), and blackbody radiation from the vessel based on ITS temperature. The average kinetic energy of the few molecules or atoms in a volume of space determine the actual temperature of that volume, byt the heat capacity is extraordinarily low.
Back to the insulating properties of a vacuum. Here's a better explanation of 'no temperature in space' I think you were getting at. http://www.universetoday.com/77070/how-cold-is-space/ Since we are usually talking about the astronauts and the space ships, they would lose heat very fast in space despite the insulating properties. Then there is this interesting trivia: That's addressed above, the sunny side cooks while the dark side freezes. All space ships should have heat exchangers. Think of the possibilities writers rarely exploit with that one. The ship could be melting on one side and freezing on the other if rotation of the heat exchangers fail. I don't know what you mean by stealth in this context. Space battles in the movies never get it right, things explode with sound that wouldn't occur, and there are fireballs where there is usually not the oxygen to burn. The particles from the explosion would travel at incredible speeds and wouldn't stop, posing a risk to everyone good or evil. And asteroids are always shown in close batches. Even in the asteroid belt the asteroids are very far apart.
Firefly was one of the better ones. The exterior shot during battles were silent, but they did still show energy beams cutting across the vacuum. You might see a laser from the side as it passes through a debris fog issuing from a hull, but you;d never see it in vacuum. The first you'd know of a laser aimed at you would be as i swept across your hull or caused space dust to sparkle.
One thing that bothers me about science fiction movies is walkways that have no handrails, especially where there is height that would clearly cause a fatality should someone fall. Is there to be no Health & Safety in the future? (I bet they only called it "The Death Star" because of all the fatal accidents).
OP, you do make a few interesting points. However, and I'm not trying to be rude, you clearly have a very limited understanding about space. Especially gravity and temperature. Gravity does not go in a direction, there is no direction in space. Up, down, left and right only apply when you are speaking in reference to something else. Gravity pulls things down on Earth because the core of the Earth is the center of gravity on this planet in relation to the center of gravity in our solar system. The core of the Earth is down for us, thus why we fall down. Everything heavier than air would be submissive to that gravitational pull. Balloons float up because helium is lighter than air. We are pulled down because we are opposing that gravitational force. You could easily have long corridors. Gravitational pull doesn't disable you from being able to climb through these corridors via some sort of suspension system. Like a rope and pulley. How strong the rope, pulley or individual pulling has to be is the only thing that is relative to the force of gravity. Also, long corridors would work fine if the crew creating the craft weren't ignorant of the nature of space. They could just orient it so that it would be more practical. Also, temperature. Temperature does exist in space. How does the heat from the sun reach the Earth if there is no heat in space? Like light, heat travels through space to reach its destination. It takes eight minutes for the light and heat of the sun to get to Earth. So, if it is traveling... and it isn't yet on Earth... then it is in space. Plus, if we want to be technical, we are in space right now. We only appear to be apart from it because of our atmosphere. If heat exists here, it can exist elsewhere in space. Space is freezing cold. Where there are no nearby stars, it is cold. This is why planets further from the sun are colder than planets closer to the sun. This is why, according to thermodynamics, space will eventually be even colder than it is. Space is still expanding and, eventually, it will expand so far that there will be no light or heat sources for light years around. It will be a big void that is really cold. Cold is the neutral point. Something cannot be without temperature. It's like darkness. Everything is dark until you add a light source. Everything is cold until you add a heat source. Of course there could be stealth in space. The ship with the most efficient power source would be likely to also have the least visible path. You say that a ship in space would light up like a light in a dark room. You seem to have discounted the casting of shadows by massive objects. Moons, planets, asteroids, all of these things cast shadows. Hiding behind any of these objects would be stealth. Otherwise, we have technology on Earth already which essentially mirrors the surroundings. If space is pitch black, a ship could appear pitch black. However, the usage of this technology does require the usage of light, which isn't as abundant in space. But, imagine how stealthy a ship could be in space if they were settled near something that light was hitting. Like an asteroid, planet or star. If you can see it, a light source is hitting it. So, your absolute assessment that stealth can't take place in space... doesn't stand up to reason. My last point is my most important one. It is called Science Fiction for a good reason. It's fiction. If the conditions of a fictional Universe allow for shots to be fired in space, then you can't really be upset. If this takes place in your own Universe with the understanding that it is not parallel or different in any way other than the fictional story, then you can be upset. If the condition of a story is that a boat can't fly through space, then it can fly through space. If that boat is flying through space in YOUR Universe, then that's when they have to start explaining things. "Logic will get you from A to B. Imagination will take you everywhere" -- Albert Einstein Never discount the ingenuity of thinking beings, you have no idea what could be and could never be. Only time can tell that story and she isn't speaking.
I think the point about the temperature of space is that since space is so close to a vacuum that makes no odds, there is essentially nothing there to have a temperature. Yes, if you have a 'thing' then that thing must have a temperature. But a vacuum is not a thing. The more an author strays too from plausible science the more the work becomes fantasy.
I'm sorry, but your own arguments show more misconceptions than the original post. True gravity is a property of mass, or more accurately, the way mass influences the geometry of space. "Down" is generally toward the nearest large mass, in simple situations. But the original post was talking about the illusion of gravity due to acceleration. On the Earth's surface, gravity is perceived as a force accelerating any object toward the center pf mass of the planet, a force roughly proportional to the mass of the object. This is doubletalk. It's true that we experience the gravity due to all the mass of the solar system inside the radius of the Earth's orbit, in the form of tides. Likewise, we experience the gravitational force due to the Moon's mass. The mass outside the Earth's orbit does contribute to the pull toward he Sun, for reasons I won't go into here (mathematics of inverse square fields). The center of mass of the Earth (again, from points at lesser radius than the point you are measuring gravity at) is the mathematical point that defines "down", but it isn't the core of the Earth that exerts the pull. This is not how it works. Energy in the form of electromagnetic radiation travels through space, but it is not heat until it interacts with matter and converts the electromagnetic energy to thermal energy. Thermal energy takes the form of molecular motion. Without particles of matter to carry kinetic energy, there is no therma energy, no heat, no temperature. Strictly speaking, there are gas molecules in space, but so few and far apart that the temperature is nearly undetectable. Objects IN space have a temperature. They will lose heat, as it radiates away as electromagnetic energy, with a frequency distribution dependent on the temperature of the object, This is what is known as black body radiation. The object will gain heat energy as electromagnetic energy from external sources is absorbed (and not reflected). If the rate of loss of heat energy is greater than the rate of absorption (ignoring internal energy sources) the perception will be that space is cold. If the influx of energy is higher, space will be perceived as warm or hot. but space itself does not have a temperature. Only the matter has temperature.
Well, space itself has no temp. It's the particles that are carrying the energy. I think if they wanted to evacuate heat from inside a ship, they would need some form of dumpable heatsink. They use water in nuclear reactors to transfer heat, so for starships, at stopping points, it could dump off heated water and refill with cold.
To the OP, you're limiting it to hard science fiction. Science Fiction is the top-level genre, then there are various sub-genres, such as hard science fiction, which you're advocating, and Space Opera (Star Trek, Star Wars, etc). All are valid science fictions because the operative word is "fiction." "2001" is no more true than "Star Wars." "2001" uses plausible ideas, but it's no more a real event than is "Alien."
Perhaps we are thinking of different things but the temperature of an object in a vacuum still dissipates by thermal radiation. One doesn't need a heat sink just because one is in a vacuum. http://en.wikipedia.org/wiki/Thermal_radiation
The photons emitted as a result of the radiation are particles. "A photon is an elementary particle, the quantum of light and all other forms of electromagnetic radiation, and the force carrier for the electromagnetic force, even when static via virtual photons." Anything with a temperature above absolute zero is emitting em radiation and therefore, light in the form of particles called photons.
I understand photons and the EM spectrum. I was addressing your heat sink. Why would you need a heat sink to send radiant heat out into space?
Because radiation is the slowest means of transferring heat. The ISS and shuttles have internal cooling systems because they can't evacuate the heat fast enough by mere radiation.
@Cogito Oops, looks like I might not know what I'm talking about after all. Yikes. Was going to try to counter, but I found myself clawing around for technicalities. You understand this better than I do, I'm not a scientist. More to learn, then. Sorry!
I don't have much time to respond, but I am really happy to get responses and great questions! I first want to say that a badly grounded Sci-Fi grates and relies heavily of the star wars, star trek and other worn out tropes. Using a grounded space opera around the solar system has a lot of potential for being original. The solar system has a lot of places to go besides planets http://www.asterank.com/3d/ remind yourself the blue do is us. In space it's not just the outside heat but also the heat of everything on the ship. here is the equation ripped from atomic rockets page ∂Q/∂t = Re * (5.67x10e-8) * Ra * Rt4 where ∂Q/∂t = amount of waste heat to get rid of (watts) 5.67x10e-8 = Stefan's Constant Re = emissivity of radiator (theoretical maximum is 1.0) Ra = area of radiator (m2) Rt = temperature of radiator (degrees K) let's say the ship runs at 15 megawatts and this is on the low side of a decently large star ship. 5 megawatts is directly converted in to thrust by Ion engine which is unrealistic but you get the idea. 10,000,000 watts = .95*(5.67*10^-8)*area*temprature if I put in 700 kelvin (427 Celsius) for the heat radiators. You still need 773 square meters of heat radiators to take out 10 megawatts or what a small industrial generator makes. This would be in pitch black of space. Not in the sun which would make it worse.
Very interesting and stimulating thread. All the contributions make good points—even the ones that may not be totally accurate. This is why I love reading Sci-Fi, and why I would NEVER attempt to write any! My brain is not wired for equations. (I'll stick to history instead, and try to learn from that....) One idea in particular intrigues me. It's the design of space ships—the big ones, not shuttles which do enter and leave atmosphere. I take it the ones that stay in space don't need to be aerodynamic at all, because they won't be encountering any "aer?" So does this mean they can be any shape at all? I presume if that's the case then it would make sense to construct them to mimic a place that does have gravity ...like earth. Round, then? With a rotational core, to create the gravity? And maybe the ability to rotate externally—automatically—to keep and lose heat as needed? Where would the pilot and crew be located on this behemoth? I suppose with all the electronic gadgetry in play, they could technically be anywhere on the ship. But I think it's in my nature to want to see where I'm going, so I'd definitely want real windows facing forward.
One has to switch concepts of up and down. Spaceships like Star Trek have these flat things with people on different levels. But a large rotating vessel, circular, with 'down' being the outer wall of the rotating ring makes more sense. Each level would be the rings inside of rings. The inner rings would rotate at different speeds to equalize the centrifugal force on each level. The location of pilots, crew, again, think function in space. One would navigate via instruments. The pilot need not be in amy special place, or perhaps the location might be related to the driving mechanisms, or deep inside where it is more protected should any part of the outer shell fail. Just some ideas.
I just saw Alien again, and realized that I'd forgotten about the ugly and utterly un-aerodynamic shape of the refinery that was being towed by the Nostromo. It traveled through space without looking the least bit like a vehicle.
@GingerCoffee I love you for using sources. In threads like this, people say all kinds of things, and if they don't refer to any outside sources, it's difficult to see what's accurate, or as close to accurate as possible, and which come down to semantics. It helps to evaluate the information provided. Hard sci-fi can sometimes be inconvenient, so I'm not surprised novels and books turn to the fantastic at times. Personally, I like the illusion of "hard", but that there are also familiar elements. I want the story to be first and foremost about the characters. Anybody can jot down a wealth of facts, but to make the story come alive is another thing. Even shows like Battlestar Galactica employed scientists as advisors, yet there are still plenty of fiction-y elements.
If we take a look at where we actually are in the space-exploring scale, we could label everything (even the "hard facts") as fantasy. Everything we know about space is guess and theory, we can make wild guesses, and scientists will make educated guesses. Tesla said: "One day man will connect his apparatus to the very wheelwork of the universe... and the very forces that motivate the planets in their orbits and cause them to rotate will rotate his own machinery." Place a story in that evolutionary period, and you can make the ships look like elephants, dye them pink and it will still be sci-fi. Also, Clark's third law: Any sufficiently advanced technology is indistinguishable from magic. Zelazny literally showed that in "Lord of light" and "Creatures of light and darkness" Regarding space, nothing is impossible, it can only be improbable, but improbable is still possible, and it can still be sci-fi, and it can go higher in plausibility scale than your average space-opera. Nothing wrong with them btw
