Codraroll

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  1. Presumably, by making the rocket shorter.
  2. Or alternatively, use a helicopter. You didn't specify how far above a planet you should hover?
  3. Actually using superhuman strength with a human body has its limitations too. As @Streetwind said, lifting heavy things becomes complicated, because your puny body can only span a rather limited area of ground. If your center of mass moves outside the area spanned by your feet, you will fall over regardless of strength, unless your foot is somehow gripping the ground. And since you only have two feet, that area would always be long and narrow. No good if you're trying to lift, say, a concert piano without crawling underneath it first. To lift something big, you'd have to find its center of mass, get a handhold right underneath it, and lift straight up. Otherwise, you'd be throwing yourself off balance and falling over. But your grip on the object in question is a difficult matter too. Not all materials are rigid enough that they are practical to lift as they scale up. Imagine trying to lift a beached whale, for instance: You can lift up a small corner of blubber if you find a good handhold, but the rest of the whale would still sag and rest firmly on the ground. And if you tried to drag the poor whale by gripping its tail fin and pulling with your super strength, you'd be more likely to tear off a hand-sized chunk of the fin than to move the whale anywhere. Actually, due to the grip issue not even that would happen - you'd simply pull yourself towards the whale instead, as it is a lot more firmly anchored to the ground than you are. Now, not all heavy objects are whales, but even seemingly rigid objects behave somewhat like them on a larger scale. Try lifting a car by its side mirror, for instance, you'd just tear it off. Try pulling a Superman and lifting a plane with your bare hands - the plane's hull would just buckle around them. And lifting a building would be completely out of the question. Your average flimsy LEGO building is much, much more rigid relative to its size than a real-life building is. No matter how you gripped it, without carefully placed supporting structures you'd just tear off a chunk. If you try to lift very heavy things, you have to ensure that the piece you're gripping is solid enough to carry the entire weight of the object. A secondary ability that would be required for practical super strength is also super durability. For instance, say that you try to lift one of those cartoon weights of one ton lying on the floor in front of you. You'd probably tear your arms off before you got the weight off the ground. Pulling a tree out of the ground? Same story. That tree is a lot more firmly anchored to the ground than your arm is to your shoulder. You can't win that tug-of-war by strength alone. Of course, this assumes you manage to brace against something, otherwise you'd just pull yourself towards the object instead. Then for really heavy objects, you'd run into problems with the ground itself. If you somehow were to find the center of mass of an airliner, had a convenient and sturdy handhold to grip, and you were solid enough to handle the load, you still wouldn't be able to lift it over your head and walk down the road with it. Then the entire mass of that airliner would rest on your foot, which would be similar to balancing your entire weight on the point of a knife. You'd step right through the pavement and sink into the ground until the airliner came to rest on the surface. So yeah, with super strength you could probably be better at throwing things (although the recoil would knock you off your feet) and doing slightly more heavy taks than a regular human, but physics would limit how much your ability would scale up. Don't expect anybody to be able to hold back a jumbojet from taking off or lifting trucks over their head with one hand or anything like that.
  4. I was watching a video about satellite building when the thought struck me: How cheaply could you feasibly build a satellite? As the word has many definitions, let's consider a case: A satellite about the size of a washing machine, in low Earth orbit, with no functionality whatsoever except being visible to trackers (and the right type of telescope) and having your name engraved on it. Let's pretend you have a dream and much money to spare, but not that much money. Let's assume the cost of the launch itself is not a problem, but on manufacturing the satellite itself you want to cut as many corners as feasible. Could you feasibly weld something together in your own garage, be confident enough in your own craftsmanship to know it won't fall apart from the launch forces, hoist it onto your flatbed truck and haul it off to Cape Canaveral? Or would the launch companies refuse to have anything to do with anything that isn't accompanied by a stack of signed documentation from a certified and trusted supplier, included proof of assembly by certified and trusted personnel? And if you have to order your satellite from a manufacturer, how much would they charge you? Assume that your goal is to launch an intact satellite way above cubesat size, but it doesn't have to actually do anything once up there. There's no way for the satellite itself to stop working unless it physically breaks apart, and you're building it sturdy enough to know that it won't. Does it still have to, for instance, pass all those expensive radiation and temperature tests or be handled in clean-room conditions at all times?
  5. Or unless they take the Hot Fuzz approach, and shoot the mundane stuff with fast cuts and dramatic music. Seriously, that movie contains an ungodly amount of paperwork you barely notice because it's made to look cool.
  6. On the contrary, I don't think Interstellar does such a good job of portraying science either. At the beginning of the movie, the main character's son is told that he shouldn't study science, because society needs more farmers due to the ecosystem collapse. You know, a problem to be figured out through agriculture (not through agriculture research, just through growing more crops) and not by scientists. Society seems to tackle the problem of blights and crop failure with "well, this planet is screwed, time to find another one". Because I guess research into blight-resistant crops wouldn't help at all. I also seem to recall that the government had begun to promote conspiracy theories to discredit science and engineering, so that more people would go into farming jobs. The scene portrays science as both unable to solve problems, and an unnecessary pastime when a situation comes along to call for farmers. Later on, the infuriating scene on the planet deep in the black hole's gravity well. Before they descend to the surface, they tell each other "As we all know because we all have degrees in this sort of thing, the high gravity on the planet means one hour on the surface is like 25 years outside here." "Yes, when one hour passes down there, 25 years will have passed up here where I'm staying." "One hour there means 25 years here, got it." (and so on a few times - they repeat that "one hour = 25 years" thing for a while to make sure the audience really understands it). Then they arrive on that very surface to find out to their great surprise that the beacon that had kept sending emergency signals for 25 years was still active because... only one hour had passed on the surface! Who could have foreseen that! And then they go back up to rendezvous with the mothership, and are shocked to find the guy onboard to be 25 years older. It's also a plot point that massive tidal forces from the black hole would regularly send enormous tidal waves around the planet, but everybody fails to notice this before they land. In short, the entire scene portrays scientists as incompetent. And then at the very end, they throw science out the window and decide to show how feelings and intuitions are better tools for making decisions rather than assessing the facts, and it produces better results too! To put it in the words of this Cracked.com article: Cracked actually has another pair of articles about the stupid portrayal of science in movies that would be relevant to this thread. Read them, they're a delight.
  7. Funnily enough, I can't think of any straightforward examples that follow the entire recipe, but tell me you haven't heard this story before: Our hero, a retired military officer, is visited at his farm by his former superior ten years after he quit the military. The superior tells him that the Research Facility has found something they want him to have a look at. During an operation in (insert current war), a sudden incident happened out of nowhere and a whole platoon went missing. The last transmission heard from the platoon was a strange blip on the radar/noise/signal cut-out/sensor reading similar to what was observed in the classified incident back in (insert war that happened a decade or two earlier) where our pilot hero lost many of his men and which caused him to retire. Cue our hero saying "they're back" for the trailer. Our hero is taken to the Air Force/Space Force/Army Force/Underground Force/Navy Force base, stopping for a moment to admire a museum piece of an aircraft/spacecraft/car/boat/drill tank from his days in service on display outside the building. He's then taken straight into a briefing with a live link to soldiers in the field, going to see what happened to the platoon that went missing in the previous incident. He observes the scene for three seconds and asks one question, whereupon he scolds the general and scientists for making rookie mistakes, asking them at once to pull out the soldiers. Just as he does so, The Incident happens again and the link to the soldiers is lost. Our hero is given command of a team of special ops soldiers, and asked to investigate The Incident further. There's a scene in a big hangar-like laboratory where all sorts of generic science/manufacturing/equipment testing is performed at scattered tables out in the open. Here, the team is kitted out with the best and most advanced equipment government money can buy. As our hero gears up, he manages to break the fragile equipment by poking it with a finger, but easily wins a training exercise by relying on his instincts instead of the equipment. The scientists are all upset that he didn't use the equipment the way he was supposed to. Cue a quip about the equipment not being designed the way it was supposed to. The little platoon is sent out to encounter The Incident, in the best and newest aircraft/spacecraft/car/boat/drill tank available. Something mysterious happens that disables all the equipment and renders it useless, and after a thrilling action scene, our hero and a few of the soldiers barely escape with their lives. When they manage it back to base, they hear that The Incident is spreading, and the scientists have no idea what is happening. Fortunately, our hero has made an observation nobody else has, and he knows how to counter The Incident. The scientists are eager to equip him with the newest and best tech. Our hero refuses. The scientists insist, saying that "this is the best and most advanced piece of technology ever assembled." Cue something breaking spectacularly in the background, proving our hero right. Instead, the museum piece from the display outside the building is brought up on the runway, filled with fuel and obsolete ammunition, and our hero takes it to The Incident. The old equipment is immune to whatever disables the modern equipment. Our hero wins the day and saves the world. Anyway, while the story might be too clichéd to ever have been written in full, the sentiments linger in Hollywood screenwriting: Don't rely on anything modern, because it will always be useless. Trust your own experience instead of that of professionals - they are always wrong. The equipment used Back In Your Day is superior to anything that has been made since. Old technology will save us. The very newest generation of tech is likely to be outright evil. People in lab coats know nothing. Expertise is useless unless it comes from a guy without a formal education. One lone scientist may be right, but the entire scientific community is generally wrong. And of course, love conquers all. If the story is sci-fi, always expect the heroes to represent the old ways, the famers, the everyman, while the technologically advanced society is evil. The Empire furnishes their extravagant headquarters in polished metal and sleek iPod lines where not a speck of dust is visible. The resistance base is dirty, untidy, and full of outdated tech hobbled together with tape and wire. Small woodland creatures with sticks and stones will eventually defeat the tanks and lasers of the Empire. Sleek and modern = evil and decadent, old and used = salt of the Earth (at least up to a certain point - if the grime and wear extends to poor lightning as well as poor cleaning, it crosses over into being the lair of a serial killer). Star Wars is the prime example here, but you can see it in The Hunger Games or Pacific Rim too. The Jurassic Park series is basically all about how teeth and claws are better than guns and how science brings nothing but hubris. Same goes for the recent Planet of the Apes trilogy. I believe Battleship made a similar point about old vs. new technology, although I didn't watch it. In Armageddon, a bunch of oil drillers outsmart all of NASA for an operation in space. In Independence Day, a TV repair man creates a computer virus that destroys the alien mothership while the scientists at Area 51 are killed by the very thing they are supposed to have been studying for years. I'm a little annoyed with this "science is useless and technology is evil" narrative, to say the least.
  8. The more I think about it, the worse of an idea the 1g 10 ft diameter cylinder becomes. How would two people standing upright pass each other if one was going from one end of the ship to the other? One of them would have to walk up the wall relative to the other and crouch down, as there would only be five feet from the floor to the centerline at any point. Stepping out of the way while standing up is not possible, as everybody's torso would always be in the center of the tube. This, of course, ignores how incredibly uncomfortable it would be to walk around with your head experiencing constant negative Gs and the dizziness of the Coriolis force. This calculator cites some sources that say 10 RPM is more than even seasoned pilots can adapt to within a reasonable time frame, and your ship is doing 24.4 RPM. But that assumes walking up the wall is even possible. You can't dedicate the entire spacecraft interior to be a floor. Presumably, all sorts of instruments, controls, screens, etc. would line the walls of the tube (just see the ISS), so you can't just put your foot anywhere. By the way, due to the aforementioned issues with standing up, and a lack of space for anything that pokes into the tube, the only feasible position for working with any of these would be lying down next to them, which is not a comfortable position to hold for any length of time even if you're not spinning around once every 2.45 seconds. Then there's the storage compartments. For reasons mentioned above, they would have to be recessed in the floor. And since the spacecraft spins so quickly, the gravity at the bottom of these storage compartments would be quite a bit stronger than on their surface, so working inside them would be a royal pain. Half a meter down, you're at 1.3g already. Solar panels or radiators (30 people generate three kilowatts of power even at light activity, so you'll have quite a bit of waste heat to get rid of) sticking out five meters beyond that would experience 4.5g at their tips. It would make EVAs difficult, to say the least. And of course, space. Space for 30 people in a 10 ft wide tube, with provisions to last for half a year. Using the ISS as a very rough comparison, that one contains a pressurised volume of 900 m3 and has provisions for six crew for ... I can't find any sources on the fly, so let's say three months. Your ship has five times as many crew and they're up there for twice as long, but let's say they're all Commander Toughguys and live twice as cramped as the ISS crew does, cancelling out that last doubling. So a pressurized volume five times that of ISS, or around 4500 m3 would be required. Let's say 4000, because it makes calculations easier. Now, we've already assumed storage compartments to be half a meter deep, so let's say you have a pressurized radius of 2 meters. 4000 m3 / (pi * 2 m *2 m) gives a necessary tube length of (1000/pi) meters, or 318.3 meters. 1043 footsies if you want to stay Imperial. You can find contrived reasons for halving that number, and maybe halving it again, but your ship would still have proportions like a toothpick. This is just the crew and pressurized storage compartments, remember; presumably you've got a power plant and a propulsion system as well. The point I'm trying to make is, 10 ft is ludicrously small. Both for the size of the crew, the magnitude of gravity you're looking for, and for the technological advancement required to make it a reality in the first place. If you can outfit a ship for 30 people for six months, and mount a nuclear engine at its back, you can easily build it with a bigger diameter. Building it 4 meters wide and 300 meters long would be vastly more difficult than, say, 10 meters wide and 50 meters long (which gives the same volume). With the ship's floor once again being half a meter from the hull (at a radius of 4.5 meters), you can do 1G with a spin rate of 14 RPM, which is still a lot more than what is comfortable, but enough for a semi-realistic Commander Toughguy to overcome while his crew does not. And you can have upright workstations, and all the storage in zero G in the middle of the ship. Scaling up the radius makes everything more practical overall.
  9. [snip] And for the record: What kind of rocket are you thinking of here? 30 people in a ship with a diameter of only three meters? It would have to be a rather long tube, and the people would constantly walk into each other because the distance from head to floor is shorter than the distance from head to celing, or the distance from waist to wall, by a pretty considerable margin. How would you even duck out of somebody's way? Taking a step to the side wouldn't move your head away from the centerline of the ship. Heck, with a diameter that small, and rotary gravity, people's heads would constantly experience negative Gs because most people are more than 1.5 meters tall. So yeah, you're effectively stuffing a lot of people into a tiny corridor, and one would think the technology required for a spaceship to sustain 30 people on a long-term voyage to Mars would also produce rockets with slightly less cramped living quarters. Messy situation. If the woman was already pregnant when the ship launched, the fetuses probably wouldn't survive the launch itself. If she got herself pregnant during the voyage, there's effectively no good way for it to end. It's an ethics question first and foremost, not a science question. [snip]
  10. In the later Expanse books, railgun projectiles are said to fly at "an appreciable fraction of the speed of light", and one of the experienced engineers in the series does a double take when she looks up just how fast they go, so I think your estimate is off by a couple orders of magnitude at least. It sounds like several hundred kilometers per second is more like it. Just how the engineering of that checks out, I don't know (for a start, the guns are said to be powered by heavy-duty batteries - then again, technology will presumably evolve quite a lot in the next few hundred years), but provided you get a projectile up to that speed, there's no way you can stop it again with something you can carry on a spaceship. Nuclear plant buildings are designed to survive aircraft hits using several metre thick walls of concrete, and plating the reactor with that would be completely out of the question. And with that amount of energy poured into a projectile, it would be incredibly wasteful for it to be a simple hole puncher. If it doesn't lose speed traveling through its target, it means it fails to impart much of its kinetic energy onto it. Ideally, you want it to slow all the way down to zero, so the target has to deal with all that kinetic energy. The first impact of the projectile would start a cascade of shrapnel which would also travel at several kilometers per second, taking with it anything in its path and starting new cascades when the shrapnel hits something else. Essentially, a ship hit by a railgun round would turn into a giant shotgun aimed at itself. A hit at that speed would wring the ship inside out. That's why I thought that scene in Persepolis Rising was a bit bull, when...
  11. They are also very fast projectiles. Then again, railguns in The Expanse have always been a little inconsistent, at least in the books. They're not mentioned at all in the first book, then in the next couple of books it's suggested they fire rounds at around five thousand meters per second - which would only make them useful at extremely close ranges, as at a modest 1000 km range it would take more than three minutes for the round to arrive at the place the target used to be. In the later books it's been suggested they fire rounds at "an appreciable fraction of the speed of light", which would make the rounds annihilate pretty much any ship they hit if they had a mininum of splintering capability. Heck, air resistance alone should be enough for them to flash-fry the rooms the rounds passed through, and they'd create pretty nasty shock waves in the process too. But instead, railgun rounds in The Expanse seem designed to pass through the target with as little friction as possible, punching a small, clean hole through the entire ship and exiting on the other side almost without having slowed down at all. It seems like their primary purpose is exactly the type of behaviour you described - going cleanly through walls for narrative suspense. They provide the threat of a "hole puncher" that can make sudden holes appear in the ship, killing anything along the straight line between them, but sparing the guy who just happened to sit in the next chair over. If railguns had provided immediate destruction of the entire ship every time, those "dodged the bullet" moments couldn't happen.
  12. There are very few cases where you want to rendezvous with something and the relative speed difference isn't in the high hundreds of meters per second initially, if not more. You would have to spend a lot of fuel if you want to slow down to the point where inflatable shielding would make any difference on the outcome of the impact anyway, and by then it would be a lot easier to just continue slowing down the final few m/s than to prepare for a low-speed collision. If you're going from a relative speed of 700 m/s to 10 m/s and an impact is impending, you might as well go all the way down to 0 m/s. If you wanted to save propellant you'd have to stop at 200 m/s or something, at which point whatever you're hitting is going fast enough to put a really bad dent in your spacecraft (or itself) regardless of how many balloons you put in the way. And I agree with kerbiloid above, there are stickied threads in this forum for simple questions. No need to create a new one every single day for each new question.
  13. You really like making new threads, don't you?
  14. Ad Astra. Most of it. The movie is pretentious, slow and boring, don't see it. Minor spoilers ahead. An antenna built to search for extraterrestrials(?!?) is built to reach way up into the upper atmosphere. Humanity has bases on both the Moon and Mars, with commercial flights routinely making trips to both. Why bother building such a large antenna on Earth, if that's the case? A tiny little space station near Neptune can apparently send "electromagnetic surges" that wreak havoc on Earth and "threaten the stability of the solar system". Antimatter is involved. How it's obtained, nobody knows. Why the Earth's magnetosphere doesn't redirect it, nobody knows. And apparently a guy on that station has been trying to turn the transmitter off for thirty years without succeeding. The entire center core of a rocket (think a full Saturn V stack with side boosters for getting to LEO) is sent to the Moon. Where a tiny, Orion-style capsule detaches from it and lands. Why bother with the giant translunar stage? Who is the best suited man to guard a VIP on a tour from Earth to Mars? An octogenarian, of course! The best way to travel from one lunar base to another is by Apollo-style lunar rover. Just beware of pirates. The way they are dealt with is hilariously pathetic, a combination of words you don't see often. Lunar gravity is only weak outdoors. If you are indoors, gravity will be exactly like on Earth. Who knew! For some reason, Brad Pitt needs to go to Mars to record a message being broadcast to Neptune. The words "why are we stopping?" are uttered on a flight between the Moon and Mars. Stopping in space, that's a good one. A few minutes later, the audience will also wonder what the hell the reason for that scene was. A research station was in distress. We never find out what happened to the station, but a baboon on board kills the captain of Brad Pitt's ship so that Brad Pitt can be the hero and land it safely when the second-in-command panics over having to do a landing on Mars. Martian gravity isn't weak at all. Too bad Mars is a bit of a hellhole. An anechoic chamber is used to record a message for Dad Pitt. Anechoic apart from the large glass window into an operator's booth, that is. Kinda defeats the purpose of the padded walls in the rest of the room. Said message is sent "by laser" from Mars to Neptune. Everybody is bummed out that they don't get a reply in 30 seconds. Neptune is 2.5 light-hours from Mars even under optimal planetary alignment. The way to hijack a space ship launching from Mars is to climb in via the flame trench (which is filled with water - full of leaves) as it launches. A funny background detail: some numbskull apparently put a high-voltage electrical cabinet in the flame trench too. A zero-G fight scene ensues inside the hijacked space ship. During launch. The three stooges on board mostly manage to kill themselves while Brad Pitt tries to reason with them. The firing of a gun is involved, and a canister full of toxic gas. Flying from Mars to Neptune will always send you past both Jupiter and Saturn. Talk about convenient planetary alignment! At least they skipped Uranus. Locating a space station parked in an orbit of Neptune is easy. Brad Pitt can do it manually, while government search probes have failed repeatedly. Apparently the rings of Neptune are only a couple hundred meters thick! Who knew! You can park your ship above the rings, see a station parked below the rings, and jump between them through the ring itself. It is filled with debris, tennis-ball-sized rocks every half meter in every direction, but that can be easily overcome by holding a metal plate in front of you as a shield while you jump. Won't the impact with the rocks slow you down, or throw you off course? Rather the opposite, in fact, you will hit the station at greater speed than you left your ship! Space stations are equipped with big, spinning radars now. You know, for searching in a flat plane. It is mounted right outside the crew hatch, close to the main hub node of the station. If you cry in zero G, a tear will stream down your face. One guy can maintain a space station for 30 years alone after all his crew mates have been killed. Makes you wonder why they bothered giving it a crew of 27 in the first place... You can surf the shock wave of a nuclear explosion in space, and use it as a method of propulsion to get back to Earth from Neptune. Never mind the hundred-meter thick debris field/Neptune's rings between the explosion and yourself. Bad movie. Bad, bad movie. Not for the science (mind you, Gravity is full of bull too and still great), but for its overly repetitive narration, complete lack of emotion, and slow pace. Don't see it.