Search the Community

Uhh... where did we leave off? Dyson Sphere... system-wide production... extensive use of all immediately available resources... Gotcha. Kay. We're back. Stellar Engine! Left y'all hanging on that. It's a real piece of work, taking the power of a dyson sphere to do the unimaginable: Move the solar system. All the planets, asteroids, and stuff in our system are tidally-locked to our star: "the Sun" (as it is rather uncreatively named). Therefore, by moving the Sun, you can move the entire solar system. How would we do this? Good question. The nitty-gritty engineering bits are all pretty foreign to me (check out Kurzgesagt's video if you're interested), but essentially you just need to make a massive booster using the Dyson Sphere as an engine. You plug it into the sun and fire it up, scooching our solar system along at a few thousand kilometers per hour or something. The main reasons we would want to accomplish such a thing would be to avoid potential interstellar threats, like rogue stars and planets kareening into our solar system and throwing everything around like a furious toddler. Such threats would be apparent to us for thousands of years in advance, giving us plenty of time to move the solar system successfully out of the way. Bear in mind, of course, a rather important thing: the solar system is heavy. While we'd be moving pretty fast compared to your old prius, this would be absolutely nothing on the scale of galaxies. Such movements would still be sufficient over long periods of time, as evidenced by space maneuvers used on smaller scales in real life currently (for example, one of the primary ways we move around satellites is by the use of mirrors. The minute amount of energy light puts into these things are enough to slightly change the movements of the satellites, which over the vast span between planetary bodies is all we really need). Some concerns, addressed: But Faaaadrannnnnn, what happens if Earth swings around to where the engine is shooting its propulsion stuff? Relax. We're not stupid. The engine would be facing downwards in relation to our orbit around the sun. But if it's facing downwards, then wouldn't we push ourselves out of the solar system? First of all, you're really overestimating the overall power of this device, and second of all... no, actually! Our solar system is actually facing closer to perpendicular our galaxy's plane than parallel to it. The exact number is close to 60 degrees, I believe. So the engine would be blasting us more or less along the same plane. Would this even get us anywhere??? No. It would not. Reminder: this is useful for minute changes in our solar system's placement for long-predicted threats. This wouldn't be any useful in a space battle or overall travel. If this sucker's moving at 20 m/s, it would take a million years to move 0.003 light-years. Proxima Centauri, our closest star, is 4.246 light years away. Crunching the numbers shows that it would take such an engine 1.415 billion years in order to get our system over there. And also putting a solar system inside another solar system would be really stupid. So, at the end of the day, while Stellar Engines are cool, they aren't exactly great. We need some real speed if we're going to be traveling from star to star, colonizing distant planets and meeting friendly aliens. Which means now we're getting to the real numbers. Sub-lightspeed This isn't anything new. We go at less than the speed of light all the time! Such is perfectly normal behavior for literally anything that we can consider to be a "thing." The laws of physics dictate that in order to get things moving, you have to impart energy into it. Therefore, in order to make something go fast, you need a lot of energy. Good thing we got a lot of energy, then. Currently, the fastest human-controlled things are little neutrons and such, shooting about through massive particle accelerators to do... things, apparently (depends on how much of a conspiracy theorist you are)--and they go FAST. The numbers say they go at 99.9999991% the speed of light, then collide into each other to create MINI BLACK HOLES (depending, also, on how much of a conspiracy theorist you are). This is proof enough that it is within the boundaries of our current knowledge and technology to achieve such speeds, meaning that it's possible that we could do the same with larger objects. Of course, it's not really that simple. Protons are really small and really light, so accelerating them to lightspeed is kind of a cinch. There was literally a boy scout who made a working one for his Eagle Scout project. When we kick up the mass a bit, though, things get more finnicky. In order to understand this, you have to look at the fundamental laws of physics. The speed of light (or "C", as you might know from the famous equation E=MC^2) denotes the finite and immutable constant of a massless particle. A photon is the single smallest amount of energy you could possibly have: it is, essentially, your perfect "1" for the ultimate calculus of the universe. Therefore, if C is the speed it goes, then C is the fastest anything can go. Ever. Which, of course, is a problem. We can look at energy in another way, though, in its kinetic form: force. F=MA is Force equals Mass times Acceleration. If acceleration is C, then to move anything of literally any mass ever (let's say one kilogram. We'll be using SI units, as C is defined by the meter). Force would equal 1 X C, meaning you would have to have almost three hundred million joules of energy. To move your car at the speed of light, you'd need about 390 billion joules of force. To get your massive party bus going that fast, it comes out to almost 5500000000000 joules. So you can see now just how ludicrous that is. For comparison, the average annual consumption of energy on Earth is... uhh... let's see... 580 million trillion joules... so to get your bus going that fast you'd need about 1/100th of the annual energy consumption... Uh. wait. Hang on. That's global consumption, but by now we've colonized the entire solar system; not to mention the Dyson Sphere. It's ludicrous still, but... Hold up. Are you telling me that this is actually doable??? Alright, it'd take a LOT of energy to get your spaceship going at close to the speed of light--but by this point in time we'll have increased energy production and consumption by several factors. We've nearly tripled energy consumption since the industrial revolution, which was again triple the amount than humanity in late agricultural periods, which was again about triple(ish) the amount used in early agricultural periods. That said, interstellar travel would be to a system-wide species as regular space travel is to us now. It would be incredibly expensive, but still doable. You'd likely have private investors and crazy gazillionaires funding private scientific and exploratory missions into the closest star systems. Such journeys would be decently long, spanning between five and twenty years. It's possible that by now humanity's life expectancy and quality would've drastically increased, so such time spans would be feel shorter comparatively; however, they'd still be incredibly long and arduous missions. Voyagers would have to take large amounts of supplies and perhaps live in more luxurious ships than what average planetgoers would usually use in order to maintain their mental states. The Speed of Light This is a problem. You see, Einstein was at it again with his massive breakthroughs, learning about things like the fundamentals of space and time--y'know. The usual. I imagine he was driving a car when he came up with the idea of General Relativity: the basic philosophy of frames of reference and such. Let's say he was going at 60 mph on the local highway, then passed an older bloke going only 50. To the police officer watching for speeders from the side of the road, they are going 50 and 60 miles per hour, as he watches them pass. His frame of reference has, effectively, a speed of 0. Einstein's car is going at a speed of 60 (gosh, miles; what have I done to myself?). However, he isn't constantly observing the speed of his car, as he is moving with it. Therefore, from Einstein's frame of refence, his speed is 0. That means to him, the old bloke is going at a speed of -10; the officer, -60. To the old bloke, Einstein is going at 10 mph, and the officer -50. And then he crashes into the median because he'd forgotten something his mother had taught him ages ago: don't math and drive. Of course, it's a lot messier in reality. The easy maths work well if you can't observe your own speed, which is a hard thing to do if you're rolling across a bumpy road during rush hour. The numbers would work better if there wasn't any resistance or external things to observe (like the Carmax ads or bridge overhead). If, say, Einstein was in a spaceship going through the cold vacuum of nothing--no friction, no gravity, no nothing--then these numbers work a lot better. Still, the concept remains. Now we get into special relativity, which is a wonderful can of worms that I will gladly open here. Let's say Einstein drags himself out the burning wreckage of what was once his faithful prius and decides to take the trolley home instead. As he arrives at the station, though, it's just pulling out, forcing him to wait for the next one. Annoyed, Einstein watches all the happy passengers rolling out towards their destination through the window. First, he observes Passenger One: a small child bouncing his toy up and down. To the boy, he's dropping the ball one meter down, and then the ball bounces one meter back up. Because he and the ball are moving with the trolley, he only observes two meters of overall movement. However, to Einsten, he also observes the moving trolley. In the time it takes the boy to bounce his ball, the trolley also moves a meter away from its previous position. So while the boy observes a basic up-and-down, Einstein observes an angled down followed by an angled up, creating a sort of triangle. One meter up, one meter down, and one meter across: therefore, Einstein observes three meters of movement. This is what general relatively says. We already went over this. Moving on. Second of all, Einstein observes someone turn on the overhead lights to read the morning paper. However, the light reflects off the floor into the man's eyes, blinding him and making his spill his coffee everywhere. To the man, the light moved one meter down and one meter up (simplified, because I felt like it), meaning it moved two meters at a speed of yes. On Einstein's end, however, he saw it move three meters along with the trolley. Here's where the problem is. For the ball, the maths are simple. Speed is equal to distance over time: the distance was different, the time was the same - therefore, the only difference between the boy's and Einstein's observations was the speed. This makes sense, because the boy wasn't observing the additional motion of the trolley, but Einstein was. S = 2/1 for the boy, and S = 3/1 for Einstein. But light has a constant speed. Always. ALWAYS. We don't actually know why this is, but it is THE RULE. That means that we can't apply the rules of general relativity to the man who used to have a coffee and Einstein. If we did, then S = 2/[fast] for the man, and S = 3/[fast] for Einstein... this would mean a difference in speed, which is totally not okay. Something that we also can't dispute is the distance covered, because the distance isn't a constant or randomly variable in any way. They have to remain at what each of them saw, or the law of general relativity wouldn't hold up, and suddenly traveling by car would get a whole lot weirder. This, of course, leaves us with one thing we're allowed to mess around with: Time. If the distance is x and lightspeed is the constant, then time is the variable. Let's put Einstein back in his brand-new, top-of-the-line Prius Spaceship, then send him for a joyride out into the cold heart of space. As he passes other, inferior spaceshippers along the space highway, he observes them at varying speeds due to the law of general relativity. However, he also observes light from his headlights shooting forwards at their own speed: the speed - you guessed it - of light. The way to conceptualize it is to remind yourself that frames of reference don't need to be human or animal or even alive at all. Literally everything is its own frame of reference: your shoe, your shoebox, the shoe store... even the old shoes left in your closet from years ago! This means that Einsten is in his frame of reference; the space prius is in its frame of reference; and the photons shot out from his headlights are their own frame of reference. What are the implications of this? Well, remember that light has its constant speed of roughly 300 million m/s, and from EVERY frame of reference, it must be going at this speed. That means that for Einstein, who is going at a speed of... let's say 500k m/s (it's a good prius and also in space), he sees the light shoot out from his car towards the rapidly-approaching Space Starbucks at 300m meters in a second. However, for the space highway cop waiting for something to actually happen, he sees the light go at 300m meters in a second... PLUS 500k meters. The difference in apparent spacialities is due to general relativity, as I explained earlier. Remember that Einstein is observing the rest of the universe moving towards and then zipping by him at the speed of his prius due to his frame of reference, while the cop is observing Einstein zip by at the speed of his prius from his own. That means when Einstein sees the light, he's seeing it move at 300m m/s away from him as apparent from his own reference frame of 0; while the cop observes light moving at this speed, but already effectively "pushed" by the prius's speed of 500k m/s. Now there's only one thing left to do: plug in the numbers and see how much time got dilated. speed = distance / time. Distance covered for Einsten going to be 300m, as he observed over the course of one second. The speed of light, of course, is constant, meaning we can plug that in right away. 300m/s = 300m / x. 300m/s (x) = 300m - > x = 300m / 300 m/s. x = 1. Easy. Now for the cop. He saw a distance of 300500000. 300000000 m/s = 300500000m / x. Do all the same stuff as above and you find a brand-new number: 1.006666666...7 So at a speed of 500k m/s, Einstein is experiencing time 1.007 times faster than a person sitting still and doing nothing. Time travel is real, guys. And we're doing it all the time.

Previously on Space Travel: Railguns! Trebuchets! All methods we can use to traverse our local solar system. Things get complicated, though, when we try to look beyond. Halving the time it takes to get somewhere doesn't mean squat when we get to things like light-years. Let's math this problem real quick. The closest start to us is Proxima Centauri (which I knew off the top of my head, btw; FEAR MY POWER). It's just over four light-years away, or 40,208,000,000,000 kilometers from Earth (on average, anyways). That presents a problem that - fortunately - someone already did the maths for. Skyhooks, as projected, would yeet you at approximately 26.7 thousand kilometers per hour into the cold heart of space. Which meaaaaaaaans we could be there in just about... 1501897916.66 hours. Which meaaaaaaaans it'd take roughly... one hundred seventy-one thousand, four hundred forty-nine years. This is, as scientists put it, an issue. Literally nothing of value could be gained from this. Interstellar colonization? No shot. Maybe if we put everyone into cryosleep or some scud like that we could save a tiny fraction of humanity from Earth's last flaming breaths, but... yeah. That won't do for conquering the galaxy. Fortunately, we have other things to look at right now. If humanity is at all interested in colonizing other star systems, then it stands to reason that by now we've already colonized our own. Using up the available energy and resources to us in our system is a massive undertaking, but opens up all sorts of crazy things. Thus, I think it's worth taking a closer look at before we move along in humanity's grand journey. Tier II - Our System Let's take a closer look at all the cool things that us humans could do with our system given enough time and investment. Moon base: We're probably on the moon! Not even probably - almost definitely. It's not a particularly hostile environment, and there are precautionary measures we can take against the radiation and occasional meteor swarms - my favorite being "dig a hole." Most of humanity would probably live underground in massive reformed caverns, capable of creating massive structures with the lighter gravity. Entire ecosystems could be constructed within these habitats... and they'd have to, too. There really isn't any way to terraform the planet, as the gravity's too weak to maintain an atmosphere, and the electromagnetic field's too weak to protect everyone from nasty stuff like radiation. The 'outside' would have to be shielded using [something something t e c h n o l o g y], and it's likely that people would have to get used to keeping space suits handy just in case. On the plus side, though, the moon gives us tons of opportunity for other things. First of all, its lighter gravity means that it's much easier to cast off from. It's tidally locked with the Earth, so it might be worth building a massive elevator on the dark side as a sort of makeshift tether and harness the moon's orbital momentum. However, it's also just as viable to build lots of regular skyhooks around the moon. We could build a bunch of railguns on the surface (which require far less energy), and make the moon a first-stop port to the rest of the solar system. Other stuff the moon has: resources! It's got plenty of metals, which can be used to maintain its own economy as well as being shipped abroad. Solar power could work decently well in smaller scales, but by far the greatest resource the moon has is H-3. The moon could become the first fusion-reactor-powered body in the solar system, and eventually ship out the stuff to other planets as a clean energy source. Mars Colonization: Let me make one thing clear. The reason everyone's talking about building a Mars base is because its close; not because it's viable. It has very little atmosphere (comprised almost entirely of CO2), no global magnetic field, a completely insane weather cycle, and nasty storms of electrically-conducting dust particles that get EVERYWHERE. There's no way to protect against all the space radiation, it's impossible to breath, long exposure to the lower gravity could cause permanent damage, and the literal dirt is toxic. But... it's free real estate. Now, I've never played any of those space terraforming games, so maybe y'all know more about this than I do. Just bear with me here. To first colonize Mars, you'd need to build small, cylindrical structures containing the bare necessities of life. There would be no windows, literally everything would have to be recycled, and the whole thing would be completely covered in dirt to shield the unhappy astronauts from the radiation. Any work that doesn't absolutely require human hands would be done by remotely-controlled drones so as to protect the astronauts from as much exposure as humanly possible. Mars suits would be incredibly bulky, with myriads more protection than required elsewhere. They'd need to undergo a rigorous sterilization process every time an astronaut returned so as to prevent the toxic microfibrous soil from entering the habitat, or potentially never even enter the habitat in the first place (such as by attaching to the outside). Colonizing Mars would be torturous. Fortunately, there are a few things we can do. Mars has plenty of natural resources that we can mine to build things, such as massive containment areas. By far the most viable option would be to construct large reinforced buildings on the surface. Making them airtight would allow us to completely control the conditions within, which means these could be the first viable human habitats for large groups of people. Domes seem decently doable, as they could balance out the pressure most efficiently. However, they'd need to be made with several layers of reinforcement so as to protect the structural integrity of the area. It would probably behoove the engineers to construct several independent airtight chambers within the area itself, so if a breach were to occur, they could protect the vast majority of the dome. Until we can come up with perfect insulation, building underground isn't an option. Any breach could allow the toxicity of the soil to seep into the habitat, which would be... y'know. Bad. There could potentially be emergency bunkers and such built there to evacuate people for short periods of time, but long exposure needs to be avoided at all costs. However, once the planet is colonized, we've really managed to open up the solar system. Its moons are very viable for large-scale skyhooks, and the abundance of natural resources (namely iron) would make it a hub for mining. It might even become a sort of temporary home to big resource mining industries (the habitats would allow you to stay and oversee operations, meaning the planet wouldn't have much or even any regular residency). It would become a industrial and infrastructural hub, and mark our first major step towards colonizing the solar system. ... ... ... ...Venus: Venus is hell. Let me make that ABUNDANTLY clear. VENUS. IS. HELL. The atmosphere is thick. The atmosphere is toxic. It is comprised almost ENTIRELY of carbon dioxide, with an average surface pressure of 1350 psi, or about 91.86 atm. Divers can survive up to 100 atm by not breathing - but, generally speaking, if you're a Venusian colonist, you're going to want to breathe. Not that it matters, of course, because the air here would kill you in instants! Did I mention the fact that it's toxic?? Or that it is literally made of CO2??? There are clouds made of sulfuric acid!!! The CO2 is supercritical!!! The greenhouse gas effect gives the planet an average temperature of 464 degrees Celsius!!! That means liquid lead. That means you won't have time for the supervolcanoes to kill you!!!! Venus is not conducive to colonization. Venus is conducive to death. *Pant* *Pant* ...But I hear you. "Fadran, what if we just terraform it?" Here is a link. It will take you to a Kurzgesagt video. They explain the process. I'm not going to go into it, because - frankly - this article is long enough already. You wanna hear my opinion? My brother just mentioned it, and I wholeheartedly agree. The place burns at gazillions of degrees, spits geothermal forces like a teen's first pimple outbreak, and soaks up sunlight like nothing else. That said, Venus is also the PERFECT thermal battery. We should turn hell into a battery. Mercury: Mining! Don't colonize here. It's either scalding hot or freezing cold, depending on what time it is. No atmosphere. Mining only. No humans allowed. Jupiter: The moons are all perfectly viable. Like, there's tons of them, and they're all pretty cool to boot! I don't have time to go into any of them, but I think they're all decently viable for bases and such akin to the ones on our own moon. Saturn: Prettyyyyyyy!!! Skip. Uranus: Did you know that its magnetic field is tipped away from its axis by 60 degrees? Cool, huh? Moving on... Neptune: We do not need two blue gas giants. Throw some ship names down below so we can finally combine them! Pluto...?: https://xkcd.com/473/ Other Stuff: Asteroids! They're all pretty dang mineral-rich and mineable. Big ones could be viable for early interplanetary resource-gathering. Here's another Kurzgesagt video that goes into that. So is that all? We've harnessed the solar system. And... it didn't really help us at all for interstellar travel. We can build... bigger skyhooks, maybe? There's... nothing left for us to use. Is interstellar travel impossible? The Sun: ... Look forward to part two: Harnessing the power of the sun!