SomeGuy12

[quote name='Stargate525']It's not the storage, it's the read time. As the world gets bigger, the time it takes the game to look up whether it has already generated said chunk increases.[/QUOTE] Minecraft is a hacked together mess put together by a single....extremely wealthy...guy. It's written in both a very slow programming language and the code itself is very slow. Notably, chunk generation is quite slow - just running around the Minecraft world, the whole game hitches and chugs as it slowly creates new chunks. Another issue is the chunks are made inefficiently - bedrock to ground level gets made, stored, and sent over the network connection for each chunk, even though the majority of the time, the player will never dig into a particular chunk and thus never see the blocks underneath the surface layer. (obvious solution is cubic chunks, a solution several clones of Minecraft have used) The Windows 10/tablet version of Minecraft was written in C native code by a team of experienced programmers. If you have tried it, you'll see chunks snap into being basically instantly with no noticeable hitching.

How did you get the bumpmap done right?

[quote name='Findthepin1']So there's this game called EVE Online. It has remarkably asymmetrical spaceships and some of their Earthlike planets are over half the radius of Jupiter. Anyway, the game's universe has over 5000 star systems. They seem realistically enough spread out. I don't understand how they are able to store all that information, for every meter of every planet in 5000 solar systems, plus everything on them and everything in space. It would probably take up tens of terabytes at the very least, or petabytes at the most. Likely, they don't have that kind of capability. What am I missing?[/QUOTE] First of all, the planets don't have 1 meter detail, do they? You cannot get that close to the surface. And second, yeah, you can define a whole planet with 1 meter detail with a handful of random numbers that would fit in this sentence. You generate the actual terrain as needed, or you cache just the portions that players actually have visited. This is how minecraft does it. (notably, the minecraft world does have a practical size limit, but it has to do with the binary size of the numbers used and not the fundamental technique) The real problem with this kind of random generation is that it isn't very interesting. Randomly rolling terrain gets boring to explore after a while, and the ultimate limit is the actual unique resources, such as the textures for the terrain blocks and biomes and such.

[quote name='K^2']There is no fission. The decay is from an excited state to a ground state. The only radiation released is gamma, which is easy to shield from. The only radiation that's really hard to shield is neutron, which isn't released, since you don't change the isotope. And yes, you can control the decay rate. That's the whole point. So lets go over this again. 1) Easy to shield. 2) Releases energy on demand. 3) Long shelf life (~30 years half life). 4) Energy density approximately 10,000 times of chemical fuels. Unfortunately, current costs are closer to million times higher than these of chemical fuels, making it impractical for pretty much any application. But there have been some developments in greatly reducing these. In other words, don't hold your breath just yet, but it's the sort of technology that might be coming in the next few decades.[/QUOTE] As I understand it, gamma is actually really hard to shield against. [URL="https://en.wikipedia.org/wiki/Radiation_protection"]Wiki[/URL], on radiation shielding, says you need 1 centimeter of lead to cut gamma in half. So if the exposure rate off a high end nuclear reaction, enough to roar on engine thrust into orbit, is a lethal dose in 10 seconds 10 meters away, you need to halve it an awful lot of times to get to acceptable dose rates. And you can't fly to orbit if you have to have 30 centimeters of lead all the way around you engine. This is especially bad for flying cars, because there is severe danger if you have containment failure (after the aircraft crashes) and you have to shield from all angles because there are people underneath. (I assume you intend for the flying cars to drop people off on rooftops, etc) Unless you know something about gamma ray shielding I don't, it's one big nope. No way, ever, can humans safely use something like this. Maybe if we were radiation resistant cyborgs with electronic brains that can resist circuitry damage via digital error correction or be replaced when we take radiation damage, but not flesh and blood primates. Frankly, aneutronic fusion sounds more plausible. The primary reaction doesn't produce any gamma rays or neutrons at all (side reactions do), and the fuel is hydrogen + boron or hydrogen + lithium. Nothing exotic. Ironically, flying cars and SSTOs still don't make sense - the fusion reactor, being a big honking pile of superconducting magnets and electric grids and vacuum layers, is too heavy. Power output scales nonlinearly with bigger reactors because your containment systems act on the surface of the fusing plasma, and so larger reactors need proportionally less magnet mass, etc. So you might be able to plausibly make a flying ship that could stay airborne for years on engine thrust, but not a flying car. The engines would be superconducting lift fans, and the fusion reaction would produce electricity by collecting it from the moving charged helium atoms that are the main product. Much easier to get power out than from gamma rays, and the conversion apparatus would be much lighter. Yeah, it might resemble the helicarrier, except it would probably be much more lightly built - thin aluminum and lightweight internal structures, not the thick plates of steel and heavy interior construction a naval vessel uses - and the lift fans would have to be proportionally a lot larger. Also, there would need to be at least 8 or more lift fans - especially if you intend to fly for years, as you need to be able to fly with 1-2 of the fans not running. Still not an SSTO. To do that, you need to beam power from the ground, using lasers or microwaves. Keep the fusion, fission, or just gas turbines on the ground, leaving the spacecraft light.

[quote name='K^2']Quite likely. So we're still going to need to figure out good energy storage if we want to use all that energy for something we're not doing with it now. I still have high hopes for nuclear isomer energy. If someone can figure out a reactor that produces necessary isomers in large quantities without costing too damn much, maybe we can start building flying cars and maybe even electric SSTOs finally.[/QUOTE] How does nuclear isomer energy help with this? A quick perusal of wiki didn't lead to any answers as to whether 1. Can you control the rate of energy release? If it's uncontrolled decay, like RTGs, it doesn't work for flying cars or SSTOs because the reaction can't be stopped (such as when the car lands or the SSTO reaches orbit and needs to reduce heat load) 2. Does it always release gamma rays and neutrons? If yes, then the mass of shielding and the danger makes it unfeasible.

Yeah. I think being stranded in space without power is a lot more dangerous than the radiation. And the problems with neutron shielding between NERVA cores, etc, makes it inconvenient to have much redundancy.

Near the end of Ignition, Clark concludes only one way forward makes sense. You can only get a little more ISP over LOX with exotic chemistry and it is enormously difficult to do, often trading off less fuel consumption of a very cheap fuel for a fuel that is difficult to contain and expensive. Anyways, he describes how you can make a gigawatt nuclear reactor fit in the space the size of a desk. It's relatively straightforward, just a metal assembly made of high temperature alloys and rods containing high purity U-235. Relatively speaking, especially in the 1970s, making something like this was fairly cheap and easy. In space, such a reactor can be used fairly safely, long as you do it after the spacecraft that uses it is in high orbit or above. Nuclear thermal gives you 1000 ISP, which is impossible to do via chemistry, right off the bat, and you can do even better than that with nuclear electric or really exotic nuclear thermal.

Every time you enter a gate, it gains the mass-energy of you. Every time you leave, the leaving gate loses that mass-energy. So in the example you give, the gate you keep entering is growing and the gate you keep leaving is shrinking. The books balance.

Helium is colder than liquid hydrogen, although it has been proposed to use "hydrogen slush" (14 kelvin), which is still warmer than the temperature of liquid helium. I don't see how hydrogen slush can diffuse through metal walls as there is no gas phase. The case of NERVA, you will have hundreds of kilowatts, even megawatts of power available. You can afford to run some very energy hungry cryocoolers that NASA hasn't bothered experimenting with. I don't perceive this to be a problem. (I mean, it's an engineering requirement, but if you have the resources to build an interplanetary NERVA rocket in orbit you can probably pay the people smart and skilled enough to solve it)

What are you talking about? People store hydrogen long term all the time. It's really easy. You just have it in a sealed metal tank. It must be completely sealed, with the valves exiting the tank the kind that don't leak. (I'm not an expert on valve composition, you could just solder the valve itself if you had to) Hydrogen likes to leak but it can't go through a solid metal wall. Then, you mount a cryocooler - NASA has tested some on the ground - on the tank and power it with solar panels, RTGs, or in the case of a NERVA rocket, you have a way to generate power using the same nuclear reactor you can use as an engine. (there are heat exchanger loops that go through the reactor core). The cryocooler recondenses the hydrogen vapor so the pressure inside the tank doesn't rise to the point it explodes. Your monthly losses will be vanishingly close to zero. Why hasn't NASA flown something like this? Actually, they have, how do you think IR telescopes work?

It actually is essentially 100% efficient if you use high energy methods. (I say essentially because 99.9999% pushes the "eventually" off until after the sun burns out so it does not matter if eventually will happen) Only resource on earth that is unrecyclable is helium. You're also totally wrong about "subsurface" resources. Only the thin layer of the Earth's crust is accessible to humans for all practical purposes. So for all practical purposes, we can only access total resources that scale with the surface area of the earth. Since Kerbin has less surface area, that means less total resources - except - you can dig just as deep on Kerbin as you can on earth, because the surface temperature of Kerbin is habitable to Kerbols which appear to be solid, carbon based life forms (you can tell by the greenery on Kerbin). This in turn means the crust on Kerbin must be just as thick as it is on Earth, and on Earth, we rarely actually mine all the way through the crust because it is too much trouble.

A reasonable setup would be similar to the data visualization displays the Carnegie Mellon team won when they won the Darpa challenge...for a rough road, autonomous vehicle, very similar to what you are asking for. I can't find an image handy, but essentially it's just a simple gradient map. One color - we can use white - represents "goodness." It's the combination of a bunch of algorithms working together to guess at how "drivable" the terrain in front of the vehicle is. You see black areas representing "dangerous" terrain" and white areas representing drivable terrain, and the autopilot tries to find a route through the terrain that will stick to areas that are "good enough". The sensor data is combination of lidar and cameras - on the CM vehicle, lidar was only short range, so the vehicle would guess at what terrain features were at a distance, optically. When the vehicle gets close to that same features, it scans it with lidar, and estimates, based on the real world shape of the object, how "drivable" it is. (yes I think this mean the vehicle would be equally afraid of tumbleweeds as boulders because both have a solid lidar return, but only one actually impedes the progress of the vehicle) It stores in memory information about the object it saw, and gradually builds up a database, so as it sees new objects, it learns - in realtime - what they are shaped like and can now recognize them from a great distance. For a futurisitic vehicle you probably could make the lidar a lot brighter and thus boost the scan range. I don't know what you can do to reduce the "tumbleweed" problem - you don't want your autonomous vehicle to be afraid of foil wrappers and plastic bags and cardboard cutouts but I know of no single sensor systems that can recognize all of these things reliably. One more thing - any reasonably competent engineer for a system like this is going to demand overall mapping data. Having your vehicle drive around blind, only able to see what is immediately around it, is a terrible way to make sure you even reach your destination. On a planet with enough atmosphere you'd launch a propeller driven flying drone that would ascend to high altitudes and map enough of the terrain to find a route to the destination, completing the map before you even depart. If there's not enough atmosphere, you'd use a satellite map. So if you had 2 basic autopilot screens, one would be from the perspective of the front of the vehicle, facing towards the direction of travel, and it would show the autopilot's estimation of the safest route to travel between terrain obstacles. The other screen would be from above, and would have a line on it showing the planned route from your present location to the destination, and the remaining distance and ETA.

No. The actual difficulty ordering, from easiest to hardest, is 1. Podiatrist (doctor limited by tradition enforced by law to surgery below the knee) 2. DO (doctor also trained in spinal manipulation, aka ......... Kind of like if Miss Cleo started a school of fortune telling and the schools also offered legitimate training in psychiatry.) 3. MD 4. Dentist 5. Vet Yep, it's harder than anything else to become a vet. And vets make the least of everything on that list, about as much as people with an undergrad degree in a useful field. Vets have trouble finding jobs at all.

Look. I made it personally pretty far. And it's not worth it. Seeing people die is the worst experience you can ever imagine. And the vast majority of serious medical problems you will only have half ass bandaid measures or no real effective treatment at all. It's nothing like on TV. Get a decent job with decent pay and manageable stress, and enjoy the nice things in life.

Well, you could calculate it precisely. Just look at NASA's budget for each year from 1960-1970, using an inflation calculator to correct it to current dollars. (if you were really clever you'd embed the calculator in the webpage your publish your findings on in a way that computes the numbers for whoever reads it) Add those numbers together. Do it again for 1970-1980. If it really is 1/4, that really illustrates how much NASA was cut. I was under the impression that if NASA had the funding, they would have built and launched NERVA rockets capable of reasonably efficiently putting a large spacecraft on the Mars interplanetary burn. There would have needed to be a crew of dozens of astronauts and partial closed cycle life support. Maybe a few would die from radiation poisoning eventually. It could have been done.

422 billion? Is that from 1960-1970, with 110 being from 1970-1980? Is that in today's dollars or the currency at the time?

He probably doesn't have the pre-requisites, either. If he started in the United States, say, with a bachlors degree and an average GPA, he'd have to first spend about 2-4 years taking classes full time and taking and retaking the MCATs just to get his numbers high enough to even be considered for med school. (with no guarantee of success, either - all the schools might just reject him every time, it's a dice roll) Then he'd have to spend 4 years in med school. Then an average of 4 years in residency. 3+4+4 = 11 years. He'd be 40 when he finishes. If he already has a degree and a job that pays decent money, he'll never catch up financially. He'll be treated shabbily for a decade. It's not impossible, just not worth it. I wish I could be a rock star, but I can't.

It's just how it happened to have worked out. The "total of 6 years" is how initial medical training should have worked in the United States, just like the metric system, but it doesn't and there's too many entrenched institutions who have no plans to change and too much power to be made to. There are 6 years MD programs in the U.S., they are just very rare. (I'm talking about 2 years of undergraduate basic science, 2 years of med school science, 2 years of clinicals). In both Poland and the USA, there's some post medical school training for doctors to actually learn on the job what they are doing in a specialized area. In both countries, graduates are considered "doctors", however, in the USA, interns and residents get treated very shabbily and they are not called "doctor" by other physicians even though they do hold the degree of MD.

These just push the problem out. How did those universes get created.

Sure. Encapsulate math as series of functions. Write papers using html or a more complex method, and embed the math as a series of nested functions. Never reuse symbols - use complete words. Never bother with showing algabraic simplification, just encode a command to an automated algebraic simplification tool, the source of which is embedded as well. Oh, and don't perform integration if the answer is not universally applicable in your field. If we did all this, it would cut by a factor 10 the amount of education needed to read and use and manipulate math, and it would expose a lot of poorly encoded functions accepted by mainstream science (like the fluid dynamics laws which have discontinuities in them), and it would let people who have studied a different field of math actually be able to transition to another field without another 5 years of education.

Depends on the game, the physics model, and so on. Are you talking about in a realistic simulation style game or in real life? Because if you're talking about a game, you ultimately need a single piece of information : whether a given piece of terrain (you can divide it into 2d squares) has too much steepness/large elevation changes for the drive system of the vehicle in question to traverse it. You subdivide the 2d squares into squares that are about 1/4 to 1/16 the total "footprint" of your vehicle. Your drive system for the autopilot either : 1. Proceeds directly in the direction of the waypoint until it encounters a set of squares the vehicle cannot traverse 2. Uses A* to compute a path to the destination from start to finish and follows that path #2 is better for AI controlled vehicles, I think, because I find it immersion breaking to have AI controlled vehicles in a game get "stuck". I think it is a superior solution to have the AI controlled vehicles never even move if there's no valid path to their target than have them 'running against a wall" fruitlessly trying to get there. #1, you could do limited A*. You have a certain "bubble" around the vehicle covered by sensors. Once you encounter non traversable terrain, you try to find a path to the far edge of the bubble in the direction of your desired waypoint. If no path exists (say the rover encounters a mountain range blocking the way, the autopilot shuts down the vehicle and sounds an alarm)

I'm addressing K^2's assertion that there's no "time outside the universe". In fact there could be time outside the universe, if universe 2 spawned our universe, universe 1, at a particular time. And so on. Many many theories could involve it. His north pole analogy is meaningless. He names a theory that doesn't involve said time outside the universe, but has zero measurable evidence to back it up - thus it's just masturbation by mathematicians. It's so stupendously complex, and uses so many esoteric symbols that read as line noise to most people, that the tiny number of people who understand it are the only priests who can say anything about it. Just recently I was able to break down a similar mess of ........ math into simple rules, and get a motor drive working, and I've concluded that a lot of the math in my field is flak thrown up by marginally productive PhDs to protect their job. There are multiple ways to represent anything, and complex math is one of the least efficient and most timewasting methods. I mean, greek symbols that get reused in every paper and mean different things...

Now that's just politics. Relying on engines that have to be imported from a semi-hostile foreign country for crucial "national security" satellite launches is a bad idea. But if ULA has the rights to produce an indefinite number of the engines in the USA, and actually started manufacturing them, I don't see what the problem is.

Relativity != differential geometry. You can have one without the other. And I'm not saying the math isn't valid, I'm saying there's no empirical proof that this is how the universe really works (and therefore the non observed conclusions are correct, as in, things we can't measure that differential geometry predicts are true) It's like string theory. Vibrating strings use very simple equations and there's a way to build a whole theory of everything based on ever more esoteric math. Inconveniently, the "strings", if they are even real, are too small to ever detect with any experiment anyone has ever proposed, and it's very likely they are not even real. (the reason it's vanishingly unlikely the strings are real entities is because there's a near infinite number of ways to build up a hypothesis from whatever math you have on hand to describe your observations. since we have no actual empirical detection of strings they probably don't actually exist) This differential geometry stuff is just one possible explanation for time that is not necessarily in any way correct.

What experimental evidence indicates that differential geometry is anything more than a hypothesis? I have read about precisely none, and in terms of factual validity, these theories are only slightly better than turtles all the way down.And even if you have a theory that time is a property that is related to the geometry of the universe, what about causality...