What does it mean when a game is made with a certain engine? What do “engines” do?

  1. They do all the hard work that underlies every game but gets repeated for every game. Basically set up the 3D or 2D world. For example Unity or the Unreal engine are (mostly) 3D engines that will handle all the low-level setting up of the 3D world, so all the developer has to do is throw in the models, the animations, the sound files etc; (the assets), design the GUI, specify the lighting and any special effects required like shaders, and then write scripts to show how everything should interact. The low-level stuff the engine would take care of are things like the fast rendering (drawing) of the polygons (shapes) that make up the meshes (models), collision detection, physics if you want it and so on. All the grunt work.

    Little Big Planet is pretty much a 2D engine for making platform games. Gary’s Mod is pretty much how you would use a 3D engine to make a 3D game (without scripting.)

  2. You probably know what Photoshop is

    Imagine if you had to program Photoshop from scratch every time you wanted to edit a picture or do a painting.

    In this case Photoshop is the game engine, the picture is the game. You use photoshop as a tool to create the picture.

    This is very figuratively speaking.

  3. ELI5: An engine is like a coloring book. Someone takes the time to draw the lines so all you have to do is fill them in. You might use different colors than another kid in your class, but you’re all using the same drawing.

  4. Games are composed of many parts: audio, graphics (visuals), input (controllers/keyboards), and game rules. A game engine is a program, just like a web browser or a calculator, that does everything involved in letting the people making the game put the game together.

    Basically, a game engine is a program that runs games.

    To explain a bit about game development in general, the usual process goes something like this.

    • Someone has an idea for a game they feel is worth investing lots of time and possibly money in.

    • That person designs the game (or pays people to design the game). They write out things like the story, rules, and things the game will need to be made. Often times the game is redesigned during development or the design is not finished before development starts.

    • The person gets to work or hires people to get to work on things like art (3-D models, 2-D sprites, concept art, special effects), sound (music, sound effects), design (layouts for levels, balancing numbers, writing dialogue), production (making time sheets, assigning tasks, figuring out how much time everything should take), marketing (releasing trailers, talking to the press, getting the game noticed), business (finds the money needed to make the game), and programming (writing a game engine or modifying an existing one, creating the game rules, making software tools to make content).

    • The first step of making a game is called prototyping. You make a very, very basic version of the game that is likely to be thrown away entirely. It is used to make sure the idea is, indeed, a good idea.

    • After making a prototype (or in rare cases after designing the game), the person or team decides how they’re going to support themselves as they make the game. Often, this means finding a publisher who will pay them to make the game. Sometimes they will find investors who will give them money to see the game completed and expect a return on investment. And sometimes, it simply means supporting yourself and not getting paid (indie development).

    • Once everyone has decided the game is going to be made and things are in order to get it made, the person or team gets to making what’s called the Alpha build. In this stage of the game, it is not yet complete in many ways. There’s often no sound, stand-in graphics, whole rules systems are not in effect yet, and the game’s design evolves and changes.

    • After the game has most of its features done (its game rules are defined and playable in game), a substantial amount of art and design is completed, and the game is primarily what it’s going to be like when the players get a hold of it, they say the game is in its Beta stage. Typically there’s two parts to Betas, the closed Beta and the open Beta.

    • Once Beta starts, almost no new features or rules are added and the focus is primarily on refinement. Usually this refinement is done through art and sound or by fixing bugs. Quality Assurance (QA), or play testing, becomes a big focus in an effort to make sure there’s no bugs and the game is fun.

    • After the people making the game feel the game is ready, or when they are required to release the game (say a publisher says they must have it out by this date), the game releases and it is called “going Gold.” Gold is a released game, even if it is not done in the eyes of the people who made it, it is done according to players.

    • Once the game is officially released, typically most games go into Post Release, a stage where they fix bugs that were unknown while making the game or adding new features. This also includes things like making and releasing DLCs, maintaining game servers, and running customer support.

    EDIT: Formatting.

  5. MS-word is engine for text editing. Without it you would have to create your own text editor first.

  6. Another way to put it is abstraction. The whole way our computers work are based on abstraction layers above abstraction layers. What this means is that each layer encapsulates the one underneath it so if you work above it you don’t care what’s underneath.

    The processor in your PC has transistors. Those transistors are arranged in logic gates so you don’t have to take care of each individual transistor but just functional units.

    At some point you reach the operating system which you, as an user, can use.

    If you’re writing code you have languages such as Java or C# which transform the easy to write code you write into the assembly programming language for example, which the processor understands. Again, this is to make life easier.

    It’s the same with engines. A person spent time and effort to make an abstraction layer that helps you with doing something. Now you don’t have to take care of how each pixel is rendered on the screen or collision detection or gravity etc, you can just add parameters to objects created in the engine which does the rest for you. You can also imagine it like how at first animations were made by hand but now you can do them on a computer much easier. Yes, you do draw it once, but the computer can take care of the rest.

    That’s why people talk about engines being badly optimized etc. The engine does most of the work. It doesn’t matter what you do as long as the engine is inefficient.

    Sometimes the engine has limitations. See DayZ. The guy who made the mod (for the Arma 2 game) decided to make a standalone so he can fiddle around with the engine, which he couldn’t do before. The engine of Arma 2 wasn’t made for what they wanted. So it needed changing, or zombies would always jump around and glitch horribly.

  7. Car analogy time.

    A game engine is a lot like an automotive platform in that it provides the main working components that make the game function.

    So, where an automotive platform might encompass motor and transmission options, frame, chassis, suspension, steering mechanisms, brakes and ECU, a game engine will have libraries for 2D/3D graphics, sound, physics, collisions, networking, input and scripting. What’s left in both after platform/engine development is to design and bolt on the components that the end user will see and interact with; in the case of the automotive platform it would be things like distinctive headlights and grille, fenders, dashboard with instruments and electronics, seats, door panels, etc. whereas with a game engine you would add models and artwork, recorded sounds and music, rules for game mechanics, scripts for game elements and levels, etc.

    Two cars made on the same platform will show similarities to each other in much the same way that two games made with the same engine will. For example, with the above linked GMT platform you’re basically going to get a large SUV such as a Chevy Suburban or a Cadillac Escalade whereas with the above linked Unreal engine you have games like Batman: Arkum Asylum, Tom Clancy’s Rainbow Six: Vegas or Tony Hawk’s Pro Skater HD which all are 3D first/third person with a directly controlled single player character (per player) and player perspective (camera) close to the characters and action.

    The nature of software, though, does make it possible to have a game engine able to function over a wide range of end products. Unity can go from 2D pixel art puzzle games to 3D first person games on the same engine whereas an automotive platform able to go from SMART car micro compact to full size SUV is unlikely to say the least.

  8. An engine is like a film set/lot. You quickly realize what you can do with the provided location, light, size and rules for filming (where cameras can be, how many angles you can shoot, angle, etc.) – You get to choose the cast, story, genre, etc., but your set has limitations. It’s also why you wouldn’t use a set with exploding cars for your who dunnit puzzler show.

  9. Made an account for this. Imagine you and some friends want to go make a foursqaure in your driveway to play in. You’re all really excited and rush out to make it, and then realize you have no chalk. So you all put your heads together and try to figure out how you’re going to get chalk. One friend says that you should should head to the mountains and find some chalk to draw with. Another friend says you should head to the ocean and find some chalk, and still another says we should just buy it at the store.

    Nobody can agree on anything so you all decide that you’re going to do everything and decide which is best. Your friend that found the chalk in the mountain comes back with a grey chalk that is really dusty. Your friend from the ocean comes back with pure white chalk that doesn’t turn to dust so easily. You come back with chalk from the store in different colors that is right in between the two.

    You all head to the driveway to make the foursquare but realize that to find out which chalk was the best, it would be best to make three foursquares. The grey chalk makes big bold lines, the white makes thin lines, and you store bought chalk makes lines just in between.

    In this analogy, the chalk is the engine, the foursquare is the game and you are the designer. Your friends all went out and made their own engine(got their own chalk) while you bought a license for an engine(bought your chalk). The different kinds of chalk make different foursquares, and while they looks and behave different, they’re all still foursquares.

    It’s important to remember that the chalk was just a tool to make the foursquare. You and the foursquare existed without the chalk, the chalk just made it easier to make your foursqaure. You(designer) used the chalk(engine) to bring forth your foursquare(game).
    The foursquare was much easier to make with your store bought chalk, but you lose some control over what the foursquare looks like. Your friends who went out and found chalk(designed their own engine) have more control, but much greater effort is required.

  10. TL;DR – It’s an empty video game.

    An “engine” itself is the technology behind the game; all of the fundamental stuff which takes months and often years to get working right. After the engine is complete (or often times, when the engine is usable enough to start some work) the developer will began work on the game.

    The developer will do additional programming (known as scripting) to create what is known as “game logic.” Think of this as the rulebook a game will follow. This kind of programming is basic stuff. For example, if a player clicks the left mouse button, fire a gun. This kind of programming is generally quick. In fact, the bulk of development time on a lot of games is building the engine.

    With every game engine, there is what is known as a software development kit (SDK). The SDK refers to a group (a) program(s) used to design the game without having to do it all through code. It’s essentially a computerized set of building blocks. You have basic shapes like cubes, cylinders, lights, etc that you can place throughout your level, as well as tons of other features that would be too complicated to go into right now.

    The reason there are so few game engines is because they take so much time and money to develop. It’s much simpler for a company to pay someone like Epic Games a license to use their engine. So they pay the money, Epic gives them the engine, and the studio can start work from their “empty game” right away. Someone used the analogy of opening a picture in Photoshop versus programming Photoshop from scratch each time, which is spot on.

  11. A game can from development perspective be divided in two segments: assets and code.

    Assets are textures, music, videos etc, 3D models and animations, scripts and such.

    Code makes it all work – calculates positions of objects, game mechanics (often enhanced by already mentioned scripts), takes care of correct rendering, deals with networking..

    If the game code is structured “correctly”, it has the ability to be easilly used with other assets, and to be easily extended/modified in some parts. That code is a game engine – although all games technically have an engine, usually it is only referred to as an engine if it is so structured and used in multiple games.

    An engine usually has distinct “subengines” – for graphics, physics, AI, networking..

    Real ELI5:
    An electric car has an engine which makes it go, and nice plastic parts. You may change the nice plastic parts (and even wheels), but the engine is the same, and it still makes it go.

    If you change the pictures in a game, you get a new game, but the strange words daddy writes on the computer make the game go.

  12. Think of it like making a movie.

    You don’t invent a new type of camera, lights, microphone, set, harness (for flying sequences), green screen etc. You use what has been proven to work.

    You do have a new script, costumes, make-up, special effects however.

    In this analogy the camera and lights would be the rendering engine which draws everything to screen, the harness would be the physics engine (which determines how far and fast a car flies when you hit it with an RPG).

    The stuff you redo like the makeup and costumes are the textures and models.

  13. You know, how when you walk, you don’t think in terms of “Oh, now I have to lift my right knee up by flexing my thigh muscle and then putting forth my right foot” and so on, but you just think, “hey, I wanna go over there”. An engine is the parts in your brain that makes you walk without thinking how to.

    In computer programming, when I want my bot to run around searching for people to shoot, I simply tell the bot “run around here and over there”. The engine handles the rest.

  14. Think about Microsoft’s Power Point program, for a second. Whenever you view a powerpoint presentation, you need to things: the power point “presentation” file, and the Power Point “engine” program. The “presentation” file contains information about what text/pictures are on what slide, when sounds should play, which transition to use and when, etc. The Power Point “engine” program is responsible for interpreting the contents of the “presentation” file and displaying them on screen. You don’t need any programming knowledge to make a power point presentation, but a great deal of programming was required to make the “engine” that plays the presentation.

    Games are the same way. Take for example, the Unity 3D engine. A Unity “project file” contains information such as level data, sound data, textures, 3D models, and a tiny bit of code to tell the engine what to do with it all. The engine, therefore, is the mass of code that is supposed to take the information in the “project file” make sense of it, turning it into something that resembles a game.

    A simpler way to look at it: every game has a “level editor”, which creates a “level file”. The game engine can be thought of as a level “player”, in that regard.

  15. As others in this thread have already pointed out, a game engine is simply a lot of code that doesn’t need to be changed much, if at all, from game to game.

    An example of this, from my experience, is when I created the game-loop (a loop that continuously updates the logic of the game and then displays things on the screen.). It took a while to create the first time, but now, whenever I start a new project, I just copy-paste the game-loop over to the next project and it works right away.

    A game engine is a HUGE collection of things such as physics, particle, shader, keyboard/mouse control, etc… systems which don’t need to be changed very much if at all between games. You just grab what you’ve made before and get to work without spending hours rewriting the same thing over and over.


    Programmers don’t like to rewrite code, so we write it in a way that allows us to reuse the same piece of code over and over with little to no changes.

    When a game is made with an “engine” it is just reusing code that was written before to speed up the development process of the game.

How do fish food companies make any money when one little container lasts so long?

  1. Partially, because there are people like me who keep large fish that chow down on that stuff like there is no tomorrow. A $10 block of gel food? That’s like a week, max, for my oscar once she is full grown. A $20-35 (depending on brand- I have a few I like and alternate) thing of semi decent quality pellets (Ie, not all filler and crap but actually half decent) is probably a months worth. Now imagine having a tank of them, or other large fish. It adds up fast.

    (When keeping large fish I tend to make my own gel and supplement with pellets and other good stuff so the food tab stays reasonable and so the nutrition is the best possible, as relying on pellets and dry food alone is not good IMHO. By the time I had a few tanks and ponds going, it was buy your dry food in bulk and/or make your own, or ship out, because I started this hobby in school and had a LOT of fishy mouths to feed on a student’s income. As a result I did a lot of research into fish nutrition, where I could cut corners, where I could not, what was the best nutrition, etc. But, there are a lot of serious keepers out there who spend a lot of money on getting the optimal nutrition to their fish and who do not make their own food, as well as aquaculture farms.)

    Most of these companies that make cheap fish food also sell aquariums, filters, etc, and that’s where the bulk of the money is. Good fish food companies who create good, solid diets in their product sell for more and there are many specialist fish food companies, or brands that offer much better premium foods.

    Now, I’m going to get sidetracked a little and onto fish nutrition. The cheapy 5 buck flakes or pellets are generally not optimal- They contain a LOT of filler material with little nutritional value. Some are ok (wardleys goldfish flakes for example, while cheap, are decently nutritious for that species for that price range, though with fancy goldfish you really should be feeding a sinking pellet though) but most are full of wheat, corn and other things our fish do not encounter in the wild, or digest very well. For example, a carnivorous fish probably should not be on a cheap pellet that is 50% grain filler. This is not providing an optimal diet to them at all. As some diseases are linked to inadequate diet, for example HITH in oscars seems to have links to bad diet, every fish keeper should be trying to provide optimal nutrition to their fish. Plus, in the event they do contract something, healthy, well fed fish bounce back and have better survival rates then those not fed as well.

    These cheap pellets, because they are full of filler, are cheap to produce. So even being sold at what seems to be a low cost, there is often a decent enough profit (percentage wise) on them for the makers, and the stores, to keep producing them. Plus, most people need prepared dry food (flakes, pellets, sticks) to be able to buy fish, which in turns creates sales of aquarium and products, which in turn drives up profit by enabling the sale of other non food products. As most stores that do the brand thing only stock a few brands, by having their food available they encourage purchase of their other products.

    Therefore, keep in mind that you should research dry food brands (dry food being flakes, pellets, sticks, etc, that stuff) and find the best you can. Keep in mind different species have different needs, and to get foods formulated for your species. For example, cichlids should be fed a cichlid or similar feed (for example, my oscar is currently on a flowerhorn feed for the increased protein because she is still growing, but they are both fish with similar dietary needs and both cichlids, so this is no biggie) which is high in protein and what they need, while goldfish and koi should be fed a carp feed (and if you are wintering these fish outside and seriously keeping and breeding them you get further into different nutrition for different times of the year etc) with is formulated to their needs and so on.

    Dry food is not the be all and end all of feeds either- That would be like feeding a dog or cat cheap nasty kibble its entire life. It’s a staple, sure, but a GOOD diet is supplemented with other foods (But please don’t be a dick and feed live fish to other fish unless necessary- Large predatory fish generally will eat FINE without this cruelty and you’re only doing it for your amusement. I’m talking about things like bloodworms, blackworms, earthworms, waxworms, or gel foods containing meat and vege etc here, not live fish or mice or any of that BS. Live fish can also vector disease and feeder fish and pinky mice are not overly nutritional at all to most fish. Much better to stick a cube of gel food in there instead. More humane, and more nutritional for your fish, and much more fun to watch them stalk, grab, and chow down on then a suffering goldfish or other. Seriously.) which can be bought frozen or freeze dried. If you have fish who need a high vege content (like plecos) you can supplement them with tidbits of cucumber and similar from the kitchen. Goldfish will eat from a vege clip too once they figure out it is food (though it can take them time to realise if they have been on prepared dry food their whole lives) which is a nice way to spice up their diet without making it too protein heavy (though they also enjoy, and should be fed, bloodworms and such- Balance is key though. They also need a fair share of vegetable matter for optimal health). Fighting fish go crazy for bloodworms and other things too, and along with a quality pellet this can make a good (and cheap- a frozen block of bloodworms is like 4 bucks and in theory will last years for one fighter- Though you probably should turf and replace them occasionally anyway the same you would for meat products, being insects and all. I’ve never had mine last long enough to tell you when to do that, sorry!) diet for the home hobbyist with only one or a few fish to feed (where going to the trouble of making your own gel and dry foods is not worth it)

    Also remember to REPLACE your dry foods regularly- That one tub of food you have had for 12 months is likely stale and has lost a lot of its nutrition, and this is double bad if you’re only feeding that food, because assuming it was originally close enough to meeting the fish’s diary needs that it was ok (if not fantastic), there is no way it is now. If dry feeds are not use within 3-6 months of opening they generally should be disposed of and replaced. You wouldn’t eat year old chips, so don’t feed similarly stale junk to your pets. Similarly, a nice analogy is that while bread is good for you, that cheap shitty loaf of white bread is not (cheap feeds with too much filler), and even if you buy the best quality bread it’s still probably not healthy to live on that alone, even if it is formulated somehow to be as close to your dietary needs as possible (vitamins and minerals and protein added, etc), especially once it has gone stale. Variety and a varied diet geared to replicating your fish’s natural diet is key.

  2. They probably make most of their money through bulk sales of their products to fish farms; the pet-sized brand label is a side business.

  3. A lot of people own fish. So someone is always running out.

  4. Companies like that usually have many different sorts of products.

  5. Probably because there are always ‘new’ people to sell it to. Almost every kid has a phase where they want to own a fish.

  6. I’d guess it’s from when your dog or cat or kid knocks it over and you have to get more. Happened to my family a lot

  7. Slightly off topic, but I am amazed by how many people are claiming how long they have been using the same food! After a while the food begins to loose its nutritional value, one of the first to go is vitamin C. This alone can cause loss of color, all the way up to crooked spines and death. After a year, you might as well feed them cardboard. Would you feed your, dog, cat, self, food that had been siting around in an unsealed container for years? Just because it is a fish doesn’t mean you shouldn’t give it some quality of life. Damn thing is probably in a little glass bowl as well…..

  8. Tiger Oscar owner here. They don’t need to make money on Betta food when we’re trying to keep our big ugly poop machines fed.

  9. Its cheap to make, and other people use it up quicker than you do.

  10. They sold you .02 cents worth of product 5-20 bucks that is how. Lol

  11. I haven’t needed to buy fish food in nearly 4 years. If you look at the the “low end” brands (not Hikari) I’ve noticed many of the packages say “Feed 3 times a day. Enough for your fish to eat in 5 minutes.” This just blew me away. When I worked at Petsmart and Petco I always had customers who followed this rule, were in every week for more food, and always wondered why they could NEVER get their ammonia/nitrite levels down. When I told them to reduce feedings to once a day and the amount they will eat in 20-25 seconds they treated me like some horrid person wanting to starve their fish….

  12. I figure that with 7 billion + people on this planet, there is always going to be a demand for almost anything out there.

  13. The fish foods directions recommend you feed a lot more pellets or flake than is suitable for a small fish. Companies tell you to feed more than is recommended hoping you run out faster and buy more.

  14. Maybe those fish would have survived if you had fed them more

  15. R u feeding your fish enough? They could be starving!

Why do chips get chewey when go stale?

  1. Frak is actually kinda right. In chips they absorb moisture and get soft (edit: well, this occurs in chips too). However, the reason baked goods go stale is because the sugars are polymerizing into longer chains, hardening the baked ~~h~~goods. That’s why you can revitalize bread by toasting it, you break the long chains with heat.

  2. This is the most important question ever made

  3. True Fact; that is actually the only defining difference between a Cake and a Biscuit. The Cake when stale hardens, while the biscuit softens.


    I am food science undergrad, so I could be wrong. But I am following my textbook!

    To make this as simple as possible. Food has different WATER ACTIVITY. Not moisture but WATER ACTIVITY. To simply put, water activity is the amount of water in between molecules available to nature. The lower the water activity, the harder for the food to spoil as it water gets hard for germs or fungi to access it. This is why bread spoils so much faster than crisps as bread is freakin high

    Why bread goes stale? Bread’s water activity is pretty high. The maximum limit for water activity is 1. Bread is 0.95 and crisps is probably 0.3.

    Water is trying to attain equilibrium, hence water leaves bread to the atmosphere while water enters crisps to make it soggy. This is why the modified air in your crisps has to be delicately be in balance.

    Does this answer your question? Feel free to correct me if I am wrong!

  5. As an aside, there was a British court ruling on Jaffa Cakes. The court decided a biscuit was baked hard and would soften with time, and a cake was baked soft but would harden with time.

  6. There is a certain amount of moisture in the air of our homes/places where we keep our foodstuffs. Crunchy foods have less moisture and thus will absorb some from the air. Softer food will harden from the outside in as water vapors act as a catalyst, causing starches to crystalize.

  7. ~~It’s all about how dry/moist the food is relative to the moisture level of the surrounding air. The food will soak up water or evaporate its water content in order to reach an equilibrium with its surrounding atmosphere.~~

    Edit: Sorry folks, jumped the gun on this one. Sagan4life and xenoguy1313 have the correct explanation right here, which was posted several months ago in /r/AskScienceDiscussion.

  8. Chewy is a fun word to say.

  9. Bread goes stale and yet fucking croutons go soft, what’s with that?

  10. This post belongs somewhere on r/trees.

  11. Lots of people are explaining why individual food gets crunchy or soft when it goes stale, which I don’t think addresses the heart of the question. The question is, why does “staleness” consist of two opposing things?

    The answer is that “staleness” is not a single process. When different foods go stale, it’s not the same thing happening every time. Lots of food changes over time, but “stale” implies that it has become unappetizing without becoming inedible.

    So if you made a crunchy chip that became inedible, we would say that it “went bad”. If you made a chip that remained crunchy or became crunchier, we would say that the chip “does not go stale”. We define chewy chips as “stale” because they are supposed to be crunchy, and they’re no longer crunchy. Bread, on the other hand, is supposed to be chewy, so we define staleness as when it becomes hard.

    In other words, the idea of “stale” is inconsistent because it’s not an actual scientific process, but rather about human interpretation. It’s a little like asking, “Why is it that when it’s hot, ‘having the temperature become comfortable’ means that it gets colder, but when it’s cold, ‘having the temperature become comfortable’ means that it gets hotter?” The answer is that you’re dealing with human assessment against a desired state, and not an absolute process.

  12. So many wrong answers here. Bread doesn’t get crusty because it’s losing moisture. It’s gaining moisture and crystallizing.

  13. The same way hot chocolate gets cold and soda gets warm.

  14. This is why Jaffa cakes are Jaffa cakes and not Jaffa biscuits…

  15. I usually eat the entire bag of chips after I open them. Never stale.

How are engineers able to build subway tunnels under already built infrastructure?

  1. There are multiple ways that they can do it. Here in Boston where I live they finished the Big Dig a few years ago. Over the course of roughly ten years they consolidated all the utilities through a corridor of the city and then sank an entire elevated highway underground. It had to go above and below various obstacles like a subway tunnel, a waterway, and Boston Harbor itself.

    The main corridor of the sunken highway, I-93, was built in multiple sections. In parts of it they simply closed down the ground-level street for a few months, dug a 100 foot deep pit, built the tunnel, then filled the hole back in.

    In another part where they had to dig directly under the existing elevated highway they first sunk steel girders 100 feet down to the bedrock, filled the area around them with concrete, then supported the existing highway on top of that while digging out the dirt and building the tunnel underneath.

    At one spot they had to build the tunnel underneath an existing subway station that was itself underneath a very busy surface road in the middle of downtown Boston. To do this they first dug two vertical shafts to below the level of the subway station. They then dug horizontal tunnels underneath the station, supporting them with concrete. From those tunnels they dug hundreds of tiny shafts and filled them up with concrete. Eventually they formed it all into a complete set of concrete walls that formed the new tunnel. If you scroll close to the bottom of this page you can see a series of graphics that show how it was done.

    Another section of tunnel had to be built under multiple train tracks just outside one of Boston’s main train stations where thousands of commuters pass every day. The soil under the train tracks was pretty soft so they had to figure out a way of building this tunnel without making the tracks sink into a sinkhole or anything like that. What they did in this case was to sink hundreds of pipes into the ground and then injected freezing water into them in order to freeze the ground solid. They then dug a pit on one side of the tracks and built an entire tunnel section there. They then used giant hydraulic jacks to pull the tunnel section underneath the tracks as they slowly dug out the frozen dirt underneath them. Here’s a page that describes that process.

    Although not used in Boston, another typical way of building tunnels is by using a tunnel boring machine (TBM). A TBM is basically a crawling machine that can dig out dirt or rock in front of it and then immediately seal the circular hole it creates with reinforced concrete.

  2. Very, very carefully. They’d normally avoid it, and subway tunnels go under roads: but if they dig deep enough to avoid weakening the foundations of a building, it can be done, assuming the local geology will allow. Sometimes buildings may be built with the expectation that a subway tunnel will be built under it in the near future, and the foundations designed accordingly.

    It doesn’t always go well, though. In 2009, construction of a subway line near the Historcal Archive of the City of Cologne, Germany, caused the ancient building and two other buildings to collapse, mercifully causing only two deaths. However, 90% of the archive, including documents going back to the year 922, was buried. About 85% of them have been recovered, but some of them badly damaged. A new building is due for completion in 2017, but restoring the documents is likely to take another 30 years.

    The tunnel wasn’t even under the building, but next to it, and being built using the traditional “cut and cover” method. But water seeped out of the tunnel and into the buildings’ foundations; workers were able to raise the alarm in time, hence the very few casualties, but only just.

  3. Using this big worm drill. http://4.bp.blogspot.com/-LfS9ojQ1CAQ/UTm0oThdLBI/AAAAAAAAAl0/RAORkZPeBEM/s1600/59087367boringmachine976.jpg

  4. With London if I remember correctly there hadn’t been good documentation of buildings to account for depth of all that the tube would pass under. Some lines like the Piccadilly line and Northern line are incredible deep to account for this. Others building surveryors were called in to assess already built buildings to judge whether they could withstand a tube line being built and at what depth.

  5. It’s not always foolproof. In chicago, old mail delivery tunnels were breached when bridge pilings went thru them. Flooded the basement of every building downtown.


  6. Because we’re bosses, that’s why.

    Actually it’s hours and hours of trial an error and looking at existing plans for the already in place infrastructure 1000’s of times making sure you don’t miss anything.

    Source: Structural Engineer.

    Edit: Also, and I can’t state this enough, an immense amount of communication between different types of (usually) specialized Civil Engineers. Civil Engineering is broad (Usually broken up into Structural, Geotechnical, Transportation/Roadway and Environmental as the basic broad sub-categories) and it takes several specialized Civil Engineers working together to get things like this done.

  7. I see digging experts here, so I have a related question. There’s a subway construction in Berlin and during my last visit I saw strange pipes over streets, like these: http://www.worldmeetsgirl.com/wp-content/uploads/2013/10/berlin-3-things-2.jpg. They are very long and twist over quite a large area. I wonder what’s their purpose.

  8. Very carefully.

Why do we hear so much about Mexican drug cartels but nothing about the American distributors they sell to?

  1. Drugs operate in a pyramidal fashion. The cartels are at the top. That’s where the money, guns and power resides. The people crossing the border are next down, and they have the toughest job. Next is the distributors who pass it out like middle management. Drug dealers are the bottom of the heap.

    When you hear about any big company, you usually hear about the CEO and board of directors. Sometimes upper management. How often do you hear about middle management or the cube farm workers?

  2. Simple. “Out of sight, out of mind”

    If the violence spilled over into the US, you’d hear about it real fast. American media is a selective outrage machine.

  3. The drug distributors here don’t have their own armys that they can use to take over whole towns and kill people with impunity.

  4. I asked my brother this after seeing this pop up, he’s a mere three year DEA veteran, but did just under a decade prior in a couple state vice/drug units around here… and no, I can’t prove it and if you don’t believe me, I don’t care:

    He says the immediate distributors on the American side are actually some of the hardest people to catch. Once a shipment gets past the point of entry, they pretty much won the first round – that’s why you don’t hear about a lot of drug busts happening 100 miles into the US where they get a couple big rigs or something…

    The big shipments are broken down and distributed through various channels and means to the middle-men, who are still holding considerable weight to get it down to street level. These are the folks that, per my bro, are hard to catch. The street level folks rarely dime them out, they’re usually pretty bright to get to that level and know how to distance themselves decently, etc. (edit) these people often have perfectly normal lives, at this point in the chain are still directly linked via cultural origin to the cartels (someone in their family is involved, or was, somehow – these people do not tend to be white Americans or “recruited” like mules – they are people who’ve proven themselves in some manner as being trusted as more than soldiers – this initial sale they make is where a lot of the profit sent back south is generated.

    You see lots of street level busts, lots of local supplier busts, but you hardly ever see anything between point of entry and when it gets broken down to its final distribution into a region. The “gang” leader who thinks he’s scoring weight, that guy is a chump. He’s three stops down the line from the guy getting the bricks out of the latest shipment north…

  5. Typically, they don’t kill rivals, cut them into parts, and dump them in a public place, for starters.

  6. Here is a typical pattern I see:

    Suppliers with connections in Mexico are able to supply multiple kilograms to distributors in the United States. Those types of suppliers do not generally get involved in retail sales because of the risk of getting caught. I think it is difficult to run a organized crime type large-scale drug distribution operation in the United States because law-enforcement corruption is very low compared to Mexico. If you are a drug kingpin, it makes sense to stay in Mexico and send expendable middlemen to deliver product to the United States.

    The buyers in the United States handle the retail end. Their organizations can grow, but every person you bring into your network raises the risk that someone will get caught and bring the cops down on everyone else.

  7. No one is getting their head cut off in US. People will always want drugs the war on drugs is a ruse.

  8. I saw an episode of a crime show about this guy in Kansas City who was getting millions of dollars of cocaine delivered to him from the cartels on consignment. American Gangsters, maybe. Not sure, but you could easily find it if you researched it a little.

    The cartel delivered the coke, then would smuggle the money back in cars with hidden compartments.

    > News and Press Releases
    KC man sentenced to 30 years for multi-million dollar
    Drug-trafficking conspiracy
    mexican drug cartels smuggled hundreds of kilograms
    of cocaine to KC


  9. It’s called misdirection, if we are worried about Mexico then we will worry about everything involving Mexico (kidnappings, murders, illegal immigrants) and not the shortcomings of this country.

  10. There are two kinds of drug dealers: those who need forklifts and those who don’t.

  11. CIA, FBI, DEA

    Immortal Technique gives a walk-through:

  12. In the old days there were a lot more American distributors. Then the cartels started vertical integration. A person used to be able to drive into the Mexican hinterlands and score a load of weed with little hassle. Nowadays (and even before 2007 when the current episode of violence erupted), that’s suicide.
    Much of the current one-step-up-from-retailing distribution is done by affiliated gangs. Motorcycle gangs, prison gangs, street gangs. But in some communities, the guy selling coke to your neighborhood dealer is junior level employee of a Mexican cartel.

  13. The cartels are in America too. They distribute the drugs themselves and they team up with gangs or large independent suppliers to wholesale for them out of cities like la, Denver, Chicago (big time, they use Chicago to supply the whole Midwest basically) and Atlanta, NYC, Detroit, etc. you don’t hear about lower level suppliers because they are small time and try to stay under the radar

  14. Because the people on this side are also Mexican and are either cartel members, or associates.

  15. Media bias may also be at play.

Why is it we go into a state of “feeling low” for no apparent reason sometimes and how does it pass away?

  1. Summer after Junior-year I caught a slump like this that must have last for over a month. Couldn’t figure it out until I did a little self evaluation and realized that between Closing at work (5pm-2am) Staying up partying after (2am-7am) and then crashing for most of the day (7a-3ish) I rarely even saw the sun. after a couple days of sleeping out in my hammock and soaking up some of that sweetsweet Vitamin D I was right as rain.

  2. Hormonal fluctuations. The body has a natural cycle in which hormone secretion increases and decreases for certain chemicals within the body. Increased levels of certain hormones and decreased levels of other hormones cause your mood to shift. This is why women get so sensitive during menstruation. Not a lot of people know that guys actually have these hormonal fluctuations as well and their cycles can actually sync the same way girls menstrual cycles do.

  3. It was a revelation to me to learn how our thoughts affect our ‘reality’. I always thought, “If I think it, it must be real.” But that’s not true. Thoughts are just thoughts, and they come and go on their own. So, when I start into a depressing thinking pattern, having all kinds of negative thoughts that lay me low, I now realize that I don’t have to believe the thoughts. That helps me either snap out of it, or at least realize that the thoughts will pass on their own, and I can just be patient.

  4. In my Native tradition I call this the blue wolf. It came out of seeking a private vision for my life from the Creator when I was lost and going through one my the lowest times. It was inspired by the medicine wheel teachings of my tribe and from the wisdom of my kind Elders. It saved my life, but I am not a therapist, this was my personal vision that guided me to change the entire path of my life forever. Take what you like and leave the rest. Find out for yourself. If you choose that path, you have to follow the blue wolf into the forest and see where it leads. If you try to control it your are not following. If you try to jump ahead and lead it you are not following. Follow the blue wolf and see where it leads and more will be revealed.

  5. How is your diet? That is the first thing that comes to my mind when I hear this question.

    What is a good diet constructed of? A number of important things:

    Sufficient fiber. This means plenty of vegetables, some fruit, nuts, perhaps some dried fruit. Fiber keeps the digestion system running comfortably and efficiently. By eating plenty of vegetables for fiber you are also getting vitamins that you need to feel your best.

    Plenty of water. Staying hydrated is very important to feeling at your best. Avoid soda. Soda contains salt which is added by manufacturers to dehydrate you so that you want to drink more soda. They have to add a lot of sugar to mask the salt content. Sugar spikes your blood sugar quickly and then it crashes making you feel tired within a few hours.

    Sufficient protein. Protein makes you stronger. Your muscles need protein to recover and stay strong after daily use. Remember your heart is a muscle. Meat and fish contain complete protein as does dairy and whey protein powder. If you want to avoid meat you need to combine foods such as rice and beans to get complete protein. Meat also contains vitamin B12 which is particularly important for giving you energy. Vegetarians need to supplement B12. Most people need between 50 and 100 grams of protein a day. People who are weight training often eat much more than 100 grams a day.

    Addressing food intolerances. People can be intolerant to different foods. If you have a food tolerance, avoiding that food can make an enormous positive difference in how you feel. Certain food intolerances can cause a low feeling. Some examples of food intolerances are dairy, eggs, wheat and soy. There is a lot of information online about food intolerances. If you want help finding whether you have a food intolerance a dietician (nutritionist) or doctor can help you.

    Sufficient dietary fat. To function properly most bodies need 25-35% dietary fat as a percentage of daily calories. Dietary fat gives long lasting, steady energy throughout the day. Dietary fat is needed to absorb vitamins A, D, E, K, and carotenoids. Each gram of fat has 9 calories, each gram of carbohydrates and protein have 4 calories. Your body needs dietary fat for brain development, controlling inflammation, digestion and blood clotting. Good sources of dietary fat are meat, fish, dairy, nuts, avocados, olive oil, butter. Remember that body fat is a function of total calories and level of exercise and is not the same thing as dietary fat. The fat you get from food are called essential because your body cannot make them itself, or work without them. Dietary fat adds satiety and a sense of fullness after eating a meal and also affects hormone levels. All your cells are defined by fat molecules aligned as a membrane. Dietary fat is needed to provide central building blocks to all cells in the body.

    Sufficient carbohydrates. Carbohydrates are an important source of energy. Complex carbohydrates found in rice, grains, potatoes and starchy vegetables digest more slowly and give longer lasting energy. Sugar is a simple carbohydrate. Sugar will spike your blood sugar and then you will crash. Some sugar is a nice part of a diet but too much and you will not feel your best. Too much sugar has also been linked to a number of diseases later in life. Most people need between 100 and 300 grams of carbohydrates a day and often more. If you are exercising a lot you will need to eat more carbohydrates.

    Sufficient vitamin D. Your body generates vitamin D naturally when your skin is exposed to sunlight. Spend 10-15 minutes outside in the middle of a sunny day with exposed skin to get vitamin D. This is difficult to do in the winter because often it will be overcast for weeks. Take advantage of the sun in the spring and summer by spending time outside to restore your vitamin D.

  6. There are many variables such as diet, current thoughts, current experience, location, environment, past memories, stress, amount of sleep, medication etc etc etc that affect mood (the list is virtually infinite). However, your question implies that you are simply sitting still feeling fine, while all of a sudden you feel low. It is important to note that if this scenario as you have implied plays out and persists (that is, it continues to happen) then it would be best to seek help from a medical professional (your doctor who may refer you to a therapist/psychiatrist). The professional would have a better time narrowing down the cause (whether it be biological such as a chemical imbalance in the brain, a physical defect in the brain, or whether it be psychological such as an event in your life that may be impacting your mood on a more general basis).

    As for what is happening in the brain when you feel low – there are various regions in the brain that influence mood: hippocampus, thalamus, cerebral cortex, and amygdala. No one region is responsible for mood, but each can significantly impact mood per findings from more recent brain scans – but to which extent is highly debated. From a chemical standpoint, some researchers believe that Serotonin, (a neurotransmitter in the brain essentially acting like the chemical that facilitates nerve cell firing) is under-produced. When under-produced, scientists hypothesize that the brain is more prone to psychological stress – but it remains a question of debate in regard to its role. SSRI’s or (Selective Serotonin Uptake Inhibitors) are what depression medications are – each medication has a method of either increasing the amount of serotonin in the brain, or limiting the extent by which serotonin is removed from the brain) – by doing so and regulating the amount of serotonin has shown results for patients, though the full mechanism by which SSRI’s function is still not fully understood. The observed outcome of SSRI’s suggest that once serotonin levels return back to normal levels (pertinent to that patient’s standard of normal), then depression can be eradicated or managed. It is important to note that other factors such as the stressful environment, or other environmental traumas must be addressed with the help of a professional. ‘The passing of mood’ as you state, though, is generally your brain’s serotonin level, returned to balance.

    To feel better generally, try to eat healthy foods, get lots of exercise, engage in meditation, and some studies suggest it may also help to stimulate your brain (read/movies/even games, etc). Improving your physical appearance has been shown in some studies to make you feel better naturally – take care of your body (hygeine, grooming, etc). Again, feeling down for extended periods without any obvious cause is not normal and you should seek professional help.

    helpful information:



    Telephone Hotlines:

    US Suicide Hotline 1-800-784-2433

    NDMDA Depression Hotline – Support Group 800-826-3632

    Suicide Prevention Services Crisis Hotline 800-784-2433

    Suicide Prevention Services Depression Hotline 630-482-9696

    AAA Crisis Pregnancy Center 800-560-0717

    Child Abuse Hotline – Support & Information 800-792-5200

    Crisis Help Line – For Any Kind of Crisis 800-233-4357

    Domestic & Teen Dating Violence (English & Spanish) 800-992-2600

    Parental Stress Hotline – Help for Parents 800-632-8188

    Runaway Hotline (All Calls are Confidential) 800-231-6946

    Sexual Assault Hotline (24/7, English & Spanish) 800-223-5001

    Suicide & Depression Hotline – Covenant House 800-999-9999

    National Child Abuse Hotline 800-422-4453

    National Domestic Violence Hotline 800-799-SAFE

    National Domestic Violence Hotline (TDD) 800-787-3224

    National Youth Crisis Hotline 800-448-4663

  7. 1. Emotional response.

    Smells, songs, tastes, and other ‘cues’ can bring up emotions even when we don’t clearly remember why.

    The amygdala processes emotional experiences in the brain. Stress and time can affect memory, but the amygdala will still be able to process emotions.

    2. Hormones!

    Serotonin, estrogen, and dopamine can effect mood. (Lots of hormones can.)

    As an extreme example, one reason why people suffer from PTSD is because the stress they experienced released so much dopamine that their brain became addicted to it. This makes their normal day-to-day life boring (and even meaningless) in comparison.

    But dopamine is released in the brain in our normal day-to-day lives.

    > “Inside the brain, dopamine plays important roles in motor control, motivation, arousal, cognition, and reward, as well as a number of basic lower-level functions including lactation, sexual gratification, and nausea.”

    Every time you orgasm, eat sugar, or achieve something you care about
    your brain gives you a dopamine kick. Once that kick runs out you’ll feel a bit low – and want to seek that thrill again.

    Addicted to something? Dopamine probably has a lot to do with it.

    3. Health.

    Your blood sugar levels, quality of sleep, and how balanced your diet is can affect your mood. (And pretty much anything that goes wrong in your body can make you feel like crap until your body sorts it out.)

    Even just one unbalanced meal can send your blood sugar up and down a mood-killing rollercoaster.

    ETA: Fixed formatting.

  8. For me personally, I get depressed when I’m not doing deep down what I know I should be doing.

    Therefore fruitless activities depress me such as video
    gaming too much, not lifting Weighr, not partaking in skateboarding or skiing, not learning, no goals, etc.

    People get depressed when they get stuck. They stop moving. In life, never stop moving, always better yourself and never be satisfied.
    (nothing to do with material wealth.)

  9. I know it’s been mentioned before but I want to emphasize: EXERCISE. It WILL pull you out of your slump. Take it from a guy who spent 20 years with crippling depression. My lows are manageable now, and if they start to get bad I just grab my gear and hit the gym. An hour of cardio is the best cure I’ve found for the unwarranted blues.

    You CAN do it, and it’s far, far easier than you realize. Two weeks in the gym, 3-4 days per week. By the end of the second week you’ll feel amazing.

  10. The Sweet is never as sweet… without the bitter

  11. All it takes is one negative thought … “I’m not good enough”, Then it builds up and your brain adds more and more to the mixture without you consciously being aware of it – Negative thoughts equate to low self esteem and that blip causes an immediate downer.

    The way to stop it is to analyse every positive thing thats happened to you each and every day on a list which takes 2 minutes of your time – Think about how that thing made you feel and you will emulate it.

  12. Hormones are involved but it’s more closely related to the neurotransmitters dopamine and serotonin. (Although hormone levels do interact with these chemicals so its kind of a chicken-or-the-egg question) These are both responsible for feelings of happiness and pleasure (that is a massive simplification but I’m mobile so forgive me). Many things can interact with the amount of dopamine and serotonin. Certain vitamins and proteins aide in the production and uptake of these chemicals so if your body is lacking them due to a poor diet it can cause a dip in mood. The stress hormone cortisol interferes with the production/uptake of D and S so stress can do it. Even the amount of daylight we get can influence it. In cases of seasonal depression a lack of sunlight has been indicated to lower serotonin levels which cause the “winter blues”. There is definitely more to be said on this topic and what i have said is simplified but like I said I’m mobile so hopefully that answers your question

  13. Cognition plays a key role in emotional state. Depending on ones perception of events, your point of view, then your mind will react accordingly. If one is content with his achievements and environment then the mood will be subjective to the thoughts and the way situations are perceived. If one perspective is unsatisfied with their life choices, and environment then their emotions will react accordingly.

  14. It depends on how low you mean. It bothers me that a lot of people have offered cursory advice on something that could be clinical depression. I’m not prepared to answer unless I have more information from you.

  15. Watch your caffeine intake. Most people are addicted to caffeine. 3-6 hours after consumption, a caffeine comedown makes your brain’s dopamine levels sink and this can cause depression-like symptoms for a while.

What is the Multiverse?

  1. One theory suggests that beyond the “bubble” of our universe, there is a quantum vacuum. A QV is a state in which normal laws of physics do not apply. A QV is distinct from empty space in that a QV has no properties of any kind, while empty space has several.

    In other words, in a QV, there’s no rule that says a universe can’t bang itself into existence from nothing. So the thinking goes, if the QV is the “soda,” then we and other universes might be the “bubbles.”

  2. In mathematics and physics, you can ask questions with mathematical equations or series of equations and proofs. Generally, without getting too far into it, when quantum physicists specifically address this question, the math sometimes suggests that multiple universe exist.

    It takes some imagining if you don’t understand such advanced mathematics. But generally speaking, equations tell us something about our universe, even simple ones like 1+1=2. These very clever and thorough physicists are trying to tell something bigger than that. And sometimes the math tells us that multiple universes must exist using the logic and math we understand.

  3. Way too complicated to even remotely attempt to explain at this level.

    I get ELI5, but seriously, it’s just like all guys who say “ELI5 String Theory”.

    You can’t explain this shit in layman’s terms, not one answer I see is ever adequate, and with good reason.

  4. There is a thought experiment about infinity. When i move in a straight line and i suddenly hit a wall or there is a barrier of some sort then something must behind it and if i would be able to cross that barrier and hit another one there must be something behind that too. The same applies here, our universe might have a barrier, but there must be something behind it, maybe other universes maybe something else.

    Think about a fractal, it’s infinite in complexity but its also very similar and kind of structured. Same is true for the multiple universes. They are similar but certain aspects could be different. Physical laws might be different there. Some might even only exists for a few milliseconds and then collapse. It’s a theory so it requires some form of faith in that certain assumption are correct because we have a hard time proving it true or false.

  5. If you look around you will find things don’t generally come in ones, that is there is only one of you, but there are many, many other people, and planets and stars and galaxies. Our intuition tells us that there ought to be other universes, likely an infinite number of them. As for the Big Bang and the episode of Cosmos that you referred to, a black hole is thought to contain a singularity, that is all the matter and energy that went into making the black hole is concentrated into a mathematical point. A mathematical point has zero volume (by definition) and therefore a singularity tries to crush things beyond the limits allowed by quantum theory. So it may be (not proven, not yet well thought out!) that quantum mechanics creates a new universe via a big bang when the originally forming black hole threatens violence to the quantum theory. Many, many questions remain: is there only one size of universe?, are the physical laws of each universe different?, can communication happen between parent and child universe? can we figure out how to demonstrate the truth or falsity of this idea?

    As to the claim that we think the multiverse exists because it works in the math, you can make math say many things that are not true about this universe for the simple reason that math is infinite, reality is not.

  6. The multiverse, in some theories, such as M-theory and brane cosmology comes from the idea of a bulk of (mem)branes. If two branes touch then a big bang forms. The muliverse for the most part is an abstract space where the concept of distance as we know it is not relevant, but it can be visualised as a frothy surface in which universes pop into and out of existance.

    Depending on the ‘configuration’ of the ‘branes’ some universes are stable and some are not, we are in a stable one, but there could be other universes that are less stable or have mostly space in them with little to no matter. Our universe might be pushing against these other universes.

    Astrophysicists are not sure if it exists but the recent observation of gravitational waves provides a starting point. If for example more measurements are made and it is noticed that the wave pattern is not even or regular, for example there is big gap in some places and not in others, that gap would need to be explained. One way of explaining it would be that the universe ‘bumped’ up against something during the inflationary period of the big bang pushing away the gravitional waves.