The Fallout world is an anachronistic setting that diverged from our own sometime after World War II. The base concept for the setting is a 1950s World of Tomorrow, a future as envisioned through the lens of the Atomic and Jet Ages. The Fallout world is more or less what Americans of the 1950s thought things would be like in a future decimated by nuclear war. As such, science also works a little bit different in the setting.
 World of Tomorrow
The Fallout world is home to hovering housecleaning robots, and the use of laser guns is the norm. Automobiles look like Motorama concept vehicles from the 1950s: massive tail-finned and chromed behemoths, yet powered by nuclear fusion engines. While there are many desktop computers similar to our own (albeit on a par with those which became available to us in the 1980s, with monochromatic screens and apparently tiny memory capacities), the major computers are still giant banks of machines and use reel-to-reel tape storage. However, the pinnacle models are somehow more powerful than our universe's supercomputers. Clothing styles, architecture, building interiors and furnishings remained heavily influenced by the culture of the American 1950s, and popular styles of this period such as art deco, googie, and futurism – collectively known as Raygun Gothic – remained prevalent. Posters and signage also largely hearken to this decade. Radio, rather than television, remains the most common mass media, and food products are based on those popularized in the TV-dinner era (i.e. boxed macaroni and cheese, canned meat, freeze dried pre-packaged foods, Salisbury steak TV dinners, et cetera).
Instead of working to develop miniaturized electronics, post-World War II humanity in the Fallout world invested its technological efforts in massive supercomputers (e.g., ZAX supercomputers), further harnessing the atom, inventing compact nuclear fusion power generators and an enhanced and miniaturized form of nuclear fission, as well as more advanced robotics, cybernetics and genetic engineering than we currently possess in our universe. This meant that things like power armor and laser weaponry could be built, as well as the large number of housekeeping robots used by many Americans before the Great War. Many such power sources continue to function hundreds of years after their construction.
A demonization of communism and McCarthyism, common to both worlds during the 1950s, remained a part of everyday North American life in the Fallout world. The communist Chinese became the main affront to democracy in the Fallout universe, which partially fueled the Sino-American War and ultimately, the Great War itself.
 Historical divergence of the timelines
The historical details of the Divergence and the exact moment when it occurred are unknown. What is known is that it happened at some point after 1945. The date is hard to pin down, because, even after the Divergence, the two timelines are not entirely different. While it may have developed concurrently, America saw a counterculture similar to the one in the 1960s; while the term 'hippie' still appears in the wasteland and existed as early as 1945, it didn't enter the popular American lexicon until the 1960s in our reality. Clearly, in the Fallout world, something similar to the rise of anti-war hippie culture in our world also occurred.
There are several notable differences between the politics in the Fallout world and our own.
 United States politics
The United States of America itself changed drastically after the divergence of the timelines, evidenced by the American flag. Sometime between 1945 and 1969, the 50 states were consolidated (and in California's case, split up) into 13 commonwealths, although it appears that the states themselves retained some degree of sovereignty.
United States government was still driven by a two party system between Republicans and Democrats. A few presidents also served concurrently with our timeline. Richard Nixon held office at some point and had the same unsavory character regardless. Ronald Reagan also held office and headed reforms for a more prosperous and growing economy.
Civil rights appear to have made at least some progress, as minorities and women could serve in unsegregated divisions of the military. However, women were still seen as the classical homemaker and primarily worked outside of the home in "feminine" jobs like nursing, teaching and secretarial work. However, after the Great War, race and sex have little to do with how one lives. Survival is of the utmost concern and most post-apocalyptic societies could not care what someone looks like as long as they are helpful; however, notable exceptions of this paradigm include the eugenics promoted by the Enclave, and the misogyny within Caesar's Legion.
 World politics
The Union of Soviet Socialist Republics is still a political entity by the time of the Great War. In our world, the U.S.S.R. was dissolved in 1991, with Russia and the various Soviet satellites becoming independent nations once more.
The People's Republic of China still resembles the China of our world during Chairman Mao's rule, and it seems that the country never experienced the liberalization and free market reforms that it did in our world after the United States reproached the Beijing government in the 1970s.
 City design and architecture
City design in the Fallout world differs from that in ours. Washington, D.C., for example, looks similar to the American capital city of our world in terms of the placement of signature buildings and overall urban design, but has some noticeable changes. Much of the pre-Great War contemporary architecture is 1940s/50s art deco and 1950s/60s modernist; the skyscrapers that define Arlington, Virginia in our reality do not exist; buildings such as the Smithsonian National Air and Space Museum are replaced with the Smithsonian Museum of Technology; and busts of persons apparently famous in the Fallout world while unknown in ours are located on many buildings. Many buildings and memorials built since the 1950s and 1960s in our timeline (such as the Vietnam War Memorial, the World War II Memorial, Nationals' Park, the Kennedy Center and the Newseum) either were never built or were destroyed and totally forgotten. Factories remain fairly common, as was the case during the American industrial economy of the 1940s-1960s, and, while heavily automated with robotics, are still quite primitive by our present-day standards.
 Computers that fit in a single room!
One of the major divergences from our own history is that, in the Fallout world, the rapid miniaturization of digital computers and electronics never occurred. The transistor, invented in our world in 1947, was not developed in the Fallout universe until the decade just before the Great War in 2077, while its successor, the semiconducting microprocessor chip, may have never been developed at all. As a result, the digital computers in Fallout are all of the old reel-to-reel tape type that take up large amounts of room. The mixed vacuum tube/transistor personal computers used on desktops are very large and bulky, while displays are small monochromatic cathode ray tubes rather than the liquid crystal flat panel displays now common in our own universe. Data is stored on holotapes or holodisks which electromagnetically store information as three-dimensional digital images. These computers are very advanced in their processing power, indicating that progress continued in computer science (albeit at a slower rate than in our universe), but the technology to make them smaller never emerged as did not user-friendly icon-based graphical user interface (GUI) operating systems, which first appeared commercially in our world in the 1980s. UIs remained fairly basic command-line affairs, and less frequently advanced voice interfaces (as per computers in 1950s science fiction) were developed for computer systems which made a GUI redundant on such systems.
However, even though computers remained rather large and clunky, complex artificial intelligence units were developed. The AIs that have appeared in Fallout games have shown to be rather advanced and possess creativity, desire, and, in many cases, emotion.
Television sets and radios also failed to evolve past the early 1960s level, and television in the Fallout universe remained in the same monochromatic hues as its computer screens. Another example of technology failing to evolve can also be found in cameras. Cameras in the Fallout universe are big and bulky with large flash bulbs like those used in the late 1950s and '60s. Interestingly enough, however, the CCTV cameras seen in Fallout games are just as compact as those in the real world.
Androids like those found in the Capital Wasteland would undoubtedly require miniaturized electronics in order to function. Whether this technology was limited to the possession of the scientists working at the organization known only as the Institute and its location in the Commonwealth is unknown.
Various references to uploading and downloading, as well as to e-mail and networked communications, also demonstrate that though the Fallout universe lacks our mastery of microprocessor technology, other aspects of computer science proceeded unhindered, such as robotics, the development of the Internet, and orbital communications satellites.
 Harnessing the Power of the Atom
In the Fallout world, nuclear power was not only used for atomic bombs. It was also harnessed in nuclear reactors, which became a prominent source of energy. Large scale fission reactors that powered whole towns as in our world existed, but were a lot more common. These power plants were smaller and they often existed underneath towns and cities, such as the one in New York that almost went into meltdown and the powerworks beneath Olney, Maryland. But similar to our world where more priority was put towards making electronics smaller, more priority was put towards making nuclear reactors smaller in the Fallout universe.
They were reduced in size to the extent that they could be used in roles more typically occupied by internal combustion engines in our world, such as car engines and small electrical generators, or even in nuclear fission batteries. Controlled nuclear fusion, a source of energy which is yet to be harnessed by scientists of our world, was developed. Since 2066, fusion reactors had been used to power vehicles and, like fission reactors, were reduced to very small sizes for use in power cells which were the standard for powering medium energy weapons in the military. The general public attempted to incorporate fusion power into its infrastructure, but the process was too slow to supply power to the regions that needed it. Many of these pre-War power sources are still functioning around the late 23rd century.
This nuclear obsession of the Fallout world saw nuclear energy and, to a lesser extent, radioactive materials, being utilized wherever possible; radioactive isotopes were even added to Nuka-Cola at one point despite the inevitable health risks of ionizing radiation. Their world's obsession with nuclear energy ultimately ended in the destruction of pre-War society.
Along with this proliferation of nuclear technologies came the risk of radiation poisoning during accidental radiation exposure. In response to this threat, radiation treatment and inoculation technologies were developed in the Fallout universe. Such technologies have yet to be realized in our timeline beyond very early experiments.
In the Fallout world, robotics had advanced way beyond our world's understanding. So much so in fact that robots had been constructed for many purposes from simple helping hands and butlers to construction and full-fledged military combat robots, and many examples survived long enough to be a factor in the Fallout world.
Typically, robots are equipped with a basic programming structure that dictates behavior and priorities. In most cases, these rules are effectively set in stone. However, robots can also develop personalities or come pre-equipped with and AI. Some robots, such as the Nuka-Cola shipping foreman appear to have rather harsh personalities present from their first days of activation, while others, such as the protectron series seem to have little personality at all. At times, this personality seems to operate at odds with the fundamental core programming of the robot. In fact, combat inhibitors are fitted on almost all robots to stop them from acting violently on humans as most robots who have a personality seem to an adverse attitude and an urge to kill any humans and anything living. With this in mind, it can be safe to say that robots of the Fallout universe do not follow Asimov's three laws of robotics, or, if they do, very loosely.
Androids also exist in the Fallout universe, but did not exist before the Great War and were solely the invention of the Commonwealth. Unlike robots, androids have advanced personalities able to display a wide range of emotions and feelings without being unwarrantably violent like robots. Androids can also learn and keep personal memories and feel pain unlike robots.
 Military technologies
All of the Fallout games use a combination of fictional weapons and weapons similar or identical to real-world examples. The games vary in their faithfulness to canon and logic in their choices of which weapons are included as well as in how the weapons' characteristics have been modified from their real-world counterparts.
 Nuclear weapons
The development of nuclear weapons in the Fallout world differed from our universe in that aircraft-delivered nuclear bombs were not phased out of use and intercontinental ballistic missiles in underground silos were developed alongside the use of Fat Man and Little Boy-style aerial warheads. It is suggested that nuclear-capable countries, such as the U.S. and China, had begun converting their nuclear stockpiles to ballistic missile form by the time of the Great War in 2077. Although electronic miniaturization was accomplished in the Fallout universe, nuclear bombs of the late 21st century still retained the Fat Man-esque shape.
 Projectile firearms
Assault rifles retained designs of weapons that originated in the 1940s and 1950s, such as the AK-47 or G3. There is evidence that, despite the diverging timelines, weapons development in the Fallout universe followed a similar path to ours. Picatinny rails, an equipment system that is only recently been implemented in our universe, as well as weapons such as the China Lake and M79 grenade launchers, which were developed around the 1960s for the Vietnam War in our timeline. Handguns also retained similar designs to those of the early 20th century with notable exceptions, such as SIG-Sauer pistols. Heavy weapons, such as missile launchers and the Fat Man, had unique designs such as side mounted foregrips and pneumatic ammunition loading systems. Weapons that seem impractical in our timeline, such as nuclear catapults and man-portable miniguns, were extensively developed in the Fallout timeline and issued to frontline troops. Ammunition calibers that are not common in our timeline, such as the .32 caliber and 10mm, are widely used in the Fallout era, while common ammunition in our timeline, such as .50 BMG, .45 ACP, etc. are rare or nonexistent.
 Energy weapons
We often develop technology not because it's great immediately, but because developing that technology helps us move toward its potential. We've had various forms of hybrid vehicles (gasoline combustion engine + ???) around for a long time. Most of them were pretty bad and impractical. We've had biofuels around for a while, but most of those are STILL bad and/or impractical. We saw tanks developed in WW1 that were absolute garbage.
All of those things were kind of crummy for a while, but if we hadn't gone through the stage of "Yeah... this is... okay, I guess," we would never have reached the subsequent stages. Coil/rail gun technology used to be completely impractical. Now it's reached the stage where maybe/sorta we could mount an enormous one on a destroyer and blast through a bunker with a huge slug from miles away. We're probably not going to have Eraser- or Fallout-style Gauss rifles for a while, but we see the potential.
In the Fallout universe, I think that the military appeal of weaponry that uses a small number of more-or-less universal ammunition types would be great. Today, we have NATO standards so that allies armies can share ammunition. But what if you could use the same ammunition type for powering a sniper rifle that you'd use for a devastating close-range weapon (e.g. a Microfusion Cell powering a Laser Rifle or a Plasma Rifle)? For a military force in the field, the flexibility of that would be immense.
Anyway, I considered the EWs in F:NV to have reached the point where they were starting to replace conventional weapons, but had not yet completely eclipsed them -- sort of like the early days of firearms, when they were still being used concurrently with bows.”— J.E. Sawyer on energy weapons in the Fallout universe
Unlike in our world, handheld laser, plasma, and pulse weapons exist in the Fallout world and are capable of burning targets to a pile of ash or into a liquefied puddle. Laser and plasma weapons in the Fallout world are far more advanced then anything our universe has made where the most advanced laser weapons made either never worked, are non-lethal crowd control, or too large to be used as anything other than large-scale defense. Also, because of the emphasis to advance laser and plasma weapons, miniaturization of laser and plasma weapons occurred. There is also evidence of alien energy based weapons such as alien blasters or the famed "death ray" of 1950s pulp fiction and B-movies.
 Orbital weapons
The Fallout universe has three prime examples of orbital weapons. An operation orbital missile platform in the Capital Wasteland which can be used via a terminal at a satellite station; the Enclave's Bradley-Hercules, a high explosive missile based orbital platform; and the laser-based Archimedes II being experimented with at Helios One; all of these target a position on the surface and can take out any threat.
An example of a real-world orbital weapon system was the Soviet 8K69 Fractional Orbital Bombardment System, which placed a nuclear missile re-entry vehicle into low-earth orbit for an indefinite period of time and range, able to launch a strike with unprecedented speed similar to the Enclave's fictional Bradley-Hercules platform. FOBS was phased out in 1982 in compliance with the now-defunct SALT II treaty, which forbade deploying WMDs into Earth's orbit.
 Other Technologies
Aircraft are not frequently found in the Fallout universe but there is evidence their designs have not changed remarkably since the immediate post-World War II era of the late 1940s and early 1950s. Jet propulsion has been fully developed in the Fallout universe, as the Chinese bombers and American fighters are jet powered.. Despite the development of jet power, some planes still use propellers.
Prosthesis in the Fallout universe is fairly uncommon, but evidence of its existence has been in every Fallout. From what can be seen from shown prosthetics in the Fallout universe, the science of prosthesis has advanced well beyond our world's understanding, able to mechanically replacate the human hand with articulate joints allowing for a high freedom of movement. Other achievements that have yet to be achieved by our world are the entire enhancement of the human body with implants which can accelerate muscular growth and enhance agility to improving cognition and accelerate cell growth to replace damaged tissue.
Another technological difference between the Fallout universe and our own is the approach taken to plastic polymer use. Plastics are generally manufactured with petroleum but due to the diminishing petroleum supply during the 2050s and onward, less and less plastic were manufactured and glass and metal alloys became the materials of choice. Syringes are glass and reusable, stimpaks come in a glass vial inside a metal casing, et cetera. Although water seems to come in plastic Polyethylene Terephthalate (PET or PETE) bottles, the shape and size of the bottles themselves suggest they are mainly part of laboratory equipment. However, the American military has widely employed plastic polymers – military combat armor is made of advanced defensive polymers, as is the T-51b power armor and later power armor models in the line.
 Physics in a different universe
The laws of physics in the Fallout universe are different in certain aspects from our own, bent to reflect the Science! of 1950s pulp science fiction rather than actual 20th and 21st century science. In our world, we know that exposure to high levels of ionizing radiation leads to radiation sickness, cancer, and other deadly conditions. In the Fallout world, however, severe radiation exposure is not always fatal, and it occasionally produces mutations including increased size and, in the case of ghouls, extremely long life span and increased physical durability coupled with an externally decaying body. Classic 1950s horror movies like Them! or Attack of The 50 Foot Woman, in which freak nuclear accidents caused giant ants or people to appear, are good examples of the Fallout universe's whimsical take on basic scientific principles.
- Fallout Bible 6 Questions I will not answer: "3. What was U.S./world history like before the timeline included in previous Fallout updates?"
"No one has asked this yet, but I thought I would cut this question off at the pass. Fallout takes place on a future earth, in an alternate timeline. I will not be including any information on how and when it diverged - it will remain one of the mysteries of the setting. Just let it be known that it diverged after WW2, and leave it at that."
- Raygun Gothic
- Radios are found more prominently in post-apocalyptic homes than television sets
- Certain residents of Megaton in Fallout 3 occasionally utter the phrase, "Don't let them fool you with their hippie crap"; graffiti on the outside of the Hidden Valley bunker in Fallout: New Vegas; the hippie commune present before the Great War in Hopeville and Ashton.
- Etymology of Hippie on Wikipedia
- The Nevada state flag waves outside of Doc Mitchell's home and the license plates in the wasteland are adorned with state names rather than commonwealth names.
- Jack Smith's dialogue: "Yessir, it's every American's civic duty to cast his vote for his favorite Republican candidate. Am I right?"
"Now, now, my vote is my business and no one else's. But I'll tell you one thing: we didn't vote for any beatnik liberal commies, that's for sure."
- The Mr. Nixon doll advises that it is "best to lie."
- Sierra Depot GNN transcript: "...The US economy is seeing it's greatest growth since the Reagan Era."
- Presence of African-American, Asian, Latino and women soldiers during the Anchorage Reclamation simulation
- File:Fo3 Loading 20.png
- Fallout Bible 0 Timeline repair: "June 2065 Due to enormous demands for electricity in the summer of 2065, a nuclear reactor in New York City almost goes critical. The near meltdown brings into effect power rationing, and the term "Hot Summer" is used to refer to the New York incident."
- Fallout Bible 0 Timeline repair: "Summer 2066 Adding further insult to the Chinese-American relations, the first crude fusion cell is unveiled, one of the results of the Power Armor project. Devices designed for the fusion cell begin to be manufactured. Incorporating fusion power into the general US infrastructure begins, but the process is too slow to supply power to the regions that need it. Nearly thirteen years later, few sections of the United States were supplied with fusion power."
- Presence of RadAway and Rad-X, treatment and inoculation technologies, respectively
- Experimental Treatments for Radiation Poisoning
- Fat Man/Little Boy-style bombs are present in Fort Constantine as is the Minuteman ICBM with missile silo doors. Other areas, such as Fort Bannister and the Wheaton Armory, also have missile silo doors.
- Robert House's dialogue: "On the day of the Great War, 77 atomic warheads [ICBMs] targeted Las Vegas and its surrounding areas."
- Museum of Technology Delta IX rocket information: "...The Delta IX was in use for almost 15 years before being converted for military use and having the crew and instruments sections replaced with a nuclear warhead..."
- Anchorage Reclamation simulation
- Large jet engines comprise Megaton's construction
- Aircraft at Camp McCarran in Fallout: New Vegas.
- Combat armor (Fallout) item description: "High tech armor, made out of advanced defensive polymers."
- Power armor specs