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83

Why were there no nuclear detonations in 1959? The reason there were no tests in 1959 was that the Soviet Union, Great Britain, and the United States agreed to a moratorium on nuclear weapon tests in 1958. This moratorium lasted from November 1958 to August 1961. The Soviet Union resumed on 1 September, 1961, with the US following suit a couple of weeks ...


71

The official designation for that particular device was the RDS-220. The nickname Tsar Bomba was an appellation applied by the West, rather than the designers of the bomb (who - according to the site linked above - apparently referred to it as Big Ivan, or simply the Big Bomb). According to the information on nuclearweaponarchive.org, The nickname Tsar ...


67

Because no one in their right minds would think Britain should use a weapon of mass destruction on Argentina over the Falklands, what with its 1600 population. Even then the well documented concept of a nuclear taboo was in effect. No one regarded nuclear bombs as normal bombs, and therefore no one wanted to use it so casually. The Falkland Islands were not, ...


52

It was Project Chariot, in Alaska. A good book about it is the Firecracker Boys, I recommend you read it if you are interested in the subject. I think it was cancelled because conservationists and Alaska Natives brought it to the attention of the general public, and it would have been a disaster. The proponents were perfectly willing to try it (they had ...


43

In Russian Language the word "Tsar" has also another, non-literal meaning. Examples are: "Tsar-pushka" (king of the guns), the largest (in caliber) existing gun, and "Tsar-kolokol" (king of the bells), the largest bell in the world. Both the gun and the bell are currently in the publicly accessible part of the Kremlin, (and were there during the last two ...


43

If the bomb failed to explode in any way (which was unlikely, see comments and Mark's answer), the USA still would not have to worry about it (too much). They would win the war anyway within a few months, and pick up the wrecked bomb from wherever the Japanese had stored it. Even if Japan could figure out what that bomb was supposed to be doing and repair ...


41

The primary contingency plan was the design of the bomb itself. Little Boy was not a safe design: any number of unplanned events could cause a detonation. Foremost among these is impact: a 500 g impact, such as would happen after a 15,000-foot (4.5 km) fall, is sufficient to bring the bullet and target together, detonating the bomb. If the bomb hit water ...


40

Hiroshima, the first city, was "an important army depot and port of embarkation in the middle of an urban industrial area. It is a good radar target and it is such a size that a large part of the city could be extensively damaged. There are adjacent hills which are likely to produce a focussing[sic] effect which would considerably increase the blast damage. ...


38

There was discussion of options. The "gadget" was an atomic bomb. From the minutes of the Target Committee for 10 May 1945: Gadget Jettisoning and Landing A. It was agreed that if the aircraft has to return to its base with the gadget and if it is in good condition when it has reached there, it should make a normal landing with the greatest ...


37

The US did not resort to using nuclear weapons in Vietnam for a variety of reasons: fear of the damage it would cause to the US's international reputation, domestic political considerations, a reluctance to break the 'tradition' of non-use, and a realization that, although there were plenty of viable targets such as airfields, ports and supply lines, only ...


33

The effects of Hiroshima and Nagasaki run quite deeply. One of the most profound effects is that Japan is very pacifistic and one of the few (if not the only country) that has outlawed war. Article 9 of the Japanese constitution prohibits the Japanese government from declaring war, although permits Japan to maintain a self-defense force. Since the end of ...


31

Little Boy detonated at ~580 metres above Hiroshima, and Fat Man at ~500 metres above Nagasaki. While all nuclear explosions generate electromagnetic pulses of some sort, at these low altitudes their strength rapidly diminishes with distance, giving them a rather limited area of effect. The effects of EMP from a surface or low-altitude nuclear burst will ...


30

The discovery of uranium fission by Otto Hahn and Fritz Strassmann (German chemists) in the Jan 1939 issue of Die Naturwissenschaften (The Science of Nature) sparked great interest among physicists all around the world. Jewish Hungarian born physicist Leó Szilárd was among them. Szilárd living in the US at the time, realized the importance of neutron-driven ...


28

The U.S. likely did not target Tokyo for the atomic bomb strikes as it was the seat of the Emperor and the location of much of the high ranking military officers. These are precisely the people you do not want to kill if you want to negotiate a surrender, as they are the people you would be negotiating with. The U.S. decided to drop the bombs onto military ...


27

By the time of the Vietnam war, the US nuclear weapons policies had changed radically from the mid-1950s (when nuclear weapons were seen as the logical option for ALL conflicts), and were considered viable only as a last resort and as retaliatory weapons in case an enemy would use them (or other weapons of mass destruction) first against the USA or a NATO ...


26

Not Canada, but Alaska. In 1958 "Project Chariot" was the idea to use several nuclear explosions to build a harbour at Cape Thompson, Alaska. It was part of a series of ideas to use nuclear explosions for non-military, commercial purposes. The series was called "Operation Plowshare". Wikipedia: Project Chariot Operation Plowshare


24

About the Yasukuni Shrine part of the question, since no one has addressed that: It is important to remember the nature of that establishment. The Yasukuni Shrine houses over 2.4 million of Japan's war dead, only 0.043% of whom (1,068) are convicted of any war crimes. They weren't even all members of the Japanese military. Those commemorated at the shrine ...


24

The driving force behind the Manhattan Project was less about using an atomic bomb and more about getting one before the Germans did. It was known the Germans had their own atomic bomb project and prominent physicists, including Einstein, warned the US government about the possibility of such a bomb. This was the driving force behind the Manhattan Project: ...


24

I think we may be operating from a misconception, that the diary entry concerning that the 'target will be a purely military one' and that the statement that 'Hiroshima, a military base' imply Truman did not understand the presence of a city. The target selection process had been going on for some time. A lot of documents are available and the discussion ...


23

This is not possible. And this has nothing to do with the actual brightness of explosion. A similar explosion on the Moon will probably be visible from the earth if the weather conditions are good and if you know when and where to look. According to the Wikipedia, the Nagasaki bomb was exploded at the height of 503 m, about 1/2 km. To be directly visible ...


23

This question has been debated for a very long time, and I've never seen a conclusive answer one way or the other. I don't believe there is a single reason Japan surrendered. Rather there was a long series of defeats leading to a war they could not win. Two major blows hammered the point home and a year of even greater insanity (the invasion of Japan) was ...


21

From the notes of the first Target Committee meeting (spring 1945) Tokyo is a possibility but it is now practically all bombed and burned out and is practically rubble with only the palace grounds left standing. Consideration is only possible here. The same was true of most Japanese cities. From The making of the atomic bomb. The committee had refined ...


20

A team of researchers at the Institute for International Studies at Stanford University compiled the "Database on Nuclear Smuggling, Theft, and Orphan Radiation Sources" (DSTO) in 2002. At the time, that database was described as the: "... most reliable currently available data on illicit trafficking of weapons-usable nuclear material" Lyudmila Zaitseva ...


19

At that time, the US was concerned that a repeat of the Korean war could happen, with China sending in masses of troops... North Vietnam shares a border with China, just like North Korea. China wasn't overly fond of N Korea or Vietnam (in both cases, the initial supporter was the Soviet Union, not China), but when UN forces got near the Chinese border in N ...


18

The unfortunate addition of the word "perfectly" before aware means no, and it really depends on who you define as "decision makers" and what you mean by "aware". First off, here is a great academic (but highly readable) blog run by a guy named Alex Wellerstein with lots of discussion about nuclear weapons in general, but with lots of emphasis on the ...


17

It depends on what you consider worse. Time magazine lists an incident that occurred on December 18 1970 at Yucca Flat Nuclear Test site where radioactive debris from the underground test of a 10 Kiloton Nuclear detonation was vented into the surrounding atmosphere. However the Department of Energy stated afterwards that the 86 workers who were exposed did ...


17

The project that Scott Manley is referring to was known as Project A119, and was run at the Armour Research Foundation (ARF), which was based at the Illinois Institute of Technology. The ARF is now known as the IIT Research Institute. The official title of Project A119 was A Study of Lunar Research Flights, and Volume 1 of the report, produced in 1959 by ...


15

My understanding is that the Electromagnetic Pulse induced by a nuclear weapon is mainly due to the ionizing effect of the gamma rays released by the nuclear reaction. However, for this ionizing effect to produce a downward blast of electrons moving at relativistic speed to the ground (the cause of the voltage shock on the ground), the ionizing effect has to ...


13

The link provided by @T.E.D. combined with the observations of Major Charles Sweeney that the height of the flash, off the cirrus clouds over Nagasaki, was "at least 6 miles (or 31,000 feet) [above the explosion]" giving a refraction-free visibility for such a reflected flash as about 230 miles or 370 km. The underside of the great clouds over Nagasaki ...


13

The existing answers do a good job of explaining why the EMP effect radius was not as large, but there's another important aspect we need to consider: We're talking about 1945. EMPs do affect anything electronic to some extent, but they primarily affect sensitive electronics, especially miniaturized electronics like what we use today. The voltages that are ...


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