The atomic bombing of Nagasaki, Japan on August 9, 1945

A mushroom cloud is a distinctive mushroom-shaped cloud of smoke, flame, or debris resulting from a very large explosion. They are most commonly associated with nuclear explosions, but any sufficiently large blast will produce the same sort of effect. Volcano eruptions and impact events can produce natural mushroom clouds. Image File history File linksMetadata Download high-resolution version (1246x1468, 760 KB) if you look closely, you can see a japanese person in the bottom right corner TITLE: Mushroom cloud CALL NUMBER: POS 6 - U.S., no. ... Image File history File linksMetadata Download high-resolution version (1246x1468, 760 KB) if you look closely, you can see a japanese person in the bottom right corner TITLE: Mushroom cloud CALL NUMBER: POS 6 - U.S., no. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the epicenter. ... Nagasaki ) ( ) is the capital and the largest city of Nagasaki Prefecture in Japan. ... is the 221st day of the year (222nd in leap years) in the Gregorian calendar. ... Year 1945 (MCMXLV) was a common year starting on Monday (link will display the full calendar). ... For other uses, see Mushroom (disambiguation). ... hello--~~~~fake <gallery> poos[[kill]] </gallery> For other uses, see Cloud (disambiguation). ... This article does not cite any references or sources. ... Flame generated by the burning of a candle. ... Debris (French, pronounced (IPA) dibri) is a word used to describe the remains of something that has been otherwise destroyed. ... It has been suggested that Nuclear explosive be merged into this article or section. ... For other uses, see Volcano (disambiguation). ... Artists impression of a major impact event. ...

Mushroom clouds form as a result of the sudden formation of a large mass of hot low-density gases near the ground creating a Rayleigh-Taylor instability. The mass of gas rises rapidly, resulting in turbulent vortices curling downward around its edges and drawing up a column of additional smoke and debris in the center to form its "stem". The mass of gas eventually reaches an altitude where it is no longer less dense than the surrounding air and disperses, the debris drawn upward from the ground scattering and drifting back down (see fallout). RT fingers evident in the Crab Nebula Hydrodynamics simulation of the Rayleigh-Taylor instability [1] The Rayleigh-Taylor instability, or RT instability, occurs any time a dense, heavy fluid is being accelerated by light fluid. ... Fallout is the residual radiation hazard from a nuclear explosion, so named because it falls out of the atmosphere into which it is spread during the explosion. ...

The largest mushroom clouds to be photographed resulted from the impact of fragments of Comet Shoemaker-Levy 9 on the planet Jupiter, some of which rose hundreds of kilometers above the cloud layers. Hubble Space Telescope image of Comet Shoemaker-Levy 9, taken on May 17, 1994. ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ...

Name

A large bellows creates a mushroom cloud at the Exploratorium in San Francisco, California.

Although the term "mushroom cloud" itself appears to have been coined at the start of the 1950s, mushroom clouds generated by explosions were being described before the atomic era. For instance, The Times published a report on 1 October 1937 of a Japanese attack on Shanghai in China which generated "a great mushroom of smoke". During the Second World War, descriptions of mushroom clouds were relatively common. ImageMetadata File history File links Download high resolution version (1600x1200, 385 KB) File links The following pages link to this file: Mushroom cloud Exploratorium ... ImageMetadata File history File links Download high resolution version (1600x1200, 385 KB) File links The following pages link to this file: Mushroom cloud Exploratorium ... A large bellows creates a mushroom cloud at the Exploratorium in San Francisco, California. ... Smoke billows at the exploratorium The Exploratorium is a public science museum located in the Marina District at the Palace of Fine Arts in San Francisco, California. ... “San Francisco” redirects here. ... The 1950s decade refers to the years 1950 to 1959 inclusive. ... The Times is a national newspaper published daily in the United Kingdom since 1788. ... is the 274th day of the year (275th in leap years) in the Gregorian calendar. ... Year 1937 (MCMXXXVII) was a common year starting on Friday (link will display the full calendar) of the Gregorian calendar. ... For other uses, see Shanghai (disambiguation). ... Mushroom cloud from the nuclear explosion over Nagasaki rising 18 km into the air. ...

The original descriptions of the first nuclear test explosion at Trinity Site contained many different associations with the cloud which formed after the blast, including a "multi-colored surging cloud," a "giant column," a "chimney-shaped column," a "dome-shaped" column, the "parasol," the "great funnel," and "geyser," the "convoluted brain," and even the "raspberry." In his official (then classified) description of the test, Enrico Fermi mentioned "a huge pillar of smoke with an expanded head like a gigantic mushroom".[1] The Trinity test was the first test of a nuclear weapon, conducted by the United States on July 16, 1945 at , thirty miles (48 km) southeast of Socorro on what is now White Sands Missile Range, headquartered near Alamogordo, New Mexico. ... Cultivated raspberries The raspberry (plural, raspberries) is the edible fruit of a number of species of the genus Rubus. ... Enrico Fermi (September 29, 1901 – November 28, 1954) was an Italian physicist most noted for his work on the development of the first nuclear reactor, and for his contributions to the development of quantum theory, particle physics and statistical mechanics. ...

Ascending cloud from Redoubt Volcano from an eruption in 1989. The mushroom-shaped plume rose from avalanches of hot debris (pyroclastic flows) that cascaded down the north flank of the volcano.

The atomic bomb cloud over Nagasaki, Japan was described in The Times of London of 13 August 1945 as a "huge mushroom of smoke and dust." On 9 September 1945, the New York Times published an eyewitness account of the Nagasaki, Japan bombing, written by William L. Laurence, the official newspaper correspondent of the Manhattan Project, who accompanied one of the three aircraft that made the bombing run. He wrote of the bomb producing a "pillar of purple fire", out of the top of which came "a giant mushroom that increased the height of the pillar to a total of 45,000 feet." (A similar phenomenon can be seen in the picture of the Nagasaki bomb cloud shown above.) Image File history File links Download high resolution version (1024x689, 149 KB) Picture of Mount Redoubt Eruption Ascending eruption cloud from Redoubt Volcano as viewed to the west from the Kenai Peninsula. ... Image File history File links Download high resolution version (1024x689, 149 KB) Picture of Mount Redoubt Eruption Ascending eruption cloud from Redoubt Volcano as viewed to the west from the Kenai Peninsula. ... Mount Redoubt is an active volcano in the Aleutian Range on the Alaska Peninsula in Alaska, at 60°29 North 152°45 West. ... Year 1989 (MCMLXXXIX) was a common year starting on Sunday (link displays 1989 Gregorian calendar). ... Megane-bashi, the Eyeglasses Bridge Nagasaki (&#38263;&#23822;&#24066;; -shi) is the capital and the largest city of Nagasaki Prefecture located at the south-western coast of Kyushu, Japan. ... The Times is a national newspaper published daily in the United Kingdom since 1788. ... is the 225th day of the year (226th in leap years) in the Gregorian calendar. ... Year 1945 (MCMXLV) was a common year starting on Monday (link will display the full calendar). ... is the 252nd day of the year (253rd in leap years) in the Gregorian calendar. ... Year 1945 (MCMXLV) was a common year starting on Monday (link will display the full calendar). ... The New York Times is an internationally known daily newspaper published in New York City and distributed in the United States and many other nations worldwide. ... Megane-bashi, the Eyeglasses Bridge Nagasaki (&#38263;&#23822;&#24066;; -shi) is the capital and the largest city of Nagasaki Prefecture located at the south-western coast of Kyushu, Japan. ... William Leonard Laurence (March 7, 1888–March 19, 1977) was a Lithuanian-American journalist known for his science journalism writing of the 1940s and 1950s while working for the New York Times. ... The Manhattan Project resulted in the creation of the first nuclear weapons, and the first-ever nuclear detonation, known as the Trinity test of July 16, 1945. ...

Later in 1946, the Operation Crossroads nuclear bomb tests were described as having a "cauliflower" cloud, but a reporter present also spoke of "the mushroom, now the common symbol of the atomic age." Mushrooms have traditionally been associated both with life and death, food and poison, making them a more powerful symbolic connection than, say, the "cauliflower" cloud. (Weart 1988) Year 1946 (MCMXLVI) was a common year starting on Tuesday (link will display full 1946 calendar) of the Gregorian calendar. ... A 23 kiloton dropped nuclear weapon, known as Operation Crossroads (Event Able) A 21 kiloton underwater nuclear weapons effects test, known as Operation Crossroads (Event Baker), conducted at Bikini Atoll (1946). ...

Physics

Inside a mushroom cloud: cooler air is drawn into the rising toroidal fireball, which itself cools into the familiar cloud appearance.

Mushroom cloud with prominent condensation ring from the Castle Romeo hydrogen bomb test.

Mushroom clouds are formed by many sorts of large explosions, though they are best known for their appearance after nuclear detonations. Nuclear weapons are usually detonated above the ground (not upon impact, lest most of the energy be dispelled into the ground) in order to maximize the effect of their spherical expanding fireball. After immediate detonation, the fireball itself begins to rise into the air, acting on the same principle as a hot-air balloon. Image File history File links Mushroom_cloud. ... Image File history File links Mushroom_cloud. ... A toroid is a doughnut-shaped object whose surface is a torus. ... Image File history File links Castle_romeo2. ... Image File history File links Castle_romeo2. ... Castle Romeo mushroom cloud. ... Hot air balloons are the oldest successful human flight technology, dating back to the Montgolfier brothers invention in Annonay, France in 1783. ...

A quite successful way to analyse the motion, once the hot gas has cleared the ground sufficiently, is as a 'spherical cap bubble' ^[1], as this gives quite good agreement between the rate of rise and observed diameter.

While it rises, air is drawn into it and upwards (similar to the updraft of a chimney), producing strong air currents known as "afterwinds", while inside the head of the cloud the hot gases rotate in a toroid shape. When the detonation itself is low enough, these afterwinds will draw in dirt and debris from the ground below to form the stem of the mushroom cloud. Look up Chimney in Wiktionary, the free dictionary. ... A toroid is a doughnut-shaped object whose surface is a torus. ...

Detonations produced high above the ground do not create mushroom clouds. The heads of the clouds themselves consist of highly-radioactive particles and other fission products, and usually are dispersed by the wind, though weather patterns (especially rain) can produce problematic nuclear fallout. ^[2] Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... Fission products are the residues of fission processes. ... Fallout is the residual radiation hazard from a nuclear explosion, so named because it falls out of the atmosphere into which it is spread during the explosion. ...

Detonations below ground level or deep below the water (for instance, nuclear depth charges) also do not produce mushroom clouds, as the explosion causes the vaporization of a huge amount of earth and water in these instances. Detonations underwater but near the surface can produce mushroom clouds, however, as well as large "Wilson cloud chamber effect" (such as that seen in the well-known pictures of the Crossroads Baker test). A 23 kiloton dropped nuclear weapon, known as Operation Crossroads (Event Able) A 21 kiloton underwater nuclear weapons effects test, known as Operation Crossroads (Event Baker), conducted at Bikini Atoll (1946). ...

Nuclear mushroom clouds are often also accompanied by short-lived vapor clouds or vapor rings. These are created by the blast wave causing a sudden drop in the surrounding air temperatures, causing water vapor in the air to condense around the explosion cloud.

Image File history File links Download high-resolution version (2540x185, 187 KB) Sequence showing mushroom cloud formation from a U.S. test at the Nevada Test Site. ...

References

Wikimedia Commons has media related to:

Mushroom cloud

1. ^ Batchelor (1967, Chapter 6.11, 'Large Gas Bubbles in Liquid')
2. ^ (Glasstone and Dolan 1977)

• Batchelor, G. K. An Introduction to Fluid Dynamics, Cambridge, UK: Cambridge University Press, 1967.
• Glasstone, Samuel, and Dolan, Philip J. The Effects of Nuclear Weapons, 3rd edn. Washington, DC: United States Department of Defense and Energy Research and Development Administration, 1977. (esp. "Chronological development of an air-burst" and "Description of Air and Surface Bursts" in Chapter II) (This entire book is available here: http://www.princeton.edu/~globsec/publications/effects/effects.shtml .)
• Vigh, Jonathan. Mechanisms by Which the Atmosphere Adjusts to an Extremely Large Explosive Event, 2001. (See: http://euler.atmos.colostate.edu/~vigh/other_works/at735/vigh_adjustment_mechanisms.pdf .)
• Weart, Spencer. Nuclear Fear: A History of Images. Cambridge, MA: Harvard University Press, 1988.

Image File history File links Commons-logo. ...

External links

• Carey Sublette's Nuclear Weapon Archive has many photographs of mushroom clouds
• DOE Nevada Site Office has many photographs of nuclear tests conducted at the Nevada Test Site and elsewhere