Emily Johnson
Mushroom clouds are the result of a large explosion, most commonly associated with nuclear detonations. However, they can be caused by any sufficiently powerful explosion or natural phenomenon, such as volcanic eruptions. The iconic cloud shape is formed when a large volume of lower-density gases is suddenly produced, rising rapidly due to buoyancy and forming a temporary vortex ring that draws up a central column of smoke, debris, and condensed water vapour. The upward flow of air after the explosion, combined with the reflection of heat and energy off the ground, creates the distinctive mushroom cap. The size and shape of the mushroom cloud are influenced by factors such as the explosive yield, height of detonation, and atmospheric conditions.
| Characteristics | Values |
|---|---|
| Cause | Any massive release of heat, including a nuclear explosion, volcanic eruption, forest fire, impact event, or a powerful explosion |
| Appearance | A distinctive mushroom-shaped cloud of smoke, debris, condensed water vapour, and solid particles |
| Colour | Initially red or reddish-brown due to the presence of nitrous acid and oxides of nitrogen; changes to white due to water droplets |
| Height | Depends on the heat energy of the explosion and atmospheric conditions; may reach the tropopause (6-8 miles above the Earth's surface) |
| Duration | May persist in the atmosphere for about an hour until dispersed by winds |
| Fallout | May appear as dry, ash-like flakes or invisible particles; can cause beta burns on exposed skin |
| Speed | The cloud attains its maximum height in about 10 minutes |
| Formation | A sudden, rapid, and concentrated release of heat creates a bubble of hot gas that rises and expands, forming a vortex and drawing up a central column of smoke and debris |
| Stability | The cloud is stabilized when it reaches its maximum height but continues to grow laterally |
Explore related products
What You'll Learn
Nuclear explosions
Mushroom clouds are most commonly associated with nuclear explosions. However, any sufficiently energetic detonation or deflagration will produce a similar effect. Mushroom clouds can be caused by powerful conventional weapons, including thermobaric weapons, and some volcanic eruptions and impact events can produce natural mushroom clouds.
A mushroom cloud is a distinctive mushroom-shaped flammagenitus cloud of debris, smoke, condensed water vapour, and solid particles of weapon debris resulting from a large explosion. The cloud may continue to be visible for about an hour or more before being dispersed by the wind into the surrounding atmosphere, where it merges with natural clouds in the sky.
The initial colour of some radioactive clouds can be red or reddish-brown due to the presence of nitrogen dioxide and nitric acid, formed from initially ionized nitrogen, oxygen, and atmospheric moisture. As the fireball cools and condensation occurs, the colour changes to white, mainly due to the water droplets, similar to an ordinary cloud.
The height reached by the radioactive cloud depends on the heat energy of the weapon and the atmospheric conditions. If the cloud reaches the tropopause, about 6-8 miles above the Earth's surface, it tends to spread out. If there is sufficient energy remaining, a portion of the cloud will ascend into the more stable air of the stratosphere. The cloud attains its maximum height after about 10 minutes and is then said to be "stabilized".
At the moment of a nuclear explosion, a fireball is formed. The ascent of this roughly spherical mass of hot, incandescent gases changes shape due to atmospheric friction, and the surface of the fireball is cooled by energy radiation, turning from a sphere to a violently rotating spheroidal vortex. A Rayleigh-Taylor instability is formed as the cool air underneath initially pushes the bottom fireball gases into an inverted cup shape. This causes turbulence and a vortex that sucks more air into the centre, creating external afterwinds and further cooling the fireball.
Mushroom Magic: Manure-Grown Funghi
You may want to see also
Conventional weapons
Mushroom clouds are clouds of smoke and debris that form and move through the air following an explosion. They are most commonly associated with nuclear explosions, but any sufficiently energetic detonation or deflagration will produce a similar effect.
The effect is not unique to nuclear explosions, and smaller explosions can also create mushroom clouds. For example, the 1917 Halifax Explosion produced a mushroom cloud, as did the Beirut explosion. Even a few kilograms of TNT can be enough to create a small mushroom cloud.
The formation of a mushroom cloud is the result of the interaction of gases of different densities. When a bomb explodes, a roughly spherical mass of hot, incandescent gases forms and changes shape due to atmospheric friction. The surface of the fireball is cooled by energy radiation, and the bottom of the sphere is pushed into an inverted cup shape by the cool air underneath. This causes turbulence and a vortex that sucks more air into the centre, creating external afterwinds and further cooling the fireball. The vapours condense to form a cloud containing solid particles of weapon debris and small drops of water from the air sucked into the rising fireball.
The height reached by the cloud depends on the heat energy of the weapon and the atmospheric conditions. If the cloud reaches the tropopause, about 6-8 miles above the Earth's surface, it will spread out. If there is sufficient energy remaining, a portion of the cloud will ascend into the stratosphere. The cloud will attain its maximum height after about 10 minutes and is then said to be "stabilized". It will continue to grow laterally, producing the characteristic mushroom shape.
Mushroom clouds can also be produced by powerful conventional weapons, including thermobaric weapons such as the ATBIP and GBU-43/B MOAB. Natural mushroom clouds can also occur as a result of volcanic eruptions and impact events.
Mushroom Hunting: A Forager's Guide to Finding None
You may want to see also
Volcanic eruptions
Mushroom clouds are often associated with nuclear explosions, but they can also occur as a result of natural events, such as volcanic eruptions.
Volcanoes can create mushroom-shaped clouds that resemble those produced by nuclear explosions. These clouds are formed when hot debris, gases, ash, rock, and steam are ejected during an eruption and shoot up into the sky. The specific shape of the mushroom cloud is determined by the volcano's internal composition and the nature of its eruption. Some mushroom clouds produced by volcanoes are tall and skinny, while others are short and wide.
The 1980 eruption of Mount St. Helens generated a prominent mushroom cloud that was visible for miles. This cloud was composed of ash, rock, and steam. The 1917 Halifax Explosion also produced a mushroom cloud, as did the 2020 Beirut explosion.
Mushroom clouds are characterised by a distinctive mushroom-like shape, typically consisting of a central column or "stem" and a rounded cap. They are formed by the rapid release of a large amount of heat, which creates a fireball that rises swiftly, pulling in cooler air from below. As the fireball ascends, it cools and slows down, changing shape due to atmospheric friction. The air surrounding the fireball continues to move upward, causing the cloud to spread out at the top and form the characteristic mushroom shape.
The height reached by the cloud depends on the heat energy released and the atmospheric conditions. If the cloud ascends to the tropopause, approximately 6-8 miles above the Earth's surface, it may spread out laterally. However, if sufficient energy remains, a portion of the cloud can enter the more stable air of the stratosphere, causing it to grow taller. The cloud typically reaches its maximum height within 10 minutes and is then considered stabilized. It can remain visible for about an hour or more before being dispersed by winds and merging with natural clouds.
Mushrooms: Carb Content and Nutritional Facts
You may want to see also
Explore related products
Rayleigh-Taylor instability
A mushroom cloud is caused by a large explosion, often associated with a nuclear detonation, but any sufficiently energetic explosion or natural event can produce a similar effect. Mushroom clouds are the result of the sudden formation of a large volume of lower-density gases at any altitude, which causes a Rayleigh-Taylor instability.
The Rayleigh-Taylor instability is a phenomenon that occurs when a parcel of heavier fluid is displaced downward, and an equal volume of lighter fluid is displaced upwards, resulting in a decrease in the potential energy of the system. This instability leads to the development of \"plumes\" and the tangling and rolling of spikes and bubbles into vortices. The initial perturbations progress from a linear growth phase to a non-linear growth phase.
The instability was first studied by Lord Rayleigh, who examined the behaviour of fluids in this context. G. I. Taylor made the important observation that this phenomenon is equivalent to when less dense fluid accelerates into denser fluid. This occurs during a nuclear explosion, as well as in other contexts such as deep underwater on the surface of an expanding bubble.
The Rayleigh-Taylor instability provides a good starting point for the mathematical study of stability due to its simple base state. The velocity and pressure fields in the equilibrium state can be described mathematically, and the evolution of the Rayleigh-Taylor instability follows four main stages. In the first stage, the perturbation amplitudes are small compared to their wavelengths, and the equations of motion can be linearized, resulting in exponential instability growth.
The Rayleigh-Taylor instability is distinct from the Plateau-Rayleigh instability (also known as Rayleigh instability) of a liquid jet, which occurs due to surface tension.
Teemo's Mushrooms: Stacking Damage Strategy
You may want to see also
Radioactivity
Mushroom clouds are the result of a massive release of heat, often from a nuclear explosion. However, they can also be caused by non-nuclear events such as volcanic eruptions, forest fires, impact events, or powerful conventional weapons. The formation of a mushroom cloud is characterised by a distinctive mushroom-shaped flammagenitus cloud of debris, smoke, and usually condensed water vapour.
The radioactivity of the mushroom cloud depends on the type of explosion and the atmospheric conditions. If the cloud reaches the tropopause, about 6-8 miles above the Earth's surface, it tends to spread out. However, if there is sufficient energy remaining, a portion of the radioactive cloud can enter the stratosphere. The height reached by the cloud is determined by the heat energy of the explosion and the atmospheric conditions.
The radioactivity of the mushroom cloud is concentrated in different parts of the cloud depending on the yield of the explosion. Lower-yield explosions have about 90% of their radioactivity in the mushroom head and 10% in the stem. In contrast, megaton-range explosions have most of their radioactivity in the lower third of the cloud. The radioactivity can cause beta burns, which present as discoloured spots and lesions on the backs of exposed animals.
The initial colour of the cloud can be reddish-brown due to the presence of nitrogen dioxide and nitric acid, formed from ionized nitrogen, oxygen, and atmospheric moisture. As the fireball cools, the colour changes to white due to the formation of water droplets. The ozone produced by the blast gives it a characteristic smell. The distribution of radiation in the mushroom cloud also varies with the type of weapon and the fusion-fission ratio.
Mushrooms: Are They Legal or Not?
You may want to see also
Frequently asked questions
A mushroom cloud is a cloud of debris, smoke, condensed water vapour, and solid particles that forms a distinctive mushroom shape in the sky.
Mushroom clouds are caused by a massive release of heat, usually from a nuclear explosion. However, any sufficiently energetic detonation or deflagration can create a mushroom cloud, including powerful conventional weapons, volcanic eruptions, forest fires, and impact events.
The initial colour of a mushroom cloud can be red or reddish-brown due to the presence of nitrogen dioxide and nitric acid. As the fireball cools, the colour changes to white due to the formation of water droplets. The cloud continues to rise and flatten, forming the rounded cap of the mushroom.
Depending on weather conditions, a mushroom cloud can persist in the atmosphere for about an hour until winds and air currents disperse it.
The tallest mushroom cloud ever recorded was from the detonation of the Tsar Bomba, a Russian nuclear weapon tested on 30 October 1961. It had a yield of 57 megatons, making it the most powerful nuclear explosion in history.
