When the bomb explodes, the energy shoots indiscriminately in all directions. So why would a nuclear explosion lead to a mushroom cloud instead of an ever-expanding fireball?
The Baker Day explosion at Bikini Atoll in the Marshall Islands was recorded by an automated camera on a nearby island. Notice the mushroom cloud that forms immediately after the explosion
<h1 class="pgc-h-arrow-right" data-track="34" > the cause of mushroom clouds</h1>
Katie Lundquist, a computational engineering researcher at Lawrence Livermore National Laboratory in California, said: "Although the energy burst did initially form a hot air sphere, this is just the beginning of the story. As hot air rises, the core of the larger sphere in the middle column is subjected to greater buoyancy than the edge."
"In the shape of the sphere, there is the largest column of low-density fluid in the middle, so it rises the fastest," like the middle of a cupcake that rises in an oven.
Although the entire sphere was rising, as this intermediate column rose with greater urgency, the colder air outside the sphere began to "rush underneath the rising bubbles."
This causes the rising bubbles to twist into a doughnut or donut shape. And because the hot air molecules move rapidly in a charged state, bouncing each other at high speeds, they eventually form such a large space between them that they form a state of near-vacuum. This jet of material is sucked into a vacuum and pushed upwards, creating a mushroom cloud at the top and a flatter area within the bottom torus. This jet of inhalation of dust and debris forms the stem of the mushroom, even as it enters the mushroom cap.
The figure shows the direction in which the fluid moves after a nuclear explosion.
Wartime dropped nuclear bombs and scientific experiments have shown that mushroom clouds can form on Earth,
<h1 class="pgc-h-arrow-right" data-track="41" > would a mushroom cloud be formed when a nuclear bomb explodes in space? </h1>
If the Moon is bombed, will a mushroom cloud be produced? Say the answer is no.
"You need an atmosphere so they can have that fluid substance," like air, "and that doesn't happen in a vacuum." The Moon's airless environment could not twist the initial sphere into a torus, and there would be no difference in air density to absorb that material column to grow clouds.
<h1 class="pgc-h-arrow-right" Data-track="43" > mushroom clouds from various bomb explosions? </h1>
Just as there are different kinds of mushrooms, there are also various mushroom clouds. Depending on the bomb's explosion yield and explosion altitude, the resulting mushroom cloud will have different characteristics.
The explosion that occurred in Japan at the end of World War II had two main parts. Part of it includes billowing white clouds above, made of vaporization products from the bomb itself and condensate in the surrounding air. The other part is a stem of brown material and fragments that extend from the ground. But the two are not fully in contact, as shown in the figure below.
A nuclear bomb attack on Nagasaki, Japan, on August 8, 1945
"There was a very pronounced white cloud, and then a brown cloud below." The caps and rods on these clouds did not meet because the bomb detonated at a high altitude, nearly 610 meters above the ground. Despite the devastating damage they wreaked, they were rather weak compared to weapons made later, with an explosive force of about 20 kilotons of TNT or less when they exploded. (The Soviet Union, on the other hand, produced 50,000 kilotons of TNT.) ）
Among the tested nuclear bombs, which were more powerful or exploded closer to the ground, the stem and cap fused into the classic mushroom shape.
Lundquist and her lab colleagues study these effects so that in the event of a nuclear crisis, they will be able to "know the location of radioactive particles to correctly predict settlement and then provide guidance on the management of consequences that protect public health." ”
While the threat is real, the world's nuclear arsenal together contain nearly 10,000 nuclear bombs, down from more than 60,000 in the 1980s.