Why do nuclear bombs form mushroom clouds? - Livescience.com

So, instead of an expanding ball of fire, why do nuclear explosions result in mushroom clouds?

Although the outburst of energy does initially form a sphere of hot air, that's only the beginning of the story, according to Katie Lundquist, a researcher of computational engineering at Lawrence Livermore National Laboratory in California.

"The way that a sphere is shaped, you have the largest column of the low-density fluid in the middle, so that rises the fastest," like the middle of a cupcake rising in the oven, Lundquist said.

Although the entire sphere rises, because this middle column elevates with greater urgency, the cooler air outside the sphere begins to "rush in below the bubble that's rising," Lundquist told Live Science?

There's "this jet of material that's being sucked into the vacuum that's pushing up, and so that forms the mushroom cloud on the top and the flatter area within the torus on the bottom," Lundquist said.

This jet, which sucks up dirt and debris, forms the stem of the mushroom even as it feeds into the mushroom cap.

There's "a very distinct white cloud, and then a brown below that," Lundquist said.

Among the tested nuclear bombs that were stronger and/or exploded closer to the ground, the stem and cap merged into the classic mushroom profile, Lundquist said.

Originally published on Live Science

Thank you for signing up to Live Science