Blissful

 

 

Co­smic rays enter the earth's atmosphere in large numbers every day. For example, every person is hit by about half a million cosmic rays every hour. It is not uncommon for a cosmic ray to collide with an atom in the atmosphere, creating a secondary cosmic ray in the form of an energetic neutron, and for these energetic neutrons to collide with nitrogen atoms. When the neutron collides, a nitrogen-14 (seven protons, seven neutrons) atom turns into a carbon-14 atom (six protons, eight neutrons) and a hydrogen atom (one proton, zero neutrons).

 

The energy source is a mass of radioactive material such as uranium or plutonium. This material is very unstable; every atom's nucleus is ready to fall apart ('decay') at the slightest nudge, releasing unneeded energy and extra neutrons. In the diagram, the plutonium (B) is given that nudge by the outer casing of TNT (A), which explodes all around it.

Here's what happens; the process is called 'Nuclear Fission':


The plutonium is unstable, or radioactive. Its atoms are constantly 'falling apart', breaking up into smaller elements that are more stable. Every time one nucleus does this, it releases the extra energy it no longer needs to hold it together, as well as a few left-over neutrons. This energy, and the escaping neutrons, is what we describe as the radiation being emitted from the radioactive plutonium. This energy and flow of escaping neutrons can damage human cells, so radioactivity is dangerous.
Enough atoms in the chunk of plutonium are breaking down at any one time to make the chunk of plutonium warm up, but not enough to be considered an explosion.

 

This is a much nastier bomb. Not only does it release much more energy, using a process called 'nuclear fusion', but it is triggered not by TNT, but by an atomic bomb!
The central core (B) is a mass made up of trillions of two kinds of atoms, which are both isotopes of hydrogen, called deuterium and tritium. (These are just hydrogen atoms with one or two extra neutrons in each nucleus). Small atomic bombs (A) scattered around the outside cause the deuterium and tritium to be squeezed into a very dense mass, which initiates a process called nuclear fusion, releasing great quantities of energy.
This process is difficult to achieve; it's been described as trying to squeeze an unopened can of Coke into a little ball without spilling any Coke!
But there's more! As the core explodes, it causes the bomb casing, (C), which is made from uranium, to undergo fission, creating even more energy. In other words, an atomic bomb sets off a fusion bomb, which also triggers another atomic bomb!

Here are the details of the fusion process:


The block of deuterium and tritium atoms are squeezed into a super-dense mass by the exploding atomic triggers. Nuclei of these two isotopes are squeezed together by the force of the explosion.