Fission is a nuclear reaction in which the atomic nucleus, which is held together by the strongest force in the universe, the "Strong Nuclear Force", splits into fragments. The main material used in fission experiments is "uranium" because the uranium atom is one of the heaviest. In other words, there are plenty of protons and neutrons in its nucleus.
In fission experiments, scientists shot a neutron at the uranium nucleus at great velocity. They faced a very interesting situation. After the neutron was absorbed by the uranium's nucleus, the uranium nucleus had become very unstable. The nucleus' being "unstable" means the formation of a difference between the numbers of protons and neutrons in the nucleus, resulting in an imbalance in its structure. Therefore, the nucleus starts splitting into fragments while emitting a certain amount of energy to eliminate this imbalance. The nucleus, under the impact of the energy released, starts ejecting the components it contains at great velocity.

Considering the results these experiments yielded, neutrons were accelerated and uranium was bombarded with neutrons in special environments called "reactors". However, uranium is bombarded with neutrons according to a very fine measure, not randomly, because any neutron bombarding the uranium atom has to hit the uranium immediately and at the desired point. That is why these experiments are conducted taking every probability into consideration. The amount of the uranium to be used, the amount of the neutrons used to bombard the uranium, and the duration and speed at which the neutrons will bombard the uranium should all be very precisely calculated.

After all these calculations are made and the appropriate setting is prepared, the nucleus is bombarded with neutrons in such a way that they penetrate the nuclei of the atoms in the uranium. It is sufficient that the nucleus of at least one of the atoms in this mass is split in two. In this division, an average of two or three neutrons are sent out from the mass of the nucleus at great velocity and high energy. Neutrons that are released start a chain reaction by colliding with other uranium nuclei within the mass. Each newly split nucleus behaves like the initial uranium nucleus. Thus, a chain of nuclear reactions starts. A large number of uranium nuclei are split into fragments as a result of these chain reactions, causing an enormous amount of energy to be released.

It was these nuclei divisions that have caused the Hiroshima and Nagasaki disasters, causing the death of tens of thousands of people. At the moment of the detonation of the atomic bomb dropped on Hiroshima by the United States in 1945 during World War II, and in its aftermath, approximately 100,000 people died. Another atom bomb dropped on Nagasaki by America three days after the Hiroshima disaster caused the death of another 40,000 people right at the moment of detonation. While the power released by the nuclei caused the death of many people, it also destroyed a very large residential area, and gave rise to many irreparable genetic and physiological disorders in the remaining residents of that area, due to the radiation released, which was to affect generations to come.

If our earth, the whole atmosphere, everything animate and inanimate including us, are composed of atoms, what prevents atoms from being involved in nuclear reactions like the ones in Hiroshima and Nagasaki, that could occur anytime and anywhere?
The neutrons are created in such a way that, when they are free in nature - without being linked to a nucleus - they are subjected to a decomposition called "beta disintegration". Because of this disintegration, no neutrons wander freely in nature. Therefore, neutrons that are to be used in nuclear reactions must be obtained through artificial methods.

This makes clear that, Allah, the Creator of the entire universe, created everything with a precise measure. If neutrons had not decomposed in the free state, the earth would be nothing but an uninhabitable spherical celestial body where endless nuclear reactions took place. Allah created the atom along with this colossal power within it and keeps this power under control in a phenomenal way.