Uranium
Uranium-238 is the most stable isotope of uranium, with a half-life of about 4.468 years, roughly the age of the Earth. Uranium-235 has a half-life of about 7.13 years, and uranium-234 has a half-life of about 2.48 years.
For natural uranium, about 49% of its alpha rays are emitted by each of U atom, and also 49% by U (since the latter is formed from the former) and about 2.0% of them by the U. When the Earth was young, probably about one-fifth of its uranium was uranium-235, but the percentage of U was probably much lower than this.
Uranium – Twisting the Dragon's Tail
The use of uranium at the conclusion of World War II ushered in the atomic age. Uranium has since been utilized as a source of energy as well as in cancer treatment. Derek Muller visits Chernobyl and Fukushima, where nuclear disasters have occurred. The proposition that in our energy-hungry, warming world, uranium both tempts with unbelievable power and threatens all life on earth is explored.