The activity concentration arising solely from the decay of the uranium isotopes (U-234, U-235 and U-238) found in natural uranium is 25.4 Bq per mg. In nature, uranium isotopes are typically found in ...

For example, about 1.5 percent of a quantity of Uranium 238 will decay to lead every 100 million years. By measuring the ratio of lead to uranium in a rock sample, its age can be determined.

Powering spacecraft with solar energy may not seem like a challenge, given how intense the Sun’s light can feel on Earth.

For example, about 1.5 percent of a quantity of Uranium 238 will decay to lead every 100 million years. By measuring the ratio of lead to uranium in a rock sample, its age can be determined.