Yes. In the ores of the earth.
in earth
Uranium is found in the earth only in the form of compounds. Uranium is present in cca. 200 minerals.
Helium is found in the sun. It is also found in the Earth's atmosphere.
It is known that uranium 238 is found in meteorites and Plutonium 242 is found in very small amounts naturally in Uranium ores here on earth. So I would take a guess that in meteorites where uranium is found, tiny amounts of plutonium 242 will also be found.
uranium, rare earth elements, and... YO MAMA!
5,2.10-6 mg U
Almost every element from hydrogen to uranium (going from smallest to biggest) is found naturally on Earth. Technitium is not found naturally on Earth, it is the exception. The trans-uranic elements are also not found naturally on Earth.
Uranium concentration in the earth crust: ca. 2,5 ppm (mg/kg) Uranium concentration in the sea water: ca. 3 ppb (micograms/kg)
This process is called stellar nucleosynthesis.
Geothermal heat energy from inside the earth is caused by the radioactive decay of Uranium in the mantle.
Yes; helium appear from radioactive disintegration of uranium or thorium.
Actinium exist in minute traces associated with uranium or thorium ores.