When the earth formed naturally occurring radioactive materials?

When the Earth formed around 4.5 billion years ago, naturally occurring radioactive materials, such as uranium, thorium, and potassium-40, were present due to their formation in earlier generations of stars. These elements were incorporated into the planet's crust and mantle during the accretion process. Over time, their radioactive decay has contributed to the Earth's internal heat and has played a significant role in geological processes, including plate tectonics and volcanic activity. Additionally, these isotopes are used in radiometric dating, helping scientists understand the Earth's history.