Earth formed around 4.54 billion years ago. Knowing how old Earth is can be more difficult to confirm because Earth's age is not only based on the age of rocks, but also the isotopic estimates of what ...

Planetary scientists have long debated where the material that formed Earth comes from. Despite its location in the inner solar system, they consider it likely that 6–40% of this material must have ...

The inner solar system may have formed differently from how we have long thought it must have. For decades, researchers have thought that the rocky planets formed from a single disc of dust and debris ...