In this session, we have investigated the structure and age of the Earth via the formation of the universe and the solar system.
The universe formed about 14 billion years ago, and gradually evolved into galaxies, solar systems, stars and planets. The planets in our solar system are either small and rocky (Mercury, Venus, Earth and Mars) or gas giants (Jupiter, Saturn, Uranus and Neptune). Between Mars and Jupiter is a belt of asteroids, some of which enter the Earth’s atmosphere as meteorites.
Using seismic waves produced by earthquakes, the different layers of the Earth (the crust, the mantle and the core) can be mapped.
Using the predictable rates at which some elements radioactively decay, the age of the Earth has been calculated as 4.6 Billion years.
NASA / public domain