Here are some fun facts about Earth as we celebrate this planet we live on for Earth Day ... the inner core, the outer core, the mantle and the crust. The temperature of Earth’s inner core ...

The first layer is the crust, a thin outer shell that extends about 18 miles (30 km) below the planet's surface. The next layer, the mantle, stretches about 1,800 miles (2,900km) below Earth's ...

That’s because these planets are primarily made from gas and have no solid surface. This group of planets is also known as the ‘Jovian Planets’ after the Roman god Jupiter. Jupiter is ...