Our planet Earth, on which we live, is part of the solar system. In the center of the solar system, a hot star shines brightly - the Sun. Eight main planets revolve around it at different distances from the Sun. One of them, the third in a row, is our Earth.
Each planet has its own orbit in which it moves around the Sun. A complete revolution around the Sun is called a year. On Earth it lasts 365 days. On planets that are closer to the Sun, a year lasts less, and on those that are further away, a full revolution can take several Earth years. The planets also rotate around their axis. One such complete revolution is called a day. On Earth, a day (a revolution around its axis) is approximately 24 hours (more precisely 23 hours 56 minutes 4 seconds).
