but since our planet was formed around 4.6 billion years ago, the length of a day has been gradually growing. A day is the time period of a full rotation of the Earth with respect to the Sun.

In this collection of trivia bits, you'll find interesting facts on how the ... U.S. Geological Survey, the earth's geological age is estimated to be approximately 4.5 billion years old.

Earth formed over 4.5 billion years ago from a swirling cloud of gas and dust squished together by gravity. That same cloud gave rise to our entire solar system, including our star, the sun.

3. It is more about rebuilding connection than just switching off - Earth Hour is the moment when local and global communities unite and switch off to show they care about the future of our planet. 4.