Earth, our home planet, is a world unlike any other ... This axis of rotation is tilted 23.4 degrees away from the plane of Earth's orbit around the sun, giving us seasons. Whichever hemisphere ...

Elementary students can learn about creating positive change in the environment with these engaging Earth Day activities.

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.

The gorges span about 2,500 miles and cut up to 4.3 miles into the red planet’s surface. The network of chasms is four times deeper—and five times longer—than Earth’s Grand Canyon ...

Its orbit is about 1.5 times the size of Earth ... the Red Planet through an early telescope in the late 1700s. The first spacecraft to successfully reach Mars was NASA's Mariner 4 probe, in ...