EARTH

Earth is the third planet from the Sun and the only object in the Universe known to harbor life . According to radiometric dating and other sources of evidence, Earth formed over 4 billion years ago . [24] [25] [26] Earth's gravity interacts with other objects in space, especially the Sun and the Moon , Earth's only natural satellite . Earth revolves around the Sun in 365.26 days, a period known as an Earth year . During this time, Earth rotates about its axis about 366.26 times. [n 5] Earth's axis of rotation is tilted, producing seasonal variations on the planet's surface. [27] The gravitational interaction between the Earth and Moon causes ocean tides , stabilizes the Earth's orientation on its axis, and gradually slows its rotation. [28] Earth is the densest planet in the Solar System ...