Earth was formed around four and a half billion years ago. Within its first billion years, life appeared in its oceans and began to affect its atmosphere and surface, promoting the proliferation of aerobic as well as anaerobic organisms and causing the formation of the atmosphere's ozone layer. This layer and Earth's magnetic field block the most life-threatening parts of the Sun's radiation, so life was able to flourish on land as well as in water. Since then, Earth's position in the Solar System, its physical properties and its geological history have allowed life to persist.
The Earth is about 7,926 miles in diameter. The Earth is the fifth-largest planet in our Solar System (after Jupiter, Saturn, Uranus, and Neptune).
The Earth has one moon. The diameter of the moon is about one quarter of the diameter of the Earth.
Each day on Earth takes 23.93 hours (that is, it takes the Earth 23.93 hours to rotate around its axis once). Each year on Earth takes 365.26 Earth days (that is, it takes the Earth 365.26 days to orbit the Sun once).
The Earth's rotation is slowing down very slightly over time, about one second every 10 years.
The Earth is about 7,926 miles in diameter. The Earth is the fifth-largest planet in our Solar System (after Jupiter, Saturn, Uranus, and Neptune).
The Earth has one moon. The diameter of the moon is about one quarter of the diameter of the Earth.
Each day on Earth takes 23.93 hours (that is, it takes the Earth 23.93 hours to rotate around its axis once). Each year on Earth takes 365.26 Earth days (that is, it takes the Earth 365.26 days to orbit the Sun once).
The Earth's rotation is slowing down very slightly over time, about one second every 10 years.
First Photo of Earth From the Moon:
This photo reveals the first view of Earth from the moon, taken by Lunar Orbiter 1 on August 23, 1966. Shot from a distance of about 236,000 miles (380,000 kilometers), this image shows half of Earth, from Istanbul to Cape Town and areas east, shrouded in night. |
First Full-View Photo of Earth:
This famous "Blue Marble" shot represents the first photograph in which Earth is in full view. The picture was taken on December 7, 1972, as the Apollo 17 crew left Earth’s orbit for the moon. With the sun at their backs, the crew had a perfectly lit view of the blue planet. |