The Earth is the third planet from the Sun and the fifth-largest of the eight planets in the Solar System. It is in fact one of the four terrestrial planets in our galaxy, and the largest one at that. A terrestrial planet means one that is made out of rock and metals, as opposed to a gas giant, which is a planet composed primarily of objects that are not categorized as rock or other solid matter.
Out of the eight planets in our Solar System, Earth is the only planet that contains water and is currently capable of sustaining life. Looking at satellite images of the planet, Earth looks like a giant blue marble, which is why it is often referred to as the Blue Marble or the Blue Planet. Of course to most of us, Earth will always be ‘the world.’
Some facts and figures about Earth:
- Earth is 150 million km (93 million miles) or one AU away from the Sun.
- It is densest of all the other planets in the Solar System.
- It has one satellite, called the Moon.
- Earth has water and an atmosphere which facilitate the sustenance of life.
- Nearly 70 percent of Earth's surface is covered in water.
- The earth’s atmosphere consists of 78 percent nitrogen, 21 percent oxygen, and 1 percent other ingredients.
- The atmosphere affects Earth's long-term climate and short-term local weather; shields us from nearly all of the sun’s harmful radiation; and protects us from meteors.
- It takes the Earth 24 hours to complete a rotation, hence one day.
- It takes the Earth about 365.26 days to complete one revolution around the Sun.
- The four seasons are a result of Earth's axis of rotation being tilted more than 23 degrees.