Our Solar System - Earth
Earth is the third planet from the Sun and is the largest of the terrestrial planets in the Solar System, in both diameter and mass. Home to millions of species including humans, Earth is the only place in the universe
where life is known to exist. Scientific evidence indicates that the planet formed 4.54 billion years ago, and life appeared on its surface within a billion years. Earth's outer surface is divided into several rigid segments, or plates, that gradually migrate across the surface over periods of many millions of years. About 71% of the surface is covered with salt-water oceans, the remainder consisting of continents and islands. Earth interacts with other objects in outer space, including the Sun and the Moon. At present, Earth orbits the Sun once every 366.26 times it rotates around its axis. This length of time is a year, which is equal to 365.26 days.
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