The Sun is the key to life on Earth, and yet it’s incredibly far away. How far away is the Sun? On average, the Sun is approximately 150 million kilometers or 93 million miles away from the Earth.
This number is an average, though, because the Earth follows an elliptical path around the Sun. Sometimes it’s closer and other times it’s more distant from the Sun. At the closest point of the Earth’s orbit, called perihelion, the Sun is 147 million km away from Earth. And then at the most distant point of the Earth’s orbit, known as aphelion, the Sun is 152 million km away from Earth.
Astronomers actually use the average distance from the Sun to the Earth as a standard measuring tool for calculating distances in the Solar System. 1 astronomical unit, or AU, is the average distance from the Earth to the Sun; approximately 150 million km. So, Mars is 1.5 AU from the Sun, and Pluto is 39.5 AU from the Sun.
We’ve also recorded several episodes of Astronomy Cast about the Sun. Listen here, Episode 30: The Sun, Spots and All.