astronomical unit (km)

A Astronomical Unit (au) is the mean distance from the center of the Earth to the center of the sun.  This distance is 149,597,870 km which is one astronomical unit.

One Astronomical Unit is equal to:

• 149,597,870,691.0 meters
• 149,597,870.691 kilometers
• 92,955,807.267 miles
• 499.015 light seconds
• 8.3169 light minutes
• 0.1386 light hours
• 0.00001581 light years

Astronomical Units are often used in astronomy calculations featured in vCalc's Astronomy Calculator.

The Math / Science

Question: How far does the Earth travel around the Sun?
Answer: The Earth tracks 939,951,143 km in each orbit around the Sun
Here’s How: The Earth is in nearly a circular orbit around the Sun. So we can use the formula for the circumference of a circle to estimate the distance the Earth travels around the Sun based on the radius of the circle, which is the distance from the center of the Sun to the center of the Earth. That distance is 149,597,870 km which is one astronomical unit.

So, using basic geometry:

• C = 2⋅π⋅r 
• C = 2⋅π⋅149,597,870 km
• C = 939,951,143 km

Related Astronomical Units:

• Light Second
• Light Minute
• Astronomical Unit (au)
• Light Hour
• Light Day
• Light Year
• parsecs
• kilo-light years
• mega-parsec