Units of Measurement
Astronomical Unit (AU):
An astronomical unit is Earth's average distance from the sun, about 150 million kilometers or about 93 million miles. For example, Jupiter is 5.2 AU from the sun. This means that Saturn is 5.2 times the distance Earth is from the sun. The AU is used when the number of miles is too small and the number of light years is too large. One AU is equal to 500 light seconds.
An astronomical unit is Earth's average distance from the sun, about 150 million kilometers or about 93 million miles. For example, Jupiter is 5.2 AU from the sun. This means that Saturn is 5.2 times the distance Earth is from the sun. The AU is used when the number of miles is too small and the number of light years is too large. One AU is equal to 500 light seconds.
Light year (ly):
A light year is the distance that light travels in one year, about 9.5 trillion kilometers. Light years are used since the distance between stars are so large that kilometers are not practical. A light year uses a unit of time to measure distance since light travels fast enough, 300,000 kilometers per second. This makes the distance of light traveled in a year a practical unit of measurement.
A light year is the distance that light travels in one year, about 9.5 trillion kilometers. Light years are used since the distance between stars are so large that kilometers are not practical. A light year uses a unit of time to measure distance since light travels fast enough, 300,000 kilometers per second. This makes the distance of light traveled in a year a practical unit of measurement.