When it comes to the measurement of distance, weight and brightness of a celestial body, the figures involved are absolutely exponential involving multiple zeros. This includes the time spans involving the study of our heavenly bodies. Although the exponential notations can help us in counting the voluminous unit of measurements involved, it is still easier if there is a specific unit of measurement that is intended for astronomy. Such is the term **“astronomical unit”** which is placed after the numerical value. *One (1) astronomical unit* is equivalent to *92,955,807 miles* or *149,957,870.7 kilometers*.

However, there is also another unit of measurement in terms of length that is greater than the astronomical unit; it is the more popular term, ‘light year’. One light year is equivalent to sixty thousand astronomical units. It is important to know how to use these two measurements. The astronomical unit is based from the actual distance of the earth and the sun, thus, this unit of measurement is often used to measure the distances between planets in a solar system. The light year is based from the distance to which a light travels in one year and is commonly used to measure the distances between stars and galaxies.