AY 101 Lecture Notes - Lecture 4: Scientific Notation, Kilogram, An Angle
Measurement Methods
Astronomers use a variety of methods to quantify the natural phenomena
that they measure. Because the physical factors that are measured in
astronomy are sometimes quite large or small, astronomers use scientific
notation, or exponential numbers, to express these measurements. A
number written in scientific notation is a number between 1 and 10 and
multiplied by a power of 10 (see Table 1).
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Document Summary
Astronomers use a variety of methods to quantify the natural phenomena that they measure. Because the physical factors that are measured in astronomy are sometimes quite large or small, astronomers use scientific notation, or exponential numbers, to express these measurements. A number written in scientific notation is a number between 1 and 10 and multiplied by a power of 10 (see table 1). Names for the most common other units are formed by the addition of the following prefixes to these terms: kilo (thousand), mega (million), giga (billion), centi (1/100), milli (1/1000), and micro (1/1,000,000). So, for example, a kilometer is a thousand meters, while a millimeter is one thousandth of a meter. Some astronomical measurements using the metric system are shown in table 2. Astronomers also utilize angles in measuring celestial objects, especially in quantifying their position and movement in the sky. An angle is formed by two lines that have the same endpoint.
