Astronomy Today

Measuring Units

How do astronomers measure sizes and distances in the universe?

Since tape measures are pretty inconvenient measuring tools in astronomy, other methods are used. Geometric methods like parallax and standard candles, such as Cepheid variables, are the most common ways to make such measurements. Along with the standard terrestrial units of length, like meters or miles, specialized units have been developed to make cosmic measurements. These include astronomical units (AU), light-years, and parsecs.


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