StarChild Question of the Month for November 2001

Question:

How do we measure the distances to things in space?

Answer:

It is not an easy thing to measure the distances to objects in the universe since these objects are usually very far away. We can't just run out there with a ruler! To measure distances in the universe, we will need to construct what is commonly referred to as a "cosmic distance ladder". In other words, astronomers use different methods to determine the distances to objects; the specific method which is used depends on how far away the object is. But all of the methods are wonderful combinations of science and mathematics!

The links below will take you to descriptions of various common methods.

• Radar - measuring distances in our solar system
• Parallax - measuring distances to nearby stars
• Cepheids - measuring distances in our Galaxy and to nearby galaxies
• Supernovae - measuring distances to other galaxies
• Redshift and Hubble's Law - measuring distances to objects far, far away

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