Tony Isaac, March 2, 2006

One of the issues that dogs creationists is this: If the Universe were created only thousands of years ago, how is it that we can see stars that are millions of light years away?

Triangulation

Measuring the distance to stars within a few hundred light years can be done through triangulation.  Careful measurements are made to determine the position of a star, six months apart.  By using the diameter of the earth's orbit as the base of an imaginary triangle, and the star's position as the third corner of the triangle, the precise angles measured can be used to determine the distance to the star.

This method is limited because of the extreme distances in space.  To measure the distance to the nearest star, imagine the earth's orbit as being one foot in diameter.  At that scale, Alpha Centuri would be 27 miles away!  At distances greater than about 200 light years, triangulation becomes useless.

Distant Stars

According to WikiPedia, greater distances are measured using the relationship of brightness and size of "variable" stars--stars that change in brightness.  Unfortunately, this technique is inexact at best.  What other factors besides distance might affect the brightness of stars?  We cannot know what particles or gasses might lie between us and the distant stars being measured.

As far as we can tell, no one will ever be able to verify whether the measurements now being taken are correct.  Astronomers are free to continue assigning distance estimates to stars, knowing that no one will ever be able to really prove them right or wrong.

Could all the stars we see fit within a space of a few thousand light-years, or billions?  That is a question that has not yet been answered.

Copyright © 2006 by Tony Isaac