How do we know the distances to the stars? No, we don’t use a very, very long tape measure. We have to be a little more clever. There are
a number of different ways that one could find the distance to a particular star. Because of our orbital motion, we see an effect called parallax
as illustrated here. The annual shift of a star due to our orbital motion gives us a chance to use some relatively simple trigonometry to get a
distance. The better the measurement of the shift, the better the distance estimate. We know the distances to nearby stars fairly well with is
method.
Once we became familiar with the stars in our immediate neighborhood. we could then use the concept of the distance modulus to reach
even farther. Here is a handy, online distance calculator.
Looking for a particular star? Find it here!
