The stars are very far away. We sometimes figure out how far away the stars are by looking at them from two different places and seeing how high up they are in the sky. We use what we know about three-sided things to learn how far away they are.

The most far-away we can figure out needs two different places to look from that are very far away from each other, or very good man-made eyes in space. On this world we can only use this plan for stars that would take two or three tens of years for their light to reach us (light years), or with very good man-made eyes in space a ten and a half hundred light years, seeing how high up the stars are in the sky when the man-made space-eyes are on different sides of the sun.

Some stars that have died will flash in space. How bright they are and how fast they flash is almost the same no matter where they are, so we can use this to figure out how far away they are, even if they are very, very, very far away. This lets us figure out how far away some of the most far away things in space are.