One of the most difficult problems in astronomy is measuring the
vast interstellar distances
between us and everything
. Over the centuries, astronomers have developed a
series of methods, each applicable to more distant
objects, and each dependent on the previous methods. The series of
methods is known collectively as the "cosmic distance scale ladder".
Here are some of the most important rungs
on the CDS ladder:
- The distance to the Moon
- The distance to the Sun
- Parallax distances to nearby
- The Cepheid Distance Scale
- Hubble's Law: the redshift-distance relation.
There are other important distance methods involving eclipsing binaries,
Type Ia supernovae (and other standard candles), moving star clusters, and other beasts.