well well well... noding some APOD content today, and what do I stumble upon but a little astronomy nodeshell...
Certain stars have a
variable pulsing intensity. The
period of a
cycle through this
luminosity is directly
linked to the star's
intrinsic brightness. A
ratio between this
calculated brightness, and its brightness when
observed from
earth allows an
approximation of its
distance.
Some nearby
galaxies (like
M31), actually have observable Cepheids on their outer
edges. The calculated distances
really
fucked up all of
science's
perception of the size of the
universe. The result was the
Cosmological Shapley-Curtis debate,
<---- (feel free to node it, otherwise I will some day..) and even
extensions on
Einstein's
theories!
Suddenly a member of The Nodeshell Rescue Team...