Compact Bone. The next layer is made up of compact bone. It is a smooth but hard quality, with minimal gaps and spaces. This layer gives bones their white and solid appearance, and it is the part that you see when you look at a skeleton.
He used the inverse square law of light brightness on a particular type of variable star in those old star clusters. Some stars are very useful for finding distances to clusters and to other galaxies because they have a known luminosity that is large, so they can be seen from great distances away.ll of the RR Lyrae stars in a cluster have the same average apparent magnitude. In different clusters, the average apparent magnitude was different. This is because all RR Lyrae have about the same average absolute magnitude (=+0.6, or 49 solar luminosities).
What was the implication of the observation by Edwin Hubble that the Cepheid variable stars that he measured in the Andromeda Nebula appeared to be very faint compared with what was expected? The Andromeda Nebula was very far away, and was in fact a galaxy not a nebula.