Concrete is the most common artificial composite material of all and typically consists of loose stones (aggregate) held with a matrix of cement. Concrete is a very robust material, much more robust than cement, and will not compress or shatter even under quite a large compressive force.
2) Y-axis contains absolute brightness Why do astronomers use the H-R Diagram? Astronomers use H-R Diagrams to classify stars and to understand how stars change over time.
To figure out luminosity from absolute magnitude, one must calculate that a difference of five on the absolute magnitude scale is equivalent to a factor of 100 on the luminosity scale â for instance, a star with an absolute magnitude of 1 is 100 times as luminous as a star with an absolute magnitude of 6. Limitations of absolute magnitude. While the absolute magnitude scale is astronomers' best effort to compare the brightness of stars, there are a couple of main limitations that have to ...