Star Light, Star Bright...What Are Stars?

Hydrogen and gravity components are used when stars are born. Nebula, dust, gas clouds are "nursery of stars with millions of stars" (poles). These "great cosmic dust and hydrogen clouds" (Science Online) are attracted to each other by gravity, collapse inward and form a dense central plexus. As this process continues, heat is released and trapped inside the center of the mass and the temperature rises. This previous star continues to be crushed inside, increases the density of its nucleus, causing a sudden temperature rise.

The apparent brightness of a star is represented by its apparent size. It depends on the brightness of stars, the distance from the earth, the annihilation of dust and gas between the stars, and the change in light as the stars pass through the atmosphere of the earth. The intrinsic or absolute size is directly related to the brightness of the star, and if the distance between the earth and the star is 10 seconds (32.6 light years) it is the apparent size of the star. The apparent and absolute amplitude scales are all log units and the integer difference in amplitude is equal to about 2.5 times the change in brightness (the fifth root of 100 or about 2.512). This means that the first star (+1.00) is about 2.5 times the second star (+ 2.00), about 100 times brighter than the 6th star (+6.00). The darkest star visible to the naked eye under good visual conditions is around +6.

The energy produced by stars is produced by nuclear fusion of the stars' nuclei. Brightness is measured in the order of magnitude, the brighter the star value, the lower the amplitude. There are two ways to measure the brightness of a star, the apparent size is the brightness seen from the earth, and the absolute size is the brightness of the star seen from the standard distance of 10 seconds (32.6 light years). Hertzsprung Russell Diagram can be used to draw a star on a star map (see picture below).

In the 1920 's, Edwin Hubble observed stars with different brightness in the light called Andromeda Nebula. He knows that the brightness of these stars will change with their true brightness. Then he saw how bright they looked to find the distance to Andromeda Nebula. Many astronomers thought that the Andromeda Nebula was a solar system within the boundary of the Milky Way at that time. Mr. Hubble shows that this light is actually an independent galaxy - the Andromeda galaxy we know today - the largest spiral galaxy outside our Milky Way