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You'll need an orange marker and a red one if you want to draw a binary star. Learn how to draw a binary star with help from an artist in this free video clip.
No one knows how many stars exist, but rough estimates by National Geographic are in the thousands of billions for the Earth's universe alone. While even on the clearest, darkest night, only about 3,000 stars are visible to the naked eye, stars continue to fascinate Earth's human inhabitants. Composed largely of gas and plasma, stars produce light, heat, ultraviolet rays, X-rays and other forms of radiation. Scientists use stars' color, size, brightness and age to classify them into groups.
The brightest star in the sky, Sirius is also commonly known as the Dog Star. Because of its visibility, it is the most well-known of stars, with many references found throughout history and in all cultures. Actually a binary star system (two stars), Sirius can be seen from almost all inhabited regions of Earth. The age of Sirius is estimated to be approximately 230 million years old, and it is expected to take about a billion years from its formation before using up all of the hydrogen at its core.
A binary star is a system that has a center containing two stars that are close enough so that their gravitational pulls force them to move in orbit around each other. These stars are not uncommon in the universe, and there are a number that are relatively close to our own solar system. These include Algol, Cygnus X-1 and the famous Sirius. Binary stars have a special importance in astronomy that allows them to act as a measuring point for the mass of all stars in the universe.
