What is a star?
Stars have intrigued mankind since the beginning of time. Poems, religious stories and children's nursery rhymes feature stars. No one can admit to not being moved when standing outside on a dark night and seeing thousands of stars!
A star is a huge mass of plasma, or matter, that is held together by its own gravity. The matter consists mostly of hydrogen and helium, the most commonly found elements in the Universe. Hydrogen and helium clouds float around in space in clouds of cold gas. Every now and then a cosmic event like a galaxy collision, a supernova explosion or other disturbance will take place that causes the cloud to collapse and heat up. This forms the base of a new star.
This heating process is nothing like your normal oven. It takes millions of years and reaches massive temperatures of over 18 million degrees Fahrenheit combined with mega internal pressures. At these temperatures, hydrogen changes to helium in a nuclear fusion reaction and a star is born. Stars can be created alone, in pairs, clusters or even in entire galaxies.
The closest and most familiar star to us is the Sun. Other stars are much further away and simply appear as pin points in the sky. Stars go through various phases during their lifetimes. Depending on the temperatures at which they burn, they appear to have different colors, hence the names red, brown, orange or yellow dwarfs. When the hydrogen runs out and stars cannot burn any longer, they will change into other cosmic bodies. Smaller stars will become white dwarfs and larger stars will explode to become supernova or those illusive, mysterious black holes!