Facts About Stars I
Space and Astrology 6/18/11
By: Yona Williams
When you sing 'twinkle, twinkle, little star,' it is the glowing ball of gas that you are paying homage to. Interestingly, we donÃ¢â‚¬â„¢t think that the sun in the sky is a medium-sized star, but it is. In this article, you will learn facts and trivia about stars, including the average lifespan of a star.
Explain a Twinkling Star
What we call the twinkling of stars is referred to as stellar scintillation (or astronomical scintillation). The reason why stars look like they are twinkling or sparkling in the sky is because we are looking at them from Earth and thick layers of turbulent (moving) air in the Earth's atmosphere affects our view.
With the exception of the Sun, stars appear as tiny dots in the sky. However, when their light travels through the numerous layers of the Earth's atmosphere, the light of the star becomes bent (or refracted). This happens many times with the light being displayed in random directions. This process takes place every time the light hits an alteration in density, such as coming in contact with a pocket of cold air. The unpredictable refraction causes the star to look like it is moving slightly. To us, we perceive this movement as a 'twinkle.'
The effect of twinkling stars is something that happens when we are on Earth. If you were in outer space and looked at stars from a planet or other celestial object that didnÃ¢â‚¬â„¢t have an atmosphere, you would not see the stars as twinkling.
The Age of Stars
Have you ever wondered just how long a star lives for? A star is born when a large cloud of hydrogen gas collapses and produces enough heat that can burn nuclear fuel. The process creates a great deal of heat and radiation. As the nuclear fuel runs out (which takes about 5 billion years), the star grows larger and the core contracts. As a result, the star turns into a giant star that eventually explodes.
Depending on its initial mass, the star transforms into a dim, cool object, such as a black dwarf, neutron star, or black hole. Stars can live for billions of years, and interestingly, the larger stars have the shortest life span. The larger the stars, the hotter and faster they burn as opposed to their smaller cousins.
When someone studies the composition of stars, they focus on visible light (or the spectrum) of a star, which involves spectroscopy Ã¢â‚¬â€œ the study of the interaction between matter and radiated energy.
The total brightness of a star or galaxy is measured by its luminosity.
The universe is filled with stars Ã¢â‚¬â€œ most of which occur in groups consisting of at least two stars. When two stars are locked in elliptical orbit around their center of mass, they are referred to as a binary star system. About 50% of all stars belong to a binary star system.