Sunday, March 25, 2007
Few things you never knew about sun
We all think of the sun as being yellow or orange in color, but in reality, it is white. The yellow tones we see are actually due to a phenomenon known as "atmospheric scattering."
The sun is the brightest star in our galaxy right? Wrong. While most stars in the Milky Way galaxy are considered "red dwarfs" (relatively smaller and cooler stars), approximately 15% of the stars in the galaxy are brighter than our sun
We may picture that all the planets in our galaxy orbit around the sun, while the sun is essentially still. Actually the sun orbits the galactic center of the Milky Way galaxy, completing a revolution every 225 to 250 million years.
The sun is basically a giant nuclear fusion reactor. Its energy is derived from the nuclear fusion of hydrogen nuclei into the gas helium.
Scientists have just learned that the sun's magnetic field is vastly more active than previously thought. The Japanese satellite Hinode, launched in September 2006, began sending images back to earth in March 2007 showing dynamic gas movement through the sun's outer layers. Astronomers have hailed the discoveries, predicting an entirely new area of study will form based on the new data.
Many characteristics of the sun still puzzle modern scientists, such as the question: why is the sun's outer atmosphere measured at 1 million degrees K, while the surface is a relatively cool 6,000 K?
The ultraviolet light in the sun's rays is antiseptic, meaning it can kill microorganisms that cause infections.
Stonehenge, constructed roughly 3,000 years BC in what is now Great Britain, was likely an early scientific observatory built to measure the sun's movement across the sky (in reality, the Earth's movement) so they could predict astronomical phenomena.
We owe the structure of the 24-hour day to ancient Egypt's stories of their sun-god Ra, who was believed to spend the night hours traveling between the 12 domains of the dark underworld, and the light hours between the 12 domains of the day.
Scientists believe the sun will eventually die by turning into a "red giant." Sometime before that, the sun's mass will diminish as the outer layers expand, pushing the Earth and other planets further away from it but not before our water is boiled away and atmosphere obliterated. (But cheer up, this is likely to around 4 to 5 billion years from now.)