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Thursday, February 20, 2014

LIGHT OF THE STARS TRAVEL TO THE EARTH


And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. And God set them in the firmament of the heaven to give light upon the earth, And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good. (Gen.1:16-18)

The Bible is mention about God created the lesser light that rule the night ,God made the STARS to give light upon the earth Light travels at 300,000 kilometers per second or 186,000 miles per second. The time it takes for light from stars to reach us is the distance to the star divided by this speed. 


A light-year (symbol: ly), sometimes written light year or lightyear is an astronomical unit of length (not time) equal to just under 9.5 trillionkilometres (or about 6 trillion miles). As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year.


The light-year is most often used when expressing distances to stars and other distances on a galactic scale, especially in non-specialist andpopular science publications. The unit usually used in professional astrometry is the parsec (symbol: pc, approximately 3.26 light-years; the distance at which one astronomical unit subtends an angle of one second of arc).

That's an interesting question. Light travels at 300,000 kilometers per second or 186,000 miles per second. The time it takes for light from stars to reach us is the distance to the star divided by this speed. The nearest star to us is the Sun and it takes about 8.3 minutes for its light to reach us here on Earth.

Other stars are so much farther away that it is convenient to express the distance to them in units of the distance traveled by light in one year. This unit is called a light year. The next closest star to us is Proxima Centauri. This star is 4.3 light years away which means that light from it takes 4.3 years to reach us. Our galaxy is about 100,000 light years across. This means that it can take tens of thousands of years for light from some stars in our galaxy to reach us. For stars that we can see in nearby galaxies it can take millions of years. The farthest objects we can see are quasars. They are so distant that the light we see from them today left billions of years ago
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