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→Earth Information: third planet from the Sun - 40,008 kilometers in diameter, pole to pole
== Earth Information ==
== Earth Information ==
The '''Earth''' is the third planet from the Sun. It is (24,800 miles) 40,008 kilometers in diameter, pole to pole and slightly larger around the equator. [[http://geography.about.com/library/faq/blqzcircumference.htm]] The reason its metric diameter is so close to the "round number" of 40,000 is that the French defined the [[kilometer]] as 1/10,000th the distance from the equator to the [[North Pole]].
The Earth orbits at an average distance of about 93 million miles (150 million km) from the Sun in an almost circular orbit. It takes light (and other forms of electromagnetic radiation) approximately 500 seconds to travel from the Sun to the Earth, i.e. the distance can also be stated as "500 light-seconds." The distance to nearby stars is made by measuring the stellar [[parallax]] between observations when the earth is at opposite ends of its orbit, so the earth's orbit itself is a measuring stick for astronomical distances, and is known as the ''astronomical unit'' (A. U.) It is worth noting that if the Earth were slightly closer to the Sun, it would be too hot for life (just as Venus is) while if Earth were slightly further away from the Sun, water would freeze and life would be impossible.
The Earth orbits at an average distance of about 93 million miles (150 million km) from the Sun in an almost circular orbit. It takes light (and other forms of electromagnetic radiation) approximately 500 seconds to travel from the Sun to the Earth, i.e. the distance can also be stated as "500 light-seconds." The distance to nearby stars is made by measuring the stellar [[parallax]] between observations when the earth is at opposite ends of its orbit, so the earth's orbit itself is a measuring stick for astronomical distances, and is known as the ''astronomical unit'' (A. U.) It is worth noting that if the Earth were slightly closer to the Sun, it would be too hot for life (just as Venus is) while if Earth were slightly further away from the Sun, water would freeze and life would be impossible.