4th of July: When earth will be farthest from sun!

* The Earth reaches a point called Aphelion on its orbit on July 4, 2011 and will be farthest from Sun than on any other day in 2011*



On 4th of July, 2011, as United States commemorates the adoption of Declaration of Independence, there is another major event happening around planet Earth on the same day.





Earth at Aphelion is farthest to Sun while it is closest to Sun at a point called Perihelion. Though our planet typically reaches Aphelion and Perihelion in July and January respectively, the actual dates vary from year to year.



This year, Aphelion falls on Independence Day in the USA on 4th of July when earth will be at 94,511,923 miles (152,102,196 kilometres) from the sun, National Geographic News reported.



This year's perihelion was on January 3, when Earth was 92,955,807 miles (149,597,870 kilometres) from the Sun, it said.



According to Roy Spencer of the Global Hydrology and Climate Centre in Huntsville, Alabama, sunlight falling on Earth is about 7 percent less intense in July than it is at our closest approach to the Sun in January.



Then, why do we still feel the summer heat in July?



That's because Earth's seasons are determined by its tilt and not by its distance from the Sun, supporting German astronomer Johannes Kepler's Law according to which, "All planets in our solar system travel around the Sun in elliptical orbits."



"Continents and oceans aren't distributed evenly around the globe. There's more land in the northern hemisphere and more water in the south. During the month of July, near the start of northern summer, the land-crowded northern half of our planet is tilted toward the Sun. Earth's temperature (averaged over the entire globe) is slightly higher in July because the Sun is shining down on all that land, which heats up rather easily," Spencer was quoted as saying by NASA Science News.





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