SKYWATCH: Perihelion: An Annual Floating ‘Holiday’
This diagram shows perihelion, when the Sun is at location 3 and the Earth is at location 2 in its orbit around the Sun (in early January). When the Earth is at location 1, in its orbit around the Sun (in early July), this is known as aphelion. This diagram is not to true scale for the Earth-Sun system; it is only to explain perihelion and aphelion. (Diagram Source: Wikipedia.org )
It’s not Earth’s distance from the sun that makes hot weather in July; it’s the tilt of its rotational axis. In summer, the North Pole tilts toward the sun, causing sunlight to arrive from more nearly overhead, spreading out less on the ground. Plus, longer days give the sun more time to heat our hemisphere.
Earth’s oblong (elliptical) orbit brings it closest to the sun around New Year’s Day, but the exact date varies from year to year. Earth was at perihelion (closest point to the sun) around 5 p.m. on Jan. 4 in 2012; in 2013 it will be around 10 p.m. (Mountain Standard Time) on New Year’s Day.
Earth will be at perihelion (closest point to the Sun) at 12:00 Midnight Eastern Standard Time on Wednesday Morning, 2013 January 2 (night of January 1-2).
More - Link >>> http://magicvalley.com/lifestyles/recreation/skywatch-perihelion-an-annual-floating-holiday/article_a032985f-c2f8-54fd-bea2-8387bf627cef.html
Sources: Centennial Observatory of the College of Southern Idaho, Twin Falls Times-News.
Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://friendsofthezeiss.org >
Electronic Mail - < email@example.com >
About the Author: < http://buhlplanetarium.tripod.com/#GAW >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
Twitter: < http://twitter.com/
Facebook: < http://www.facebook.com/pages/
Blog: < http://spacewatchtower.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
* Adler Planetarium, Chicago:
* Astronomer, Educator, Optician John A. Brashear:
< http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
* Civil War Museum of Andrew Carnegie Free Library:
< http://garespypost.tripod.com >
* cable-car railway, Pittsburgh:
* Public Transit: