Saturday, June 18, 2011

Summer Solstice Celebrated

Summer Solstice Celebrated, The Cassini Mission celebrates Earth's summer solstice (for the Northern hemisphere).

The summer solstice occurs at the moment the earth's tilt toward from the sun is at a maximum. Therefore, on the day of the summer solstice, the sun appears at its highest elevation with a noontime position that changes very little for several days before and after the summer solstice. In fact, the word solstice comes from Latin solstitium or sol (the sun) + -stit-, -stes (standing). The summer solstice occurs when the sun is directly over the Tropic of Cancer, which is located at 23.5° latitude North, and runs through Mexico, the Bahamas, Egypt, Saudi Arabia, India, and southern China. The sun will be directly over the Tropic of Cancer at 1116 am MDT on June 21, 2011. For every place north of the Tropic of Cancer, the sun is at its highest point in the sky and this is the longest day of the year.

There are two times of the year when the Earth's axis is tilted neither toward nor away from the sun, resulting in an equal amount of daylight and darkness at all latitudes. These events are referred to as equinoxes and occur near March 21 (Vernal Equinox) and near September 21 (Autumnal Equinox). At the equator, the sun is directly overhead at noon on the two equinoxes. The Vernal Equinox occurred at 521 pm MDT on March 21, 2011. The Autumnal Equinox will occur at 304 am MDT on September 2, 2011.

Summer Solstice CelebratedJPL Image Use Policy, Unless otherwise noted, images and video on JPL public web sites (public sites ending with a jpl.nasa.gov address) may be used for any purpose without prior permission, Unless otherwise noted in the caption information for an image, the credit line should be "Courtesy NASA/JPL-Caltech.

NASA still images, audio files and video generally are not copyrighted.

If the NASA material is to be used for commercial purposes, especially including advertisements, it must not explicitly or implicitly convey NASA's endorsement of commercial goods or services. If a NASA image includes an identifiable person, using the image for commercial purposes may infringe that person's right of privacy or publicity.

Generally speaking, works created by U.S. Government employees are not eligible for copyright protection in the United States. See Circular 1 "COPYRIGHT BASICS" PDF from the U.S. Copyright Office.

TEXT CREDIT: National Oceanic and Atmospheric Administration

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