August 14, 2006
On the day you were born, the universe did what it has always done best: transformed chaos into beauty.
Cosmic Rays
Birthday · August 14, 2006
A little universe, just for you
Your date.
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APOD published August 14, 2006. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
Have you ever been hit by a beam of high energy particles from above? Surely you have -- it happens all of the time. Showers of high energy particles occur when energetic cosmic rays strike the top of the Earth's atmosphere. Cosmic rays were discovered unexpectedly in 1912. It is now known that most cosmic rays are atomic nuclei. Most are hydrogen nuclei, some are helium nuclei, and the rest heavier elements. The relative abundance changes with cosmic ray energy -- the highest energy cosmic rays tend to be heavier nuclei. Although many of the low energy cosmic rays come from our Sun, the origins of the highest energy cosmic rays remains unknown and a topic of much research. This drawing illustrates air showers from very high energy cosmic rays. Cosmic rays may even be important to Earth's weather -- common lightning may be triggered by passing cosmic rays.