Borrego Lights

June 21, 2005


Provided by: Dennis Mammana
Summary authors & editors: Dennis Mammana

How often have you seen a display of the aurora borealis with a palm tree in the foreground? Because of a particularly strong coronal mass ejection from the Sun during the pre-dawn hours of May 15, 2005, the entire continental U.S. was treated to a magnificent auroral display. The aurora is caused by charged particles blasted from the Sun. In essence, when these particles become captured by the Earth’s magnetic field, they spiral down toward the north and south poles and collide with gases (primarily nitrogen and oxygen) in the upper atmosphere. Where this occurs the gasses begin to glow a variety of colors but mostly green and red.

Here in the southwestern desert near Borrego, California, the lights appeared to the eye as a diffuse, colorless glow but with distinct rays that towered vertically up to 30 degrees above the northern horizon. The camera, however, picked up the real colors of this display. The last auroral display easily visible from the southern U.S. occurred during the pre-dawn hours of July 27, 2004. While we tend to think of the northern lights as a winter-time phenomenon, in the mid latitudes, they can be observed even at the summer solstice.

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