Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2023 July 30
A bright green spiral aurora is seen in a break in the 
clouds before a purple background. The foreground contains 
green grassland and a circular lake.
Please see the explanation for more detailed information.

Spiral Aurora over Icelandic Divide
Image Credit & Copyright:

Explanation: Admire the beauty but fear the beast. The beauty is the aurora overhead, here taking the form of a great green spiral, seen between picturesque clouds with the bright Moon to the side and stars in the background. The beast is the wave of charged particles that creates the aurora but might, one day, impair civilization. In 1859, following notable auroras seen all across the globe, a pulse of charged particles from a coronal mass ejection (CME) associated with a solar flare impacted Earth's magnetosphere so forcefully that it created the Carrington Event. This assault from the Sun compressed the Earth's magnetic field so violently that it created high currents and sparks along telegraph wires, shocking many telegraph operators. Were a Carrington-class event to impact the Earth today, speculation holds that damage might occur to global power grids and electronics on a scale never yet experienced. The featured aurora was imaged in 2016 over Thingvallavatn Lake in Iceland, a lake that partly fills a fault that divides Earth's large Eurasian and North American tectonic plates.

Almost Hyperspace: Random APOD Generator
Tomorrow's picture: moon over mars


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