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 November 6
The night sky over a valley is shown complete with 
the central band of the Milky Way Galaxy crossing up from
 the lower left. On the right the sky just over the hill
glows an unusual red: aurora.
Please see the explanation for more detailed information.

Red Aurora over Italy
Image Credit & Copyright: Giorgia Hofer

Explanation: What was that red glow on the horizon last night? Aurora. Our unusually active Sun produced a surface explosion a few days ago that sent out a burst of electrons, protons, and more massive charged nuclei. This coronal mass ejection (CME) triggered aurorae here on Earth that are being reported unusually far south in Earth's northern hemisphere. For example, this was the first time that the astrophotographer captured aurora from her home country of Italy. Additionally, many images from these aurorae appear quite red in colour. In the featured image, the town of Comelico Superiore in the Italian Alps is visible in the foreground, with the central band of our Milky Way galaxy seen rising from the lower left. What draws the eye the most, though, is the bright red aurora on the far right. The featured image is a composite with the foreground and background images taken consecutively with the same camera and from the same location.

Aurora Album: Selected images sent in to APOD
Tomorrow's picture: devil on mars


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