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.2025 January 7 
A New Year's Aurora and SAR Arc Image Credit & Copyright: Alessandra Masi Explanation: It was a new year, and the sky was doubly red. The new year meant that the Earth had returned to its usual place in its orbit on January 1, a place a few days before its closest approach to the Sun. The first of the two red skyglows, on the left, was a red aurora, complete with vertical rays, caused by a blast from the Sun pushing charged particles into Earth's atmosphere. The second red glow, most prominent on the far right, was possibly a SAR arc caused by a river of charged particles flowing across Earth's atmosphere. Although both appear red, the slight color difference is likely due to the aurora being emitted by both oxygen and nitrogen, whereas the higher SAR arc was possibly emitted more purely by atmospheric oxygen.The featured image was taken on January 1 from near Pieve di Cadore in Italy. Portal Universe: Random APOD Generator Tomorrow's picture: supernovas (plural) <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Amber StraughnSpecific rights apply.NASA Web Privacy,Accessibility, Notices; A service of:ASD atNASA /GSFC, NASA Science Activation& Michigan Tech. U.
