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.

2024 May 15
Part of the Sun is pictured, oriented as the right
edge. The surface is textured like a carpet. Over the edge
a long multi-pronged prominence stands out. Behind the Sun
is the darkness of space. 
Please see the explanation for more detailed information.

AR 3664 at the Sun's Edge
Image Credit & Copyright: Sebastian Voltmer

Explanation: What did the monster active region that created the recent auroras look like when at the Sun's edge? There, AR 3664 better showed its 3D structure. Pictured, a large multi-pronged solar prominence was captured extending from chaotic sunspot region AR 3664 out into space, just one example of the particle clouds ejected from this violent solar region. The Earth could easily fit under this long-extended prominence. The featured image was captured two days ago from this constantly changing region. Yesterday, the strongest solar flare in years was expelled (not shown), a blast classified in the upper X-class. Ultraviolet light from that flare quickly hit the Earth's atmosphere and caused shortwave radio blackouts across both North and South America. Although now rotated to be facing slightly away from the Earth, particles from AR 3664 and subsequent coronal mass ejections (CMEs) might still follow curved magnetic field lines across the inner Solar System and create more Earthly auroras.

Gallery: Earth Aurora from Solar Active Region 3664
Tomorrow's picture: open space


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