APOD on Nostr: **Astronomy Picture of the Day** 04 August 2025 **Blue Arcs Toward Andromeda** Image ...
**Astronomy Picture of the Day**
04 August 2025
**Blue Arcs Toward Andromeda**
Image Credit & Copyright:
Ogle et
al.
What are these gigantic blue arcs near the Andromeda Galaxy (M31)? Discovered in 2022 by amateur astronomers, the faint arcs -- dubbed SDSO 1 -- span nearly the same angular size as M31 itself. At first, their origin was a mystery: are they actually near the Andromeda Galaxy, or alternatively near to our Sun? Now, over 550 hours of combined exposure and a collaboration between amateur and professional astronomers has revealed strong evidence for their true nature: SDSO 1 is not intergalactic, but a new class of planetary nebula within our galaxy. Dubbed a Ghost Planetary Nebula (GPN), SDSO 1 is the first recognized member of a new subclass of faded planetary nebulas, along with seven others also recently identified. Shown in blue are extremely faint oxygen emission from the shock waves, while the surrounding red is a hydrogen-emitting trail that indicates the GPN's age.
#APOD #SpaceStation #PlanetaryExploration #Space #MilkyWay
https://apod.nasa.gov/apod/ap250804.htmlPublished at
2025-08-04 04:10:04 GMTEvent JSON
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"content": "**Astronomy Picture of the Day**\n\n04 August 2025\n\n**Blue Arcs Toward Andromeda**\n\nhttps://apod.nasa.gov/apod/image/2508/M31Oxy_Collab_5415.jpg\n\nImage Credit \u0026 Copyright: \nOgle et \nal.\n\n\nWhat are these gigantic blue arcs near the Andromeda Galaxy (M31)? Discovered in 2022 by amateur astronomers, the faint arcs -- dubbed SDSO 1 -- span nearly the same angular size as M31 itself. At first, their origin was a mystery: are they actually near the Andromeda Galaxy, or alternatively near to our Sun? Now, over 550 hours of combined exposure and a collaboration between amateur and professional astronomers has revealed strong evidence for their true nature: SDSO 1 is not intergalactic, but a new class of planetary nebula within our galaxy. Dubbed a Ghost Planetary Nebula (GPN), SDSO 1 is the first recognized member of a new subclass of faded planetary nebulas, along with seven others also recently identified. Shown in blue are extremely faint oxygen emission from the shock waves, while the surrounding red is a hydrogen-emitting trail that indicates the GPN's age.\n\n#APOD #SpaceStation #PlanetaryExploration #Space #MilkyWay\n\nhttps://apod.nasa.gov/apod/ap250804.html\n",
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