In today's image, we see a remnant left behind by a supernova that exploded about 400 years ago. It is considered a double detonation because an initial explosion on the surface of the white dwarf star causes a compression in the star which then triggers another explosion.

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This Podcast is an authorized New Media Mirror Site for APOD. You can access the image and website directly at: Astronomy Picture of the Day. You can use the archive link below the image to select the photo corresponding to the date of this podcast.

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