In today's image, we see the spiral galaxy known as M100 - this is an example of what is called a grand design spiral galaxy for its majestic spiral arms. We not the blue and pink color of the spiral arms. The blue is the light of many massive, hot blue stars that have formed within the spiral arms. The pick is the glow of hydrogen gas that is energized by the ultraviolet light from these stars.

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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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