APOD - The Pleiades in Red and Blue
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 July 8
Image Credit & Copyright: Ogetay Kayali (Michigan Tech U.) Text: Ogetay Kayali (Michigan Tech U.)
Explanation: If you have looked at the sky and seen a group of stars about the size of the full Moon, that's the Pleiades (M45). Perhaps the most famous star cluster in the sky, its brightest stars can be seen even from the light-polluted cities. But your unaided eye can also see its nebulosity -- the gas and dust surrounding it -- under dark skies. However, telescopes can catch even more. The bright blue stars of the Pleiades, also known as the Seven Sisters, light up their surrounding dust, causing it to appear a diffuse blue that can only be seen under long exposures. But that's not all. The cosmic dust appears to stretch upward like ethereal arms. And the entire structure is surrounded by a reddish glow from the most abundant element in the universe: hydrogen. The featured image is composed of nearly 25 hours of exposure and was captured last year from Starfront Observatory, in Texas, USA
Tomorrow's picture: open space
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Amber Straughn Specific rights apply.
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& Michigan Tech. U.
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