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.

May 7, 1996

The Clouds of Neptune
Credit: H. Hammel (MIT) and NASA

Explanation: These Hubble Space Telescope (HST) images reveal glimpses of the dynamic atmosphere of Neptune, the Solar System's most distant gas giant planet. The first close-up of Neptune's clouds was provided by NASA's Voyager 2 spacecraft during its August 1989 flyby, giving a tantalizingly brief look. From its vantage point in Earth orbit, HST can patiently watch in detail as the planet's massive weather systems change over time. These three pictures, taken during October and November 1994 when Neptune was only 2.8 billion miles distant, show the planet's characteristic aqua-blue colored atmosphere highlighted by pink, high altitude clouds and streaked with dark bands. The aqua-blue color is caused by gaseous methane which absorbs red light. Here, the high altitude clouds were intentionally given a pink tint to indicate that they were imaged in near infrared light - in true color images they would appear white.

Tomorrow's picture: The Great Dark Spot: Gone But Not Forgotten

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Authors & editors: Robert Nemiroff (GMU) & Jerry Bonnell (USRA).
NASA Technical Rep.: Sherri Calvo. Specific rights apply.
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