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.

September 4, 1997

Rivers in the Sun
Credit: SOHO, MDI, Stanford U., ESA, NASA

Explanation: The surface of the Sun is shifting. By watching sunspots, it has long been known that our Sun rotates. It was also known that the centre of the Sun rotates faster than the poles. Now, recent measurements by the Solar Oscillations Investigations group of the SOHO Observatory have found that the surface of the sun moves in other ways, too. Hot, electrically charged gas flows along and beneath the Sun's surface as depicted in the above computer generated diagram. The speed of these solar rivers is false-colour coded with red hydrogen moving faster than blue. Over the course of a year plasma moves from the equator to the poles, while internal eddies circulate gas from deep inside the Sun. One surprise is the similarity to the motion of air in the Earth's atmosphere - indicating that scientists might learn more about Earth's global weather by studying the Sun.

Tomorrow's picture: Apollo 17: Boulder on the Moon

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.