Imaginea Astronomica a Zilei

Descopera cosmosul! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2001 April 11
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

Large Sunspot Group AR 9393
Credit: MDI, SOHO, ESA, NASA

Explicatie: (Edit) The largest sunspot group of the past ten years crossed the surface of the Sun late last month and early this month. The group was designated Active Region 9393 as it was the 9393rd region identified since counting officially began in 1973. The number of active regions on the Sun is high recently because the Sun is reaching the maximum of its current 11-year cycle of magnetic activity. The above time-lapse sequence shows AR 9393 as it evolved from 27 March to April 2 to become over 10 times larger than our Earth. Just after the end of the movie, on April 2, AR 9393 unleashed the largest solar flare of the last 25 years. Luckily, the flare was not pointed toward the Earth, or flare particles might have damaged satellites or even caused local electrical blackouts. Yesterday morning, however, a less powerful flare was ejected from a different sunspot group (AR 9415) toward Earth that has already caused radio interference. This and solar activity from Monday should cause significant aurorae over the next two nights. Will the above sunspot group remain as its region rotates back into view in a few days, or will it break up on the far side of the Sun? Currently, no one knows for sure.

Imaginea de maine: STS-1


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Autori & editori: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
Reprezentanti tehnici NASA: Jay Norris. Specific rights apply.
Un serviciu al: LHEA at NASA/ GSFC
& Michigan Tech. U.