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A closeup view of a typical pair of sunspots, with Earth superimposed to show scale.
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Original Windows to the Universe artwork by Randy Russell using images from the Royal Swedish Academy of Sciences (sunspot image) and NASA (Earth image).

Sizes of Sunspots

Sunspots are very large structures. Although they look small against the backdrop of the Sun, which has a diameter of 1.4 million km (870 thousand miles), most sunspots could swallow a planet. Many sunspots, like the ones shown in the image on this page, are as large as Earth! Most spots range in size from about 1,500 km (932 miles) to around 50,000 km (31,068 miles) in diameter. Occasionally gigantic sunspots the size of Jupiter appear on the Sun's "surface".

Astronomers believe some other stars also have spots. Young stars seem especially likely to have large numbers of starspots, and some of those may be immense.

Last modified September 6, 2005 by Jennifer Bergman.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA