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Image of the solar corona in white light (outer circle, blue and white) and X-Rays (inner circle, red, yellow, and black) on April 22, 1994, courtesy of the High Altitude Observatory and the Yohkoh Science team. The dashed circle is the solar radius.
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Image courtesy of the High Altitude Observatory, National Center for Atmospheric Research (NCAR), Boulder, Colorado, USA. NCAR is sponsored by the National Science Foundation.The solar X-ray image is from the Yohkoh mission of ISAS, Japan.

The Solar Atmosphere

The visible solar atmosphere consists of three regions: the photosphere, the chromosphere, and the solar corona. Most of the visible (white) light comes from the photosphere, this is the part of the Sun we actually see. The chromosphere and corona also emit white light, and can be seen when the light from the photosphere is blocked out, as occurs in a solar eclipse. The sun emits electromagnetic radiation at many other wavelengths as well. Different types of radiation (such as radio, ultraviolet, X-rays, and gamma rays) originate from different parts of the sun. Scientists use special instruments to detect this radiation and study different parts of the solar atmosphere.

The solar atmosphere is so hot that the gas is primarily in a plasma state: electrons are no longer bound to atomic nuclei, and the gas is made up of charged particles (mostly protons and electrons). In this charged state, the solar atmosphere is greatly influenced by the strong solar magnetic fields that thread through it. These magnetic fields, and the outer solar atmosphere (the corona) extend out into interplanetary space as part of the solar wind.


Last modified February 6, 2008 by Jennifer Bergman.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF