Figure 2:
A cut-away view of the Sun showing the convection zone, the
photosphere, the chromosphere, many surface features and localized
atmospheric eruptions like sunspots, flares and prominences. Courtesy of
Gene Parker.
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Figure 2:
A cut-away view of the Sun showing the convection zone, the
photosphere, the chromosphere, many surface features and localized
atmospheric eruptions like sunspots, flares and prominences. Courtesy of
Gene Parker.
The Sun is a fairly average, middle-aged (some 4.5
billion years old)
star which is currently composed of approximately 72% hydrogen, 26% helium
and 2% of all other chemical elements (most notably those up to oxygen)
in gaseous form. The source of the Sun's brightness (and that of other
stars) is due to nuclear chemical reactions occurring in its innermost
parts, where the temperature is 15,000,000 Kelvin (27,000,000
F).
The Sun is 1,400,000 kilometers (900,000 miles) in diameter and liberates
about 3.86
watts of energy from its surface.
This energy, the solar luminosity, translates to about 1368 watts per
square meter at the orbit of the Earth.
