The SunPhotos courtesy of NASA.Structure of the SunThe Sun is a massive burning ball of gases held together by gravity. It is primarily composed of helium and hydrogen gases. The Sun has three main layers--the core, the radiative zone and the convective zone. The Sun's atmosphere is made up of the photosphere, chromosphere and corona.Sunspots are cooler, darker areas of gas on the Sun's surface. Solar FlaresSolar flares are enormous areas of extreme temperature on the Sun's surface, caused by magnetic fields. They typically occur near sunspots. The PhotosphereThe photosphere is the inner layer of the Sun's atmosphere. This gaseous layer is thick enough to be visible. When we look at the Sun, we are seeing the photosphere.The ChromosphereJust beyond the photosphere is a thin layer called the chromosphere, which has a reddish color. The chromosphere can be seen during a total solar eclipse when the Moon covers the Sun.The Sun's CoronaThe outer atmosphere of the Sun is called the corona. It is composed of gases and extends for millions of kilometers beyond the Sun. The corona can only be seen during a total solar eclipse.© Copyright NewPath Learning. All Rights Reserved. 94-4579Visit www.newpathlearning.com for Online Learning Resources.The Core & Nuclear FusionThe core at the center of the Sun produces the Sun's heat. This energy is produced by hydrogen nuclear fusion reactions. The Radiative ZoneEnergy produced in the Sun's core is carried to the Sun's surface in the form of light energy called photons. This energy moves from the core into a very dense radiative zone.The Convective ZoneThe outer layer of the Sun is called the convective zone. Hot gases in this layer rise toward the surface, where they become cooler and denser. The gases then descend back into the Sun. This circulating movement is called convection, and is similar to currents in the Earth's mantle.coresolar eclipsecoronachromosphereconvection currentsphotospherechromosphereflare
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