The Sun
Our Sun is a star that the
Earth orbits. It is a main sequence star, which means it is a middle
aged star. The Sun is alive as long as it has a supply of hydrogen to
transform into helium. Once the hydrogen is depleted, the Sun will
expand and die, leaving a planetary nebula and the Sun's core. The
planetary nebula eventually disperse into space, leaving a white dwarf
star. The dwarf star will cool and die.
The Sun has a chaotic
surface. There are three layers separating the surface from the core.
The inside layers of the Sun are the photosphere, the convective zone
and the radiative zone. The photosphere is made of hydrogen at the
temperature of 5500°C. Inside the convective zone there are swirling
currents taking heat to the photosphere. It is around 140,000 km thick.
The core energy passes through the radiative zone, which is around
380,000 km thick. The core is like a massive nuclear reactor where
hydrogen is transformed into helium.
There are many things
happening on the Sun's surface, such as solar flares, which are large
explosions happening in the chromosphere. Solar prominences are huge
jets of flaming hydrogen. They are held to the corona by the Sun's
magnetic field. Solar prominences can sprout from the Sun at great
speeds.They can reach a height of 500,000 km. Looped prominences occur
when the solar prominences form an arc. Sunspots occur in the
photosphere, and are caused by intense magnetic activity, which prevents
heat from the convective zone from traveling to the surface. Sunspots
appear to be darker because they are cooler, at only 2,700-4,200 °C.
The Sun constantly gives
off charged particles called the solar wind. When the charged particles
reach Earth's atmosphere, they interact with gases that causes the
particles to emit light. This light is most visible at the Earth's
poles, and is known as the aurora borealis, or nothern lights in the
nothern hemisphere. In the southern hemisphere they are known as the
aurora australis or the southern lights.
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