THE SUN

THE SUN

The hot, incandescent ball of gas that we call the Sun provides Earth with life-sustaining heat and light, and dictates its seasons and climate. But, as awesome as the Sun seems to us, it is a fairly typical star-one of at least 200 billion in the Milky Way Alone.



A TYPICAL STAR
The Sun lies in the disc of the Milky Way, in a region where the average space between stars is about 8 light-years. Like more then 90 percent of all stars, the Sun is in a stable stage of its life. In its hot, dense core, nuclear-fusion reactions convert hydrogen into helium. This releases energy, which gradually makes its way to the surface, where it escapes into space, mostly as infrared radiation (heat) and light. The Sun's rate of energy production and its surface temperature have both stayed relatively constant for about 4.6 billion years-and will stay so for as long again, until the hydrogen runs out. The Sun will then swell into a red giant, increasing its energy output as it burns helium and destroying the inner planets. After ejecting its outer layers, it will end its days as a white dwarf.

SOLAR X-RAY

The bright areas in the X-Ray image show concentrations of hot plasma (ionized gas) in the corona, the Sun's outer atsmospheric layer. The dark patches are coronal holes - regions from which particles stream out and form the solar wind.

THE SUN IN VISIBLE LIGHT
This is sun's surface, or photosphere, as we see it. Although the Sun is gaseous throughout, its density increases so quickly with depth that the disc's edge looks sharp,albeit darker. The spots are cooler regions produced by the Sun's magnetic field.











Sumber : Space