The Sun - Facts, Information and Pictures

The star at the center of our solar system is called the Sun.  The Sun is a white star, although it looks yellow from Earth.  Astronauts who have viewed the Sun from outside of Earth's atmosphere have all reported the Sun look white.  The reason why its looks yellow to us is because the blue spectrum of light is scattered in our atmosphere, hence a blue sky.  The Earth lies approximately 93 million miles from the Sun.  The sun provides the warmth that the Earth needs to be hospitable to life.  It creates the light that Earth-bound plants need for photosynthesis, it provides the warmth that causes water to exist in liquid form, but not too much such that the oceans boil away.

The Sun is huge and comprises 99.86 of all the matter in our solar system.  The Sun is a giant ball of gas that is held together by its own gravity.  This causes tremendous pressure, and thus tremendous heat.  The sun's core reaches 15 million degrees Celsius (about 27 million degrees Fahrenheit).  The Sun is comprised of hydrogen gas that undergoes thermonuclear fusion and fuses into Helium.

The outermost layer of the Sun is called the photosphere.  This is where the Sun's radiation escapes.  It takes light 8 minutes to reach the Earth from the Sun.  The photosphere's temperature reaches 5,500º Celsius (10,000º  Fahrenheit) and is the area in which sunspots form.  The areas above the photosphere are called the chromosphere and the corona.  Oddly enough, the temperature increases to 2 million degrees Celsius (3.5 million degrees Fahrenheit).  The Sun emits a solar wind of charged particles that extend to the outer limit of the solar system.  The solar wind blows at an incredible rate of 400 km/s (about 1 million miles per hour).