Changes

'''Stars''' are extremely large, luminous bodies of gas at great distances. They are the most obvious features found in the [[universe]].  They are principally composed of [[hydrogen]] that is undergoing nuclear [[fusion]] to become [[helium]]. Our Sun is the nearest star to Earth, at a distance averaging 93 million miles. The Earth orbits the Sun in a period of approximately 365.25 days, and this defines the [[year]]. The diameter of the Sun, which is a typical star, is about 870,000 miles and its power output is about 10²⁶ watts. The temperature inside the Sun is estimated to be in excess of ten million degrees, and this is hot enough for [[nuclear reactions]] to occur.

'''Stars''' are extremely large, luminous bodies of gas. They are the most obvious features found in the [[universe]].  They are principally composed of [[hydrogen]] that is undergoing nuclear [[fusion]] to become [[helium]]. Our Sun is the nearest star to Earth, at a distance averaging 93 million miles. The Earth orbits the Sun in a period of approximately 365.25 days, and this defines the [[year]]. The diameter of the Sun, which is a typical star, is about 870,000 miles and its power output is about 10²⁶ watts. The temperature inside the Sun is estimated to be in excess of ten million degrees, and this is hot enough for [[nuclear reactions]] to occur.

==The Magnitude scale of brightness==

==The Magnitude scale of brightness==