Nearly a million times brighter than the full Moon, with 99.9 percent of all the mass of our solar system, the Sun is the most extraordinary object in our sky. Yet from an astronomical standpoint it is an ordinary, common starΓÇöwhat astronomers call a main sequence G2V. It is mid-range in size, weight, and brightness: other starsΓÇÖ diameters range from about 1/100 to 100 times that of the Sun; their mass is anywhere from 8 percent to 100 times the SunΓÇÖs; and their brightness 1/1000 to several million times our home starΓÇÖs. The Sun has been stable for the last 4 to 5 billion years, and this steadiness has been essential to the formation and development of life. There are many more dramatic stars for astronomers to study, but if not for
