No one human can be attributed to discovering the sun, as it has existed longer than humans and is readily visible to the naked eye. However, many of the features of the sun were discovered by the Italian astronomer Galileo Galilei in the late 16th and early 17th centuries.
Galilei was able to see sunspots, solar flares and solar prominences with the first low-powered telescopes. Galilei's "Letters on Sunspots" was published in 1613 amid debate from the German Jesuit astronomer Christoph Scheiner.
Scientists theorize that the sun formed approximately 4.6 billion years ago from a rapidly rotating cloud of gas.