The sun is primarily composed of hydrogen and helium. Hydrogen is the most abundant element of the Earth’s closest star, representing 71 percent of its mass. Helium is the second most abundant element in the sun, representing about 27 percent of its mass. Oxygen, carbon, nitrogen, silicone, magnesium, neon, iron and sulfur combine to form about 1 percent of the sun’s mass.
Scientists study the components of the sun by analyzing the spectrum of light it gives off. The same technique works for stars, but because the sun is so much closer, scientists can collect better data. While this technique gives scientists excellent data about the outer layers of the sun, some details about the inner core remain unknown.
The sun is a flaming ball of superheated gas, about 864,000 miles in diameter. Fueled by intense nuclear reactions deep in its core, the sun reaches astonishingly hot temperatures as it converts hydrogen into helium. The sun’s surface reaches more than 10,000 F, but the core is much warmer, reaching up to 28 million F. Eventually, the sun will run out of hydrogen in its core, and, eventually, the nuclear process will stop. The sun has burned through about half of its helium, but it should continue to light the sky for another 5 billion years.