Sun is the 5-billion-year-old star that sustains life here on Earth.
With a core reaching a fiery 16 million ° C the Sun's surface temperature is 5,503° C, so hot that no solid or liquid can exist. Sunspot, dark spot on this images, are lower temperature (3,700° C) than that of the surrounding photosphere.
Sunspots thus appear relatively dark. Sunspots are magnetic regions on the Sun with magnetic field strengths thousands of times stronger than the Earth's magnetic field.
With diameter of 1,390,000 km (110x Earth), the Sun contains more than 99 percent of the entire mass in the solar system. Earth is a little less than 150 million kilometers away from the Sun.