Why does the Sun’s corona get much hotter than its surface?

The Sun’s corona is the thin outer atmosphere seen during total solar eclipses. It is far hotter than the photosphere, the visible surface, which is about 5,500 degrees Celsius, while the corona can reach around 1 to 3 million degrees Celsius. Scientists think magnetic waves and magnetic reconnection help transfer energy upward from the Sun’s lower layers into the corona. This heating does not happen evenly, which is why the corona has complex loops and streamers. Although the details are still being studied, magnetic processes are the leading explanation.