From Ed Prior
In your article about Stephen Fry’s team of “elves”, who dig out facts for the QI quiz show, James Harkin mentions that he “read in Â鶹´«Ã½ that the corona of the sun is hotter than the centre” (20/27 December 2014, p 40).
I’m not sure which article he was referring to, but the temperature of the sun’s core is about 15 million °C, whereas the corona – the outer atmospheric layer – is at around 5 million °C. It is true, however, that the corona is much hotter than the surface of the sun, which is only in the thousands of degrees. I believe that is what Harkin meant.
Why the sun’s atmosphere is so much hotter than the surface is still a mystery.
Poquoson, Virginia, US
