8 Biggest, Weirdest Mysteries In Space

7. Why Is The Sun's Corona So Hot?

Solar Eclipse 2015

The sun, as you may well have gathered by now, is pretty hot stuff.

At its core, immense pressure caused by the force of gravity, results in a temperature of 15 million degrees celsius. This temperature steadily drops as you get closer towards the surface (well, not you personally, as the trip would probably render you unable to read articles on the internet), dipping to a positively balmy 4,320°C by the time you hit the chromosphere.

This is all to be expected, but then things heat up again dramatically as you enter the corona - the outer part of the sun's atmosphere that is only visible during a solar eclipse. Here, temperatures soar to 2 million degrees celsius, and no one is sure how or why.

Whilst we're on the subject of whacky solar temperatures, the sun’s south pole cooler than the north pole and we, likewise, can't figure out why this should be.

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