The Sun's atmosphere is hundreds of times hotter than its surface - here's why (Conversation)

[eppur_se_muova]

May 24, 2021 11.16am EDT

By Marianna Korsos, Aberystwyth University and Huw Morgan, Aberystwyth University

The visible surface of the Sun, or the photosphere, is around 6,000°C. But a few thousand kilometres above it – a small distance when we consider the size of the Sun – the solar atmosphere, also called the corona, is hundreds of times hotter, reaching a million degrees celsius or higher.

This spike in temperature, despite the increased distance from the Sun’s main energy source, has been observed in most stars, and represents a fundamental puzzle that astrophysicists have mulled over for decades.

In 1942, the Swedish scientist Hannes Alfvén proposed an explanation. He theorised that magnetised waves of plasma could carry huge amounts of energy along the Sun’s magnetic field from its interior to the corona, bypassing the photosphere before exploding with heat in the Sun’s upper atmosphere.

The theory had been tentatively accepted – but we still needed proof, in the form of empirical observation, that these waves existed. Our recent study has finally achieved this, validating Alfvén’s 80 year-old theory and taking us a step closer to harnessing this high-energy phenomenon here on Earth.
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more: https://theconversation.com/the-suns-atmosphere-is-hundreds-of-times-hotter-than-its-surface-heres-why-161392

[Sneederbunk]

1. Therefore, when approaching the Sun, put on the sun block early.