The Sun's surface is about 10,000 degrees Fahrenheit. The thin atmosphere above it, the corona, runs at upwards of 2 million. NASA's own writers say it happens in defiance of all logic, and NASA's Parker Solar Probe flew into that atmosphere to find out why.

In this episode: the green line seen during an eclipse in 1869 that started the puzzle. Why reaching the Sun takes 55 times more energy than reaching Mars, and how the probe used Venus as a brake. Why a spacecraft does not melt in a place that is millions of degrees: the difference between temperature and heat. Then Beyond the Obvious: the Sun has no solid surface, but its atmosphere has an edge, and that edge is wrinkled. Shrink the trip from Earth to the Sun to a football field, and Parker flies to the four-yard line. We follow the magnetic kinks called switchbacks to where they begin, go through the two main theories for the heat, and explain what a 2024 result with Solar Orbiter did answer, and what it did not. The question we came for is still open, and we say so.

Every figure comes from NASA, ESA and arXiv pages, linked in the video description on YouTube. Where the sources don't explain something, we say so.

Watch the video edition: https://www.youtube.com/watch?v=7Xbw72kfiKM

Narration: synthetic voice. Research, writing and editing: human work. Echoes of the Void.