Today’s Astronomy Picture of the Day is a wonderful photo of a blue Sun (our Sun). The photo is converted blue to highlight the rapidly moving gases that end up looking like bristles on a carpet.

The description on the photo is particularly interesting, mainly this part:

Our Sun glows because it is hot, but it is not on fire. Fire is the rapid acquisition of oxygen, and there is very little oxygen on the Sun. The energy source of our Sun is the nuclear fusion of hydrogen into helium deep within its core. No sunspots or large active regions were visible on the Sun this day, although some solar prominences are visible around the edges.

I have always thought of the Sun as an object that was on fire, but now it actually makes sense to read that the sun is almost never on fire. It’s just very hot.