The Rogues' Gallery

SGU Science Pic Of The Week: Hydrogen Alpha Sun

Bob Novella July 7, 2015 3 Comments

This may be one of the most beautiful pictures of the sun that I have seen.

It was taken by astro-photographer Alan Friedman.

Now, if you were close enough to the sun to see it like this, it wouldn’t appear like the picture does (before screaming silently and burning to death). That’s because this image was taken with a special filter that humans never had a need to evolve. It’s called a Hydrogen Alpha filter and it is commonly used to produce stunning images of the sun. As the name implies, this filter weeds out much of the light emitted by the sun. This isn’t a problem because the sun is so bright that having enough light for a bright image is not an issue even if most of the light is filtered out.

The type of light this filter allows through (656.28 nanometers) is emitted by hydrogen atoms on the surface of the sun when a hydrogen electron drops from the third outermost orbit to the second outermost one.

I’m sure you noticed something else beautiful in the picture but also a little perplexing as well perhaps. There appears to be a big cloud high above the surface of the sun. This isn’t an ordinary earth-type cloud of course. It’s a detached solar prominence. This is the leftover material from a previous prominence. Since it is ionized gas, it follows the magnetic field lines of the sun, sometimes falling back down, sometimes permanently detaching and heading off into space.

This is the sun after all, so this ionized cloud is probably bigger than you think. It likely tips the scales at over 10 billion tons and is something like 60 times the size of the earth.

Thanks to my Bro Jay for sending me this amazing example of astro-photography