Check out the sun. Pretty effing hot, huh? (it’s even better HUGE.)
You can thank Alan Friedman for some of these pictures – Alan’s a great photographer and amateur astronomer. I hope he sees himself as more than an amateur astronomer at some point, because, well, holy crap. Alan did something awesome while taking pictures of the sun – he stuck a filter in front of his camera that filtered light in the H-alpha spectrum (which is around 6562.8 Angstrom, or 656 nanometers).
Yeah. that is pretty ca-raaaaazy red.
In this image below, of four Balmer spectrum lines given off by Hydrogen being ionized, H-alpha is on the far right:
From the Discovery Blog, on how this whole process works:
The Sun’s surface puts out light at all wavelengths, but the surface isn’t solid. It’s a gas, and it tapers off with height. Normally, a thin gas in space emits light at very specific colors as electrons jump from one energy level to another in the individual atoms. But compressed gas in the thicker, denser part of the Sun mashes together all those energies, spreading them out, so it emits white light (that layer of the Sun is called the photosphere). Above that layer, where the gas is thinner (in a layer called the chromosphere), the hydrogen does emit light at specific colors. One of these, H-α, is in the red part of the spectrum, and in fact hot, thin hydrogen emits very strongly in H-α.
By plopping a filter in front of a telescope, you can block a lot of the light from the photosphere but let light from the chromosphere through. That’s what Alan Friedman did — he used a filter that let through a very narrow range of colors centered on H-α — to get this stunning picture. Well that, plus quite a bit of image processing! But everything you’re seeing there is real, and is happening on the Sun.
There are actually six Balmer hydrogen spectrum lines that exist, but two of them are in the ultraviolet spectrum, under 400 nm. All hydrogen atoms exhibit these spectra – so what astronomers do is they use the h-alpha waves to see which heavenly bodies that exhibit these waves. The resulting images look like these below.
(even better HUGE.)
(even better HUGE.)
Alan did all of this observing with his telescope – check this little thing out! Like the Little Engine that Could!
I couldn’t leave these images out – Here are some images from NASA’s Solar Dynamics Observatory, or SDO. SDO is one bad-mopho of a telescope that measures all kinds of goodies from the Sun. Check out the Solar Dynamic Observatory website as well, with images, video, and other amazing information. The one directly below here is of the surface of the sun – the white bar in the lower left corner represents five thousand kilometers.