I’ve seen images from the Sun in all different wavelengths of light. It looks very different across the electromagnetic spectrum, with some wavelengths making up more of the Sun’s total energy output than others. What’s always striking to me is seeing the images of the Sun that show its structure, including the strange and beautiful features of plasma that dance across it’s surface. A recent APOD captures just such a concept.
This image shows the Sun in Hydrogen Alpha, a wavelength of light at 656 nanometres. This is from the ionization of Hydrogen, where the electron is excited and transitions to a lower energy state.
The first thing I thought of when I saw this is how ‘hairy’ the Sun looks. It’s a response that 7-year-old me would have chosen, and it’s a knee-jerk reaction, but the longer I look at it, the more it makes sense to describe it that way. The ‘hair’ is the swirling filaments of plasma that are stirred up by convection currents and magnetic field activity. This is why the shapes are a bit different near the two sunspots at the bottom of the image – magnetic fields dictate the flow of plasma around them.
Arguably the best feature is the solar prominence visible from the horizon of the image, where the plasma has been blasted up from the surface of the Sun, and huge too! At 600,000 Km across, this prominence is larger than the Moon’s orbit around the Earth!
The amazing thing about this image is that it’s not from SOHO or SDO (Big NASA Solar Observatories), but from a backyard telescope setup with proper filters and a lot of skill at photography and post-processing. Well done!