Aurora watch

Animated GIF of the two recent
solar flares, from spaceweather.com

The Sun emitted two large solar flares on Friday and Saturday, so there's a good chance we might see some aurorae (northern lights) over the next few days. That happens when the high-energy particles spewed out by the Sun hit Earth's magnetic field, get funneled down toward the north and south (magnetic) poles, and then enter the atmosphere and ionize the atoms they come into contact with. When those ions recombine, they emit light of many colors: usually green, but sometimes also red, pink, or blue. We can see these at night as sheets or curtains of eerie, flickering light.


It's easiest to see aurorae from more northern latitudes, but when there's a solar flare, the light display can sometimes be seen further south than usual. The website spaceweather.com keeps a real-time log of where the aurorae can currently be seen, and also posts viewers' pictures. It's worth keeping an eye on this site over the weekend. If it looks like we'll be able to see aurorae from Denver, you'll want to find a spot with a nice dark northern horizon. Let your eyes adjust to the dark and look for greenish light that looks sort of like thin clouds, except you can see stars through it and it shifts around faster than a cloud does. That'd make a great observing log entry! Have you ever seen the aurorae before?

A beautiful aurora shot from Norway by Andy Keen, www.aurorahunters.org
(posted on spaceweather.com)