Purple aurora spotted in Canada, may be new discovery
Monday, February 8, 2016, 8:02 PM - Alberta sky watchers were treated to a rare spectacle Sunday night: For a brief moment in a time, a rare type of aurora borealis lit up the sky.
An image of the phenomenon was captured by Darlene and Theresa Tanner, who then posted it to Facebook and Twitter.
Northern lights -- or aurora borealis -- occur when solar particles collide with the Earth's atmosphere. Their colour variety results from the presence of different types of gas particles, and the colour of an aurora is dependent on the wavelength of light that's emitted.
Tanner described the light in her photo as a 'proton arc' -- i.e., a rare form of aurora caused by heavier, more energetic protons from the Sun streaming down into the atmosphere, but Jason Ahrns, an aurorologist with the University of Alaska Fairbanks Geophysical Institute says in a September Facebook post that proton arcs tend to show up wide, dim, green and featureless.
"He isn't sure what these thin purple arcs are, but they could be a new discovery," says Weather Network science writer Scott Sutherland.
Scientists are currently analyzing photos like the one Darlene and Theresa took Sunday in an effort to better understand the phenomenon.
Sunday's aurora was spotted near Three Hills, Alta.