"These particles, or aerosols, scatter sunlight as it passes through the air, which in a combination with the absorption of light by the ozone layer, gives sunrises and sunsets that purple ink, "the release says.
In a normal, non-volcanic sunset, light from the sun has to travel through a significant amount of Earth's atmosphere, and blue light scatters off of aerosols it encounters. This means less blue light reaches our eyes from directions near the sun, causing the skies to appear orange and red.
When volcanic aerosols are present in the stratosphere, blue light scattered from aerosols closer to the Earth's surface can scatter again, this time towards our eyes and cameras. This blue light mixes with the red light already coming from the sun, giving the sky a purple color.
Lars Kalnais, a research associate at the Laboratory for Atmospheric and Space Physics at the school, led the project and said this eruption
"A really big eruption would have a major impact on humanity," Kalnais said in the news release.
"There were crop failures all over the world, and there was ice in rivers in Pennsylvania that didn't melt until June, "said Kalnays.
That is one reason why his team is conducting research after the Raikoke eruption. Preliminary data collected are far-light shows that some aerosol layers in the stratosphere were 20 times thicker than normal in the wake of the eruption, according to a news release.
"It makes you realize that you don't have to travel a whole lot of aerosols into the stratosphere to change its composition," Kalnays said. "This was a relatively small volcanic eruption, but it was enough to impact most of the northern hemisphere."
The group's research is slated to be published later this year.