An impressive aurora borealis lit up the night skies over Canada and northern sections of the U.S. early Tuesday to the delight of many.
The phenomena also apparently delighted an astronaut on board the International Space Station.
Josh Cassada tweeted a photo of the aurora from his perch on board the International Space Station. Because the phenomenon occurs in the upper reaches of the Earth’s atmosphere, the photo shows a green halo surrounding the Earth.
“Absolutely unreal,” he said.
Auroras are caused by the solar wind interacting with Earth’s magnetic field. These auroras tend to navigate around the Earth’s magnetic poles.
“The solar wind particles funnel around to the long tail of the magnetosphere, where they become trapped,” NASA said. “When magnetic reconnection occurs, the particles are accelerated toward Earth’s poles. Along the way, particles can collide with atoms and molecules in Earth’s upper atmosphere, an interaction that provides the atoms with extra energy which is released as a burst of light. These interactions continue at lower and lower altitudes until all the incoming energy is lost. When we see the glowing aurora, we are watching a billion individual collisions, lighting up the magnetic field lines of Earth.”
Cassada is among four members of NASA and SpaceX’s Crew-5 mission.