Auroras, those shimmering lights we see in the sky, look amazing from Earth. But when an astronaut looks at them from space, they look even more stunning.
On February 28, NASA astronaut Josh Cassada tweeted a breathtaking photo of green auroras dancing around the Earth’s far north. He took this picture from the International Space Station, which orbits around 250 miles above the Earth.
While we might recognize the green glow of auroras, Cassada’s view from space shows how enormous and impressive they really are. They stretch hundreds to thousands of miles around the Earth’s poles.
The Northern Lights (Via Aaron Taylor/Shutterstock)
Auroras, also called northern lights in the Northern Hemisphere, happen when charged particles from the sun hit molecules in the Earth’s atmosphere. This interaction makes the molecules glow. Oxygen molecules emit green light, nitrogen emits red or pink light, and hydrogen and helium give off blue and purple light.
Auroras usually appear at high latitudes because solar particles follow Earth’s magnetic field lines, which end at the North and South poles. But when the sun sends out a big burst of plasma called a coronal mass ejection (CME), auroras can be seen at lower latitudes too.
Recently, the sun has been quite active. On February 26 and 27, two CMEs hit Earth, likely causing the widespread auroras that Cassada saw from space.
