(WITI/CNN) -- A solar storm racing towards Earth helped create quite the light show in the sky for parts of the northeast as well as places like Iceland, Norway and Finland.
Conditions made it difficult to see the Aurora Borealis in southeast Wisconsin. But take a look at tweets that went out Saturday from states like Maine, Vermont and New Hampshire.
Even astronaut Reid Wiseman got in on the action -- from space.
So what's a solar storm? Basically, the sun is a giant ball of gas: 92.1% hydrogen and 7.8% helium. Every now and then, it spits out a giant burst of gas that contains magnetic properties called a coronal mass ejection.
These ejections are sometimes associated with solar flares, the most explosive events in the solar system. The sun has released two ejections in the past few days, and both are linked to solar flares. NASA says the second flare is an X1.6 class, putting it in the most intense category.
The energy from those two ejections is now hitting Earth. Space weather experts aren't sure what this solar storm will do.
Earth's atmosphere usually protects us humans, but you might want to keep a flashlight handy. Solar storms can knock out power, interfere with GPS and radio communications -- including those on commercial airliners -- and damage satellites.