The aurora borealis lit up the sky in over Michigan. What people shared on social media

The aurora borealis lit up the night sky in Michigan on Monday and Tuesday, according to the NOAA’s Space Weather Prediction Center.

Here’s a look at what people shared online:

Social media posts from the Northern Lights

What are the northern lights?

The northern lights are caused by collisions between fast-moving particles (electrons) from space and the oxygen and nitrogen gas in the atmosphere, NASA said.

Why do the northern lights have different colors?

The color of the aurora depends on which gas is being excited by the electrons and on how much energy is being exchanged, NASA said.

Oxygen emits either a greenish-yellow light (the most familiar color of the aurora) or a red light; nitrogen generally gives off a blue light. The oxygen and nitrogen molecules also emit ultraviolet light, which can only be detected by special cameras on satellites.

When is the best time to see the northern lights?

If the weather is clear, the best aurora is usually visible within an hour or two of midnight, according to NOAA.

The agency maintains an aurora dashboard that should help skygazers track the phenomenon.

Can’t see the northern lights? Use your phone

If you’re having trouble seeing the northern lights with the naked eye, try using your phone camera in night mode and hold still while capturing the photo. You might be surprised at what’s dancing in the sky.

How can I find out when the northern lights will appear?

There are several sites that track northern lights.

NOAA’s Space Weather Prediction website shares information about the strength of solar storms, when they will reach Earth and where the northern lights may be visible, among other information.