I bet you have noticed a star twinkling in the night sky—stars can shimmer because of Earth’s atmosphere or air. The turbulent air surrounding our planet affects the starlight, making it look like the star is sparkling! But did you know that even if we travelled outside our atmosphere, and paid close attention to the stars, we could still see many of them change brightness?

Many of the stars we see get brighter and even fainter over various periods of time. Some stars dim, brighten, dim again, and so on…in less than a second! Other stars take years to vary their brightness—and not because the star is dying. These stars are called “variable stars.”

Explore a different variable star each month in 360 degrees on YouTube, or watch them in a planetarium dome, with these shorts from Ball State University, the American Association of Variable Star Observers, and the International Planetarium Society.

Download any of the three to four-minute-long episodes for your dome for free at https://www.bsu.edu/web/planetarium/productions-and-show-leasing