Pulsating stars (so-called cepheids) have long been used as one of the best means to determine distances in astronomy. Needless to say, the devil is in the details. A team of astronomers has now studied the star “RS Pup” to measure its distance using light echoes - light from the star bouncing off surrounding material. If you’re interested in this, have a look at the press release or even the actual publication. But regardless of how interested you are in this, you will definitely want to watch the movie the researchers made, with time compressed into seconds, the star pulsating visibly, and material ejected from the outer layers of the star streaming into space (the black line masks the star so its brightness won’t overpower the camera).