Humans use lasers for everything from scanning barcodes and putting on light shows to performing delicate eye surgery and measuring the distances between objects in space.
![Chris Keane.](https://wpcdn.web.wsu.edu/wp-cas/uploads/sites/648/2019/05/keane_chris.jpg)
Cats also like to chase lasers, but I wasn’t sure how they worked. I asked my friend Chris Keane, a physics professor at Washington State University. Keane came to WSU from the National Ignition Facility at Lawrence Livermore National Laboratory where he helped work on a laser as big as a football stadium.