Expired milk seen under the microscope! By: Kyu Been Lee

"WHAT IS THAT??? IS IT LIVING??" are some questions you may be asking yourself when watching this video.
However, don't panic! These aren't living organisms inhabiting the milk. Rather, they're a movement of particles also known as the Brownian motion.
True, it looks realistic. When I saw it too, I began worrying as well. However, it is just a random movement of particles because of molecules of another medium (outside particles) pushing the inner particles that are in the fluid.