ELI5: Explain Like I'm 5

Quantum foam

Quantum foam is what is happening in the tiny space all around us - it is the zip-zapping of particles that make up everything. The particles are so small that they are only visible when we use powerful pieces of equipment that help us to look at them. They whiz around at incredibly fast speeds, so it looks like a foamy, bubbly mess - like a bubble bath. This is why we call it quantum foam!