ELI5: Explain Like I'm 5

Fringe science

Fringe science is science that is on the edge of accepted knowledge. It usually has ideas that are not proven and accepted by the majority of scientists. Fringe science usually has theories that don't fit into current mainstream scientific theories. For example, some fringe science ideas suggest that people can communicate with aliens, or that time travel is possible. These ideas are not accepted by the scientific community and so they can be considered fringe science.