wtf

Looks like time travel is possible… for particles of light.

Using a photon, physicists have managed to simulate quantum particles traveling through time. Studying the photon's behavior could help scientists understand some inexplicable aspects of modern physics.

"The question of time travel features at the interface between two of our most successful yet incompatible physical theories — Einstein's general relativity and quantum mechanics," University of Queensland's Martin Ringbauer says in a news release. "Einstein's theory describes the world at the very large scale of stars and galaxies, while quantum mechanics is an excellent description of the world at the very small scale of atoms and molecules."

Scientists in China say they have successfully grown a human tooth using stem cells taken from urine. Researchers say the technique could one day be used as a way to replace teeth lost through aging and poor dental hygiene, with the added bonus that urine is deemed a less controversial source of stem cells than human embryos.