We may never see practical time travel in our lifetimes, if it’s possible at all. However, a team at the University of Queensland has given the Doc Browns of the world a faint glimmer of hope by simulating time travel on a very, very small scale. Their study used individual photons to replicate a quantum particle traveling through a space-time loop (like the one you see above) to arrive where and when it began. Since these particles are inherently uncertain, there wasn’t room for the paradoxes that normally thwart this sort of research. The particle couldn’t destroy itself before it went on its journey, for example.
As you might have gathered from the “simulation” term, sci-fi isn’t about to become reality just yet. The scientists haven’t actually warped through time — they’ve only shown how it can work. It could take a long time before there’s proof that whole atoms and objects can make the leap, let alone a real-world demonstration. Should you ever step into a time machine, though, you’ll know where it all started… and ended.