Okay, weve talked about all that whizzy tech, but how about we get stuck into that big old elephant in the room: Time travel. Although, technically, time travel was invented in the 80s according to BTTF, but never mind that for now. We can always go back and give them the technology if we really want. What if I told you that time travel is possible? Sort of. Time is not as straight forwards as you might think (its a bit more wibbly-wobbly). The passage of time isnt fixed and is influenced (broadly speaking) by two things: Your relative velocity and your proximity to a gravitating mass. This is a principle of relativity known as Time Dilation, making it technically possible for Doc Brown and co to travel from 1985 to 2015, so long as the DeLorean could hit some truly face-melting speeds (say, just below the speed of light). If you travel very, very fast approaching the speed of light, not only will you rack up a fine collection of speeding tickets, but time will pass much more slowly for you relative to the rest of the world. This is all great, but its not the same as jumping in your DeLorean and jumping about time like a trampoline. However, because time travel isnt prohibited by any physical laws, theres nothing stopping us from harnessing this power in our future tech. Thats forwards time travel, backwards time travel is a bit trickier and is still hotly debated by physicists. Some believe that it is straight up prohibited by the laws of causality, some say that it would be impossible to travel further back than the invention of the first time machine, and some say that you could travel back in time using wormholes (this involves a complicated process of creating a wormhole, attaching it to the back of your spaceship, dragging it around at lightspeed and then jumping back through it. Simple). Perhaps one of the biggest arguments against time travel is that we havent met any time travellers yet. Professor Stephen Hawking once announced that he would be holding a gathering for time travellers. No one turned up. Were there any other predictions Back To The Future got right (or terribly wrong)? Share anything we missed down in the comments.
