Science!: Giant Squid Sex and Whale Nostrils

Lauren Admire | 26 Jul 2010 21:00

I'd like to preface this last entry with a note: Physics is not my strong point. I can't quite wrap my head around everything about this news story, but it's incredibly interesting and I wanted to share it. That being said, here we go!

You're probably most familiar with the grandfather paradox from Marty McFly's adventures in Back to the Future, wherein he must take caution not to accidentally do something that will cause him to have never existed in the first place. Time machines are cool and all, but that's a pretty big gamble to take just to go back and laugh at a pod of dodos.

Thankfully, some clever MIT professor and colleagues have fixed this for us, allowing us to theoretically travel to any period of time in relative safety (grognards hoping to visit a real-life wargame, you're on your own). There are a lot of complicated equations and mind-blowing quantum mechanics theories involved here, so I will be substituting the phrase "fancy science magics" for anything I don't quite understand.

Physicists used the theories of postselection and quantum teleportation to make fancy science magics a possibility. Postselection is a way of solving a complex problem with multiple variables by allowing the variables to select a random value and then "postselecting" for the one combination that will make the equation true. Though not a perfect example, it sounds a lot like taking Schrodinger's cat and shooting it in order to get the desired outcome.

Coupled with postselection is the theory of quantum teleportation - using fancy science magics, it's possible to produce a quantum state in space that had previously existed in an entirely different part of space. In other words, you could transport a particle - and therefore, probably groups of particles back in time. In the future.

So, how does this solve the grandfather paradox? In two ways. First - it doesn't involve the bending of spacetime at all, which is good, because I wouldn't be able to explain that if my life depended on it. Lastly - anything that happens while you're busy time traveling already had a finite chance of happening anyways. Therefore, because of fancy science magic, a particle or group of particles could not go back into time and destroy itself. Whew!

Thanks, fancy science magics! If you want to read the entire paper, you can do so here.

Source: PopSci


Comments on