There's a very interesting thread on Quora, in which people of varying backgrounds are discussing time travel. Specifically, they're addressing a pretty good question: Why are people from the future not time traveling to our period?
There is a lot of good discussion about it - 32 answers, to be exact, but I found it particularly interesting that a couple of Facebook engineers took on the topic.
"If time travel were to exist, it may depend on forking the universe so that time continues separately down two paths with and without the time traveler's disruption," writes Facebook engineer Tom Whitnah. "If that's the case we may exist on a series of forks that were never disrupted by a time traveler, but parallel universes exist where 'we' have confirmed interactions with future dwellers. Maybe eventually the version of you asking this question will experience a future dweller in the fork in the universe 'you' experience."
Facebook software engineer Liz Zhang also weighs in: "If you think conservation of energy + mass is true, and time is just another dimension you can move within, there should be nothing left in the past once you (and the world) proceeded into the future. Otherwise, you have the contradiction that by travelling back in time, you can arbitrarily increase the amount of mass & energy exist in the world. So I guess you might be able to travel back in time, but you will see nothing (empty, ether, null) there, because we have moved on."
OK, a couple of software guys who happen to work at Facebook simply talking about time travel doesn't exactly mean Facebook will be inventing a time machine. That said, before Google's IPO, there probably weren't many expecting the company to launch driverless cars, futuristic augmented reality glasses or be involved in the mining of asteroids either.
At least we know that Facebook does have engineers who are thinking about time travel, even if they're all optimistic about the concept. We also know that the company hasn't been shy about hiring away Google engineers.
It could make Facebook Timelines a lot more interesting. Currently, Facebook will let you go back to 1000 A.D.
Of course, Quora users were more interested in about ten other answers. The Facebook engineers' posts only got 4 upvotes each. The top one, which comes (interestingly enough) from a former Facebooker - current Reddit CEO Yishan Wong - suggests that the time we're living in just isn't interesting enough for time travelers to frequent, compared to many of our planet's other eras.
Hat tip to MG Siegler for pointing out the Quora thread in a Tumblr link.