"Remember time cadets, the only way to communicate in those days was something called a 'social network'..."

Today 'the social network' is how 'space cadets' communicate.

I think the IgNoble Prize is only for projects that spend a lot of money or claim success. As to "forbidden by current physics", let's begin by consideration of Conservation of Mass/Energy. The sudden appearance of a mass at THIS time is NOT balanced by the (anticipated) vanishing of a similar mass at a future time.

With apologies to Steven Jay Gould, when it comes to time travel from the future, absence of evidence IS absence of evidence. It is inconceivable that time travel will one day be possible yet no one from the future has sought glory by providing ready, incontrovertible proof. Unless, perhaps, people will be able to travel back in time for only a few years or decades.

@piperTom, it's far more complicated than that...suffice it to say while it seems incredibly unlikely to have happened, it's simply not true that time travel must violate CME;
frankly, I'm much more worried about the fact that we're almost certainly a simulation universe than I am about where the time travelers are...

I think that moving from the future into the past is not possible. One might, however be able to move into a similar past. In other words you cannot go back and kill your grandfather.

Aside from the known physics (that THAT can stir some controversy :-) ), it seems there can be no way to actually "catch" said time traveler, except by their intention or mistake, EITHER OF WHICH could easily be undone. Even a discovery of said mistake could be undone.
We can never know.

Remember this? http://www.rense.com/general36/time.htm 'Time-Traveler' Busted For Insider Trading - "We don't believe this guy's story -- he's either a lunatic or a pathological liar," says an SEC insider. "But the fact is, with an initial investment of only $800, in two weeks' time he had a portfolio valued at over $350 million. Every trade he made capitalized on unexpected business developments, which simply can't be pure luck."

If there are no time travelers, maybe we succeeded in annihilating our species before the technology was discovered.

Or perhaps traveling to the past invariably causes a tangent universe that we are no longer a part of?