Maybe I’ve been watching too much Doctor Who lately.
Many of my friends asked me about the faster-than-light neutrino announcement from CERN. I must say I am skeptical. One reason why I am skeptical is that no faster-than-light effect was observed in the case of supernova 1987A, which exploded in the Large Magellanic Cloud some 170,000 light years from here. Had there been such an effect of the magnitude supposedly observed at CERN, neutrinos from this supernova would have arrived years before visible light, but that was not the case. Yes, there are ways to explain away this (the neutrinos in question have rather different energy levels) but these explanations are not necessarily very convincing.
Another reason, however, is that faster-than-light neutrinos would be eminently usable in a technological sense; if it is possible to emit and observe them, it is almost trivial to build a machine that sends a signal in a closed timelike loop, effectively allowing us to send information from the future to the present. In other words, future me should be able to send present me a signal, preferably with the blueprints for the time machine of course (why do all that hard work if I can get the blueprints from future me for free?) So, I said, if faster-than-light neutrinos exist, then future me should contact present me in three…, two…, one…, now! Hmmm… no contact. No faster-than-light neutrinos, then.
But that’s when I suddenly remembered an uncanny occurrence that happened to me just hours earlier, yesterday morning. We ran out of bread, and we were also out of the little mandarin or clementine oranges that I like to have with my breakfast. So I took a walk, visiting our favorite Portuguese bakery on Nelson street, with a detour to the nearby Loblaws supermarket. On my way, I walked across a small parking lot, where I suddenly spotted something: a mandarin orange on the ground. I picked it up… it seemed fresh and completely undamaged. Precisely what I was going out for. Was it just a coincidence? Or perhaps future me was trying to send a subtle signal to present me about the feasibility of time machines?
If it’s the latter, maybe future me watched too much Doctor Who, too. Next time, just send those blueprints.