Matter Displacement Detector, ahoy!

A few days back, I happened to watch a few scenes of an old Star Trek episode. There was the usual fare of beam-me-ups, tea materializer, mother levitator, etc. And then there was the Matter Displacement Detector. That piqued my interest. This device allows the Star Trek crew to check if there was someone at a place in the past. Presumably, the said person left eddies in the spacetime continuum that can be detected to ascertain the presence of the person in question. Naturally, I started wondering if the physics behind it is plausible in some way. It was not explained in the episode, so we can only speculate picking our clues from the almost childlike imagination of Star Trek creators (I say childlike in both the good and the bad sense: good when it pushes the envelope on what we think is possible, bad when it exhibits astonishing level of scientific ignorance).

So, what could possibly be a Matter Displacement Detector. Linguistic analysis tells us that it is a device with which we can detect if the cheese was moved by analyzing molecular movement (don't they have this at hotel room fridges already?). It is clear that detection in Star Trek's case is not by way of chemical analysis of leftovers, but by detecting the displacement of matter. That, to put it charitably, is bollocks. Unless - oh, dare I say -, unless, Star Trek crew was using a whole new kind of scientific knowledge, whereby they can routinely solve many-body problems for small masses like molecules. A many-body what?

A many-body problem. This is an appropriate name in physics for the problem where you try to figure out the past (or future) location of, say, the red ball on the snooker table by working out all the collisions it had (will have) with other balls. This is essentially an impossible problem to solve as time goes by (think Butterfly effect, Statistical methods were invented precisely for this reason when physicists realized one cannot figure out stuff about gases by working out what individual molecules do).

If we suspend disbelief and accept that Star Trek crew do indeed have little gadgets that solve such apparently intractable problems - given all that Star Trek crew do, this is a small thing to ask -, then, hey, Matter Displacement Detector is a fine thing. I don't want to give an impression that I am put off by Star Trek, quite the contrary. Evidently, I find it engaging. Star Trek has helped nudge many, especially kids, to take interest in science. This is a good thing (except, when it is not).

That said, if modern crime scene investigation is any indication, we have got pretty good at detecting traces of someone at a place. We are made of watery goo and much of it leaks from us all the time leaving our slimy traces everywhere we go. If the Star Trek crew had opted for straightforward forensic analysis, I suppose they would have more success in their investigation (obviously, the producers of the show may not have succeeded in their investment, which lies at the heart of why Star Trek crew do things the way they do).

Enough. Here's a fine story from COSMOS magazine I ran into while researching (heh) for this blog post.

I hope to see the new Star Trek movie this weekend. Hear good things about it.