All these are interesting pieces of information, many of them changing in interesting ways, telling me something about my journey, something that somebody on board might wish to know. But now, what have we here? “Outside temperature -58°F (-50°C)” – and we are told the same thing in Spanish, for good measure. Why on Earth should I, or anyone on board, want to know that? Obviously, at this altitude, it is bound to be very cold out there, but what difference does it make to anything that matters? If the window out of which I am looking should chance to shatter and I be sucked out, it perhaps advises me whether I would die of cold before I die of oxygen starvation or of hitting the ground, but in reality? Is this number posted on the little screen in front of me purely because it is easy to measure, so it might as well be there?
It reminds me of a schoolmaster of my acquaintance (and, I have heard, an exceptionally good science teacher) who loves measuring everything. He used to take parties of boys on cycling trips and he would print out on his computer minute details of the trip before setting off. Meticulously tabulated, and distributed to all his friends and relations, would be the mean ages, heights and weights of all the boys in the party, complete with standard deviations, the estimated time of arrival at each youth hostel on the way and many other such minutiae. If something can be measured, you might as well measure it. And, in his case, since the computer is capable of computing the standard deviations of all the measures, why not let it have the fun of computing them?
Unless you happen to be a brass monkey clinging for dear life to one of the wings, why should you want to know the temperature outside the plane in which we are trying to while away the long hours? Yet every plane I can remember, which has a moving map at all, scrupulously tells us the outside temperature. I can’t help thinking of all the other things that could be measured, which might be more interesting. If we must have temperature, how about temperature at our destination? Or the pollen count? Or the temperature on the ground over which we are flying, so we can picture the people down there: in their bikinis or their fur-lined parkas. How about our present latitude and longitude? The compass direction in which we are heading? The pitch, roll and yaw of our craft? I’d quite like to know the altitude of the ground below us above sea level. Or our height above the ground we are flying over (which was interestingly a lot smaller when we were crossing the Rockies than it is now). Why not tell us which tectonic plate we are flying over? How many cosmic ray particles are raining down on our heads? How about – to really stretch things – the Captain’s pulse rate, which might tell us something about how anxious he is? Even if his pulse rate is as rock steady as we might hope, it is surely more likely to be relevant to something important than the outside temperature.
The Moving Map of the future, as I see it in my imagination, will show key points from the Wikipedia (or whatever Wikipedia has evolved into by then) entry for whatever we are flying over. If it’s a town, the population and principle industries of the town. If it’s a geological feature such as a mountain range or a series of glacial valleys, something about the upheavals or other geological phenomena that engendered it. Perhaps something about the wildlife that we might see if only we had telescopic eyes – well, you get the idea: use the fact that we are moving over the face of the globe to educate the curious passenger in exactly what is unique about this particular spot the she is visiting now for the first, and very probably last time.
But the outside temperature? Cool your jets, who cares?