Slartibartfast would probably know

I am having trouble with measurements. I probably shouldn't think about these things too much but this has been on my mind for a while now. It's this business of how long something is. So the distance between some marks on my ruler is an inch or a centimetre - that's OK, I can cope with that for now. It all started with maps.

I looked at a map of the British Isles and wondered how long the coastline was - the bit around the mainland. It could have been any island - just happened to be the one I live on.

I used to have one of those smart wheel things that you could roll around a line and it would tell you how long it was. That would have been useful. A piece of string would be useful too. But there are quite a few wiggly bits. Not as bad as Norway, of course, but pretty bad none the less.

Walking around the coast with some gadget or other would provide an answer. But that misses out quite a few little ins and outs. Even if I could go around each of the little ins and outs, how far should I go up a river? OK, there could be a rule for that - up to the first crossing.

This gets tricky, though - not the rivers, I am reasonably content about them - the fiddly bits like rocks, stones, pebbles, small pebbles, tiny pebbles. Lumps on pebbles. Even if they all stayed in the same place and even if I could measure around them. The more 'accurate' I try to be, the higher the perimeter becomes. It's not the satisfying outcome of a figure that homes in towards something - these measurements just get wildly bigger and bigger the closer you get to what it is you're measuring.

I had hoped that you could have a triangle (or some other polygon that you know how to work out a perimeter for) that sort of fitted inside our national perimeter and then another that sat just outside it. Logically one would jump to the conclusion that the length we want would be somewhere between the two but no. the damn line in the margin between them wiggles around and gets even longer the longer you think about it.

There, something like that would have been nice. The answer would have been somewhere between the two. But no - all those wiggles cause so many problems.

Here's another example. A line looks simple and straight. But look closer and you see it has a bump. Look even closer and it has bumps on the bumps. Travel along the first line - say 3 units.

Travel along the second one and, if the bumps are even and a third of the line length, you'll go 5 units.

Go along the next iteration and you've got 25 bits, each say a third of the previous one, so you go 8.33 units.

I am guessing but I expect this just keeps rising rather than heading for some pleasant and mutually agreed figure. With even bumps like this it's all nice and fractal so there'll be a formula too. That would be nice to know if anyone cares to share it or I suppose I can work it out.

All this tells me, though, is that it is not possible to be very sure about how far it is along things. The numbers seem to get bigger and bigger. And yet we know that the Earth is only so big so there has to be a limit somewhere or we'd be talking about things that fall off the edge or make rockets redundant for Moon visits.

Am I missing something terribly obvious or is this measurement business just some convenient approximation we make in this Age and will one day be looked upon as a bit silly.

To Our Children's Children's Children

There has been talk for years about 'messages from outer space'. They've been at the heart of many a science fiction plot and, reasonably enough, are a natural extension of a belief that somewhere out there is life that has evolved to the point where those other 'beings' ask themselves the same question as we have been asking: "Is there anyone else out there?"

We've been sending messages out into the universe for thousands of years - initially without realising it and more recently deliberately with a view to showing any potential recipients the stage to which we ourselves have evolved. The changes to our atmosphere, energy emissions, land use and unnatural shapes formed are just a few would have indicated that there is someone on Planet Earth, or whatever name our world is given, alive and well and living here. If our alien observers missed those then some of our more focused efforts may have, or might one day, get noticed.

Until today, though, I hadn't been aware of our actually having received any messages. Yes, there have been rumours galore but no-one with any official standing has confirmed that we might have done in any public arena. So I was astonished to read a post on Google+ from someone called Daryl Kuzyk referring to a release by the National Security Agency titled Key To The Extraterrestrial Messages and written by Dr Howard Campaigne, a mathematician and cryptology specialist who has been working in the field of interpreting code since the Second World War and who seems to be someone who talks sense, even if it is pretty complicated sense.

It appears that Key To The Extraterrestrial Messages was published in 2004 but was only actually made public after a request under Freedom Of Information legislation in April this year. Quite why this did not make big news or, at least, appear on my radar screen, a few months ago I don't know. It may be simply because the article itself is not easy reading and, of course, the very fact that it has been released and is Unclassified tends to diminish its importance in the eyes of those who might have been inclined to tell the world about it, being more impressed, perhaps, by articles or recordings smuggled out of meetings and documents with Top Secret stamped all over them, especially those with black rectangle redaction on every page.

Or it could just be this, NSA telling us: "OK, folks, we have had something that appears to be communication from somewhere other than Planet Earth. It might be something someone here has sent out that has found its way back to us but our experts reckon it is from an alien source. Not much more we can say, really. Our chap Campaigne has done his best to make some sense of it and we've published what he says for those of you who have trouble sleeping at night to read. No big deal. No green monsters about to invade. No chance of seeing anyone or any thing in our lifetimes or, for that matter, in our children's children's children's lifetimes either so here you are, have a look."

If you're interested, here's the document itself and an article about it in more detail.