Last Night's TV - Everything and Nothing, BBC4; The Secret War on Terror, BBC2

Science lesson's out of this world

It's always the biggest somebodies who are best able to make us understand that we're a planet of nobodies. This, I think, might even be a paradox that nobody has alighted on before, one I'll call Viner's Theorem, and its latest embodiment is the splendid Jim Al-Khalili, who kicked off his documentary, Everything and Nothing, with a statistic so mind-boggling that my wife refused to believe it.

There are more stars in the galaxy, he said, than there are grains of sand on every beach in the world combined. "Surely that can't be right," muttered my wife, refusing to withdraw her scepticism even when I gently pointed out that Jim Al-Khalili is professor of physics at the University of Surrey and a world-renowned authority on mathematical models of exotic atomic nuclei, while she develops a twitch at the sight of a Van de Graaff generator and had to be helped out of a classroom, while visiting our children's prospective secondary school some years ago, after spotting a periodic table.

Happily, I empathised with her that day. The chemistry between us owes just a little to our mutual teenage ineptitude in the sciences. In fact, I fared even worse than she did in my science O-levels, not even scraping in physics the F I managed in chemistry. Instead, I was handed a U, standing for unclassified, which at least gave me, with my astounding C in Biology, a rather satisfying run of letters on my certificate.

Anyway, the point is that in the subsequent 33 years I've always been playing catch-up, struggling to understand even the most basic of scientific theories. You will appreciate, therefore, the apprehension with which I settled down to watch Everything and Nothing. And yet, such is Al-Khalili's soothing tone and considered use of language that he carried me with him pretty much all the way, beginning to lose me only when he got to non-Euclidean geometry, and finally casting me off into the black hole of complete bewilderment with his assertion, apparently something to do with the Big Bang 13.7 billion years ago, that one per cent of television static is "the afterglow of creation itself".

What had already hooked me, though, was his foray through the ages. I've always loved history, and it turns out that the history of clever people trying to understand the universe is particularly fascinating, with a notable 16th-century champion in the form of Thomas Digges, the MP for Wallingford.

These days, of course, Wallingford is best known as the thinly disguised location of Midsomer Murders, the place where to be involved in a murder as killer, victim, policeman or passer-by, you have to be of lily-white, preferably Anglo-Saxon stock. But it was Digges who put the town on the map, with his own map of the cosmos. As I understood it, which as you'll know by now is not necessarily the same as how others understood it, Digges updated and in so doing undermined some of the theories of the celebrated astronomer Copernicus, by showing that stars exist in infinite space. That seems to have been the pattern throughout the centuries. A brilliant scientist makes a discovery, aspects of which are disproved 50 or 100 years later by another brilliant scientist.

Whatever, it's probably safe to say that I learnt more in an hour listening to Al-Khalili than I did in four years with assorted science teachers, and underpinning it all were his brief but beguiling portraits of great cosmic ponderers, including the American astronomer Edwin Hubble, a keen Anglophile who liked to stride around his observatory exclaiming "By Jove!" and "What ho!" Al-Khalili is one of those cherishable scientists who understand that people make the world tick no less than particles.

Sometimes, though, it's the wrong kind of ticking, as they know all too well in the city in which Al-Khalili grew up, Baghdad. In The Secret War on Terror, Peter Taylor took up where he left off last week, examining the successes, but also the failures, of the US-led campaign against al-Qa'ida and its offshoots since 9/11.

Now, it might seem decidedly provincial of me, but the best way I can make sense in my own mind of the so-called war on terror is to liken it to our efforts in rural Herefordshire to keep our flock of chickens safe from predators. Every morning for five years we let our chickens out of their pen to free-range in our little orchard, and every evening we locked them up. One night, we forgot to lock them up; the next morning they were fine. So gradually we relaxed our vigilance until, 18 months or so later, a fox killed all of them. Now we're super-vigilant again, but that's no use to the 13 hens who were decapitated, and whose bloody demise proved the sense of what a wise old countryman had told us when we first acquired poultry. "The fox only has to get lucky once," he said, "but you have to be lucky every time." Thus it is with al-Qa'ida and the West.

Taylor's talking heads, however, didn't need to peck around for such analogies. It was a coup for Taylor to extract a rare TV interview from the former head of MI5, Baroness Manningham-Buller, and she rewarded him both in last week's programme and again last night with a series of perceptive insights that made me a little regretful that she's not still top dog. She also pointed out that the only place on Earth where al-Qa'ida is assumed to have no presence is Antarctica; the very definition of a chilling observation.