It was curiously fitting to find In Our Time contemplating the end of the world as we know it. It's all too easy, gazing round the broadcasting landscape and chancing on programmes like F*** Off I'm Fat, or Snog, Marry, Avoid?, to get an inkling of cultural apocalypse. But if there was ever a programme to be put in a time capsule to prove that alongside the deluge of drivel with which we divert ourselves there was something that justified millennia of brain evolution, then it's In Our Time. I don't think this is over the top, is it?
Anyway, it's the 500th programme today, which no one anticipated when Melvyn Bragg was handed the format after being sacked from Start the Week in a woeful spasm of BBC internal politics. Last week, the subject in question was the age of the universe and the pundits were Sir Martin Rees, the Astronomer Royal, Carlos Frenk and Carolin Crawford. Now no sooner have I come out with my ecomium, than I have to admit this was a tougher listen that normal. Perhaps it is to do with the very abstract nature of cosmology. What you need to know is that the current estimate of the universe's age is 13.7 billion years, and that it's still expanding. There was a neat description of how Newton concluded the universe was infinite because in his theory of gravity matter attracts other matter, thus if there were a finite number of stars they would all have ended up in a great big lump. There was also a consensus that the Sun has only another six billion years to go. Yet the way Martin Rees put it, the end of the world sounded bleakly beautiful. "The best guess is that the universe will go on expanding for ever and that it will become ever colder and ever emptier."
Somehow, even when you grasp only one idea in 10, you still come away enriched. At its best, In Our Time is like some university of the airwaves where you can pick and choose from quantum physics, medieval philosophy, Egyptology, random numbers and Foxe's Book of Martyrs. At its worst, panellists waffle or jargonise, or employ the historical present or are snapped at by Melvyn, though aficionados enjoy that. The key is in the diversity, amply exemplified by the spring schedule, which includes the "Bhagavad Gita", the neutrino and "Cogito ergo sum". Today's programme is on free will and long may Melvyn enjoy that at the BBC.
Another radio host who deserves credit for versatility is 5 Live's Richard Bacon. Whatever the collective noun for radio studio guests – a conflagration? a congratulation? – it frequently applies to Bacon's lively show and last Thursday there was the enjoyable juxtaposition of Sarah Brown and Peter Mandelson book flogging. Sarah came first, sounding not so much a guest as someone handcuffed to a chair after a period of extraordinary rendition. Her voice was high and unrelaxed but she didn't break. "Gordon is a kind person who is concerned and caring about other people," she insisted. One of Bacon's skills is to perform a good cop/bad cop routine all by himself. So what was the lowest point in office? he asked caringly. Sarah couldn't think of one. "What about this?" he suggested, triggering a clip of Bigot-gate, which by now Sarah Brown must have engraved on her heart. One can only hope she managed to avoid Peter Mandelson, who bounded in like Tigger on Prozac and proceeded to spill the beans on Gordon's caring nature. Gordon won't speak to him any more, he confided. "Did you ever tell Gordon to say sorry?" asked Bacon. "Yes." "Did he take your advice?" "No." From that, Bacon moved on to an item about removing a dog's anal glands. As I said, he is nothing if not versatile.