TV review: Horizon: Seeing Stars

Christian, in John Bunyan's The Pilgrim's Progress, is able to look at the Gates of the Celestial City through a telescope, or a "Perspective Glass" as it is called in the most famous allegory in English literature. Technology has come a long way since Hans Lippershey first aligned two lenses to bring a distant object into closer view (Horizon: Seeing Stars, BBC Two, Monday 15 August, 9pm). We are still examining the heavens, but they look very different from how Christian saw them: then, they shone and shimmered; now, it is their darkness that dazzles.

High in the mountains in Chile's Atacama Desert are several, rather literally named, Very Large Telescopes (VLTs). They search not for God but for black holes - the scientific equivalent of Goya's Saturn Devouring his Children. The gravity of these gargantuan distortions of space-time means that not even light escapes their crunching bite. They do, though, burp out radiation on the infrared scale. Normally, moisture in the atmosphere makes the signals difficult to detect, but the VLTs have no trouble picking them up in the dry desert air.

The physics of black holes continues to be a matter of dispute. Stephen Hawking's equation for the entropy of black holes maintains that whatever they gulp down is lost for ever. But this violates the law of unitarity, which states that while an object can vanish, the information it contains cannot. If that happens then knowledge of the past disappears and we cannot predict the future. Of course, this is the normal state of affairs in the humanities, but you can see why it might dampen a physicist's mood.

If there's something strange in your Universe, who you gonna call? Leonard Susskind, that's who. He showed that as, say, David Cameron approaches the black hole's event horizon, he gets turned into a two-dimensional image, although some may say he is that already. Others, less generous, would say that he is not even that substantial. Be that as it may, the prime minister, or whatever wave-functions are responsible for his quiff, is saved; although not in the Bunyanesque sense of the term.

The idea that it is the fate of the cosmos to become an image of itself has parallels with Baudrillard's theory of simulation. Which should put an end to all that nonsense about there being two cultures and never the twain shall meet. And lo the wolf shall dwell with the lamb and the physicist shall lie down with the social theorist. Having healed that divide, mending broken Britain should be a doddle.

Back in the Atacama, the talk was of who drank the most coffee. A caffeine drip is essential if you are to remain alert while watching the cosmos revolve through the long night hours. Black holes were proving elusive. One astronomer, dishevelled from lack of sleep, did find an old image of this obscure object of desire. A little patch of the galaxy, 3,000 light years across, captured on an 8"x12" photo. It's the sort of compression a poet seeks: to make one little room an everywhere. The astronomer pointed to a yellow dot as the location of a black hole. This segued into a shot of the yolk of an egg as weary stargazers sat down to breakfast.

With each new advance in telescope technology, we see through a glass a little bit less darkly. A massive gas cloud in Centaurus A, a rearing tower, was photographed in normal light, infrared, X-ray and with radio waves to reveal the unbearable lightness of non-being. The James Webb space telescope, at present under construction, will go into orbit a million miles from Earth in 2018. Hubble hovers only 347 miles above the planet. Scientists are understandably excited. "The one thing we can be sure of", said one, "is that we will find things we don't expect to find." We look up at the pearled and sequinned skies, and feel insignificant, but we shouldn't. We are a species who can study the great spangling of stars and understand how we got here. And that's not insignificant. That's progress.

One person who certainly doesn't feel diminished by the scale of the Universe is Gilbert O'Sullivan (Gilbert O'Sullivan: Out on His Own, BBC Four, Friday 26 August, 8.50pm). He was miffed that the media were more interested in Billy Joel than in him. By the end of the hour, you could see why. "If someone's fat, I tell them." At one point, he talked about himself in the third person: "What's nice about Gilbert's work is his middle sections." At another, he compared himself to Irving Berlin. O'Sullivan wrote some good songs in the 1970s but, really, some stars are better seen at a distance. Close up, they can lose their shine.