THERE are more things in heaven and earth, correct me if I'm wrong, than are dreamt of in your philosophy. In an edition of the science programme Frontiers, entitled "Some of Our Universe Is Missing" (Radio 4, Wednesday), the tag turned out to have a gratifyingly literal application.

Peter Evans talked to a number of scientists about "dark matter", the really heavy, black stuff which, according to the best calculations, is floating around, invisibly, somewhere in the universe.

The argument goes like this: it seems clear that there must be an awful lot of gravity holding the whirling cosmos together. And since gravity goes along with mass, we can have a pretty good stab at the mass of the universe. But when we compare that calculation with the amount of stuff we can see, it seems that we can only account for about 10 per cent of that mass. So there must be vast quantities of invisible stuff to make up the difference.

This opening section was presented with admirable clarity; after that, though, despite his best efforts and those of the scientists interviewed, clarity broke down somewhat. This is not an area in which clarity is entirely possible.

The fascinating part of the programme came at the end, where scientists suggested alternatives to dark matter: perhaps we're wrong to assume that space is a simple, empty thing, and the effects we attribute to dark matter are just space doing what it does. Or perhaps we need to scrap all our physics and begin again from first principles.

Most scientists, understandably, were unhappy with this idea, but one or two were tickled. That line about more things on heaven and earth is a cliche beloved of the X-Files fan, but really, it is science's own motto - an acknowledgement that it doesn't know all the answers and shouldn't claim to.

In the same week, however, we have had a depressing example of the thoroughly unscientific, in the shape of Sleuths (Radio 4, Tuesday). This series ended with a look at Keith Wright, a detective with the Metropolitan Police who moonlights as a clairvoyant. Wright, himself, had no time for scientific justifications, he just "knew" that his psychic powers worked, and backed his knowledge up with some vague anecdotal evidence.

More worrying, though, was the thoroughly uncritical tone of the programme, taking all his claims at face value and giving him airtime to counter every attack. What is the point of broadcasting science programmes when you undermine them with superstitious tosh?