Last Night's TV: Wallace and Gromit's World of Invention/BBC1<br />Horizon: Asteroids &ndash; the Good, the Bad and the Ugly/BBC2

I don't mean to be harsh, but I think Wallace's future as a television presenter is limited, despite the fact that he appears to have his own television studio in the basement. It isn't just that he has a face for radio – with his chiclet teeth and his permanently astonished gaze – but there's also the question of his reaction times. He can appear spontaneous, it's true, but it takes a team of three people working for a fortnight to make him so, which is always going to make things tricky when it comes to topical content. Hardly surprising, then, that in Wallace and Gromit's World of Invention he's only supplying fairly minimal links to filmed reports – heavy on the bad puns and relatively light on the elaborate ingenuity which fans have come to associate with one of Aardman's leading stars. If you were hoping for 30 minutes of animation you will have been disappointed, because Wallace and Gromit are here only as a kind of novelty wrapping paper for the sort of technological curiosity that would have once filled out the lighter stretches of Tomorrow's World.

This wasn't a programme for devout creationists, I'm glad to say, emphasising the design genius of Mother Nature – an engineer who takes almost as long over her creations as a Claymation animator. She'd been perfecting her designs, we were told, for about "four billion years", so it's understandable that some of them are worth plagiarising; and while Mother Nature is good at product design, she's absolutely lousy at filing for copyright protection. The first film featured a German firm, which had borrowed the structure of a manta ray's wing to produce a radio-controlled helium balloon that could fly itself round the room, an object which not only looked almost as captivating as the real thing, but also provided Wallace with the cue for a cheesy back-announce. "Ahhh... that all went swimmingly anyway," he said – by no means the corniest of the gags he deployed.

There was a bit of comic business in the studio, aimed, like most of the rest of the programme, at a fairly young demographic. This week it involved Wallace's personal contribution to eco-engineering, an electricity generator built around an elephant called Kevin, which took in brussels sprouts at one end and emitted usable methane gas at the other. "That's wind power for you," chuckled Wallace, before introducing an item about an eccentric Dutch sculptor/inventor who's spent years creating giant, self-propelling biomorphic insects out of PVC electrical ducting, with each evolutionary generation adding new refinements, including energy storage and a primitive sensory apparatus that allowed them to retreat from water. If they have water coolers in playgrounds these days, this was definitely the kind of thing that would generate a bit of buzz around them at breaktime – even if an older viewer might regret that its inherent freight of evolutionary ideas hadn't been a little more explicitly unpacked. Overall though, the programme is charming – its fart-flavoured sugar coating a good match to content that looks as if it should pique youthful scientific curiosity.

The good news in Horizon's film about asteroids is that none of the really big ones are likely to hit Earth in the next 100 years. The bad news is that there are nearly a million smaller ones floating around up there that could potentially give us a very bad day – and spotting one of those is like trying to pick out a charcoal briquette in an unlit coal cellar. One actually hit the Earth in 2008 after what must have been an unusually galvanising day at the office for the scientists who spend their time tracking these things, who had discovered that however many times they did their sums, they kept predicting an imminent collision. They got their sums right, but fortunately it landed in a very remote part of the Nubian desert rather than the middle of Soho. The other bit of bad news is that the small asteroids do much more damage than people had previously assumed, because Jupiter's gravitational slingshot field pelts them at us at around 12 kilometres a second, a speed which means that they announce their arrival with an incandescent blast field that does more damage than the rock itself.

You can't really begrudge the asteroid hunters their moment of sci-fi glory, which included ringing up the powers that be in Washington to warn them that the very big explosion that was about to go off wasn't a rogue nuclear weapon. They surely earned themselves a bit of excitement because the day-to-day business of asteroid tracking seems to be big on grind and small on gratification. Fortunately, perhaps, there are enough men who find the enigmas of the solar system's building rubble completely entrancing – and who are happy to devote every day to learning more about them. Horizon's film included the scientists who'd discovered that the reason they keep flying at us is because they're knocked out of stable orbits by the weight of the sunlight falling upon them (sort of); the men who argue that they may have supplied Earth with all its water; and a cheerful chap who was convinced that they'd delivered the building blocks of life itself. And best of all, not one of them had to submit themselves to the lame jocularity of Alan Davies – or some other mid-list celebrity comedian – before they were allowed to share their enthusiasm.

t.sutcliffe@independent.co.uk