In these times of media whoredom and widespread desperation for fame, even of the most fleeting variety, it may come as a surprise to some to discover the world simply doesn't revolve around them. No siree - as our beautiful planet continues to orbit the sun, you and I are as insignificant as the dirt on the bottom of our shoes. Sure, every little thing we do has a minor impact on the environment around us, but when we stop to consider the stunning dynamism of this vast world we live in, how can anyone continue to care about which D-list movie star is dating which pointless pop "artist".

Orbit: Earth's Extraordinary Journey (BBC Knowledge, Tuesday at 9.50pm) is a three-part documentary that reminds us all how small we really are. Co-presented by wildlife expert Kate Humble (pictured; The Spice Trail) and physicist Dr Helen Czerski, whose pockets are clearly burdened with huge travel budgets, Orbit both dumbs down and sexes up the science behind our planet's journey around the sun. If you paid any attention in science class and didn't just cook anything within arm's reach of a bunsen burner, then you may find it all a bit oversimplified, but to the average thicko in the street (me) it is informative and entertaining without having to rely on complexities. Conducting hands-on experiments and using flash computer graphics, Humble and Czerski skip across the globe visiting a bucket list of idyllic locations (somewhat needlessly, you might argue, except it's all visually stunning) to demonstrate how hurricanes, deserts, tides and the Coriolis effect are all governed by the planet's rotational force. Who knows, if science had been this sexy at school I might not have had to write television reviews for a living.

As a tonic to all the brain gymnastics, though, it's a pleasure to occasionally kick back and switch off with a relaxing brew of light comedy. The Cafe (BBC Entertainment, Saturday at 6pm) is a sweet and sugary comedy drama from the school of "less is more". Written by and starring Michelle Terry and Ralf Little and directed by Craig Cash (who co-wrote The Royle Family and starred in it alongside Little), it is set in and around a struggling British seaside "caff" run by a grandmother, mother and daughter.

A selection of cheerful everyday folk pop in and out and, as with the living room in The Royle Family and the pub in Cash's Early Doors, the easy humour comes from people just sitting around and talking about nothing in particular. With only a faint plot and devoid of any obvious punchlines, The Cafe embraces the tedium of everyday life and serves up a generous slice of nostalgia for the heyday of British holiday resorts. It is not about belly laughs - this show succeeds by raising titters and wry smiles. The West Country accents only serve to emphasise the warm intentions and subtle scripting ("Wendy's daughter's a lesbian and she's done ever so well") that make The Cafe an honest and enjoyable portrayal of a sleepy coastal town.

Looking at a very different side of life is retired no-nonsense Lieutenant Joe Kenda in Homicide Hunter (Fox Crime, tomorrow at 10.50pm). The straight-talking former detective of Colorado Springs Police Department, in the United States, and narrator of this unique true-crime show, is a master at solving murders. With a staggering 400 convictions under his belt, the show's producers had the sense to let the deadpan Kenda just sit there and do the talking, and he's a captivating storyteller.

Focusing on a different investigation each week, with case reconstructions and interviews with key figures, Homicide Hunter also reveals the emotional and psychological marks that a murder can leave on the investigator.

Strangely, with such forensic expertise in evidence, the only disturbing unsolved crime is how our seasoned detective thinks he can get away with such a remarkable rug on his head.