The late cosmologist Carl Sagan once proclaimed that "every one of us is, in the cosmic perspective, precious. If a human disagrees with you, let him live. In a hundred billion galaxies, you will not find another". Sagan was without doubt a very clever fella, and I'm certainly not about to question his stratospheric wisdom, so, with the cosmic odds stacked heavily in our favour, I will definitely be having a quiet word in the ear of our creator if another Miley Cyrus comes twerking our way any time soon.

A long time ago, in a galaxy far, far away - well, actually, this one, and at the beginning of the 1980s - Sagan presented a television spectacular. Cosmos: A Personal Voyage was a groundbreaking series that popularised science and became one of the most widely watched series in the world. This week, more than three decades later, we're being treated to a sequel, the 13-part Cosmos: A Space-Time Odyssey (National Geographic, Saturday at 10pm).

Taking us on this journey of infotainment is astrophysicist Neil deGrasse Tyson, as he bids to answer some of the most profound scientific questions mankind has ever pondered. From the dawn of time to the distant future, Tyson explores the outer reaches of the universe with the aid of top-grade CGI and old-school animation, darting about on a spaceship like a cool new Captain Kirk.

Director of the Hayden Planetarium at New York's American Museum of Natural History, Tyson has a voice that sounds richer than Darth Vader enthusing over a home-made tiramisu - he could read out the molecular table and make it sound as thrilling as a new Harry Potter instalment. Coupling that voice with the budget of a small Hollywood movie and the proven pedigree of the executive producers, astronomer Steven Soter and Sagan's widow, Ann Druyan, has resulted in a TV extravaganza, part educational video, part action-adventure flick.

Pull the sofa up close to your TV, switch off the lights and surf the waves of space and time, in a never-ending search for truth. As Sagan told us in the original series, "The cosmos is rich beyond measure, the total number of stars in the universe is larger than all the grains of sand on all the beaches of planet Earth." It's going to make you feel very, very small indeed.

From marvelling at Uranus to facing deadly gale force winds; Fierce Earth (above; TVB Pearl, Tuesday at 8pm) is another documentary series revelling in the wonderment of our planet and the impressive power of Mother Nature.

This week's episode, the first, explores extreme weather, in particular hurricanes, and looks at the devastation caused by these monster storms. The overly enthusiastic Fierce Earth team investigates how hurricanes are born, as they chase destructive storms across America, putting themselves in danger in the name of research.

Compared with Cosmos, and its fancy special effects, Fierce Earth looks like a school project - it is aimed at a younger audience, after all - and feels almost primitive in its childish and unnecessarily dumbed-down demonstrations. The programme certainly doesn't have the wow factor of Tyson's and, other than the terrifying real-life footage of hurricanes, it all seems a little anticlimactic.