It's been quite a while since we've had a proper, big-budget piece of speculative biology or xenobiology on TV, so I was definitely hyped to find out about Alien Worlds. Following in the footsteps of prior attempts like The Future is Wild, Alien Worlds is presented as a standard nature documentary, only with a focus on a different exoplanet (and therefore a completely alien – in every sense – ecosystem) for each episode. The actual "nature footage" is all CGI, but the team behind the creature designs hold some serious credentials between them, so this is definitely true spec-bio, based on the scientific process and real-world biological theory. Think of it as a scientific thought experiment given state-of-the-art visuals.

Understandably, that reliance on CGI is a bit of a stretch for a TV series, so the show spends about 60% of each episode back on Earth talking to specialists in relevant scientific fields (as well as routinely reusing pieces of footage between segments). For the most part, these cut-aways are well presented and help contextualise the evolutionary processes and natural phenomena that are being used to justify the creature design and "alien" behaviour. They're also a wonderfully diverse range of perspectives, with the makers of the show seemingly having gone out of their way to highlight a variety of specialities and voices. For once, it's not just all white dudes in white lab coats! We get field researchers from all manner of cultural and racial backgrounds, people working in theoretical fields, and even get a behind-the-scenes look at how real nature documentaries are filmed themselves. Honestly, it's quite a refreshing experience! (except for in the final episode, which is white men to the horizon)

On the other hand, the actual science being covered rarely dips below the level of lowest-common-denominator. The series highlights wide-ranging evolutionary science and does a good job of breaking down complex subjects, but if you have any prior education in the field you won't be learning anything new. I understand the need to make this accessible content and, ultimately, the role of this kind of programme is to hook people in with fantastical imagery and trick them into gaining a better understanding of the underlying research and processes, but it's a shame that there isn't anything a little more advanced scattered in. After all, whilst mainstream buzz is the aim, the most loyal and immediate fans are going to be those already exposed to spec-bio or similar fields, and there isn't much for them. In fact, in the final episode I'd go so far as to say the science is just a bit weird. You have an alien race with the ability to develop solar batteries, but which can't move planets? Or which don't time their rocket launches to use their original homeworld as a solar-wind shield? The concept is cool, but it feels like there would be better solutions at that level of technological advancement.

I guess the counter-argument to the over-simplification here is that people like me will stay for the creature design, and to that end, I think the show is largely triumphant. Rather than simply rehashing common ideas or creating obvious alien monstrosities, the planets we "visit" are diverse and provide some genuinely interesting xenobiological possibilities. The first episode, for example, focuses on a high-gravity super-Earth, which means ballont-style gas-filled organisms aplenty. Luckily, though, the animals aren't just one-off "what-ifs" but instead placed in a wider ecosystem, letting us see how a semi-complete food chain: planktonic, photosynthesising airborne seeds; giant "sky grazers" that spend their lives on the "wing" in the dense atmosphere; ballont-like aerial predators that hover in wait and divebomb their prey; land-based predatory scavenger "blobs" that lack a clear skeleton due to the high gravity. The following three episodes then cover (respectively) a tidally-locked world of radially-symmetrical, highly adaptive arthropod-analogues; a world of ideal conditions with a binary star, creating some interesting evolutionary forces and seasonal migrations; and a world at the end of its life, colonised by a hyper-intelligent alien race. Many of these evolutionary tactics and ideas have been explored before in spec-bio works, but there are still a few surprises and novel concepts, and it's a lot of fun to see the whole narrative piece together in full CGI glory.

Oh, and worth noting is that one of the consultants on the project has a full review and some behind-the-scenes details on how they came up with the various alien species themselves: TetZoo: Alien Worlds.