The Depths of 'Alien Worlds'

A large, swooping creature moves gracefully through the dense atmosphere of Atlas, its long, six-limbed body munching peacefully on floating seeds. The sky grazer, a hypothesised life form on the distant planet Atlas, is blissfully unaware it is being watched by carnivorous predators ready to attack. This is our introduction to one of four fictional exoplanets the documentary Alien Worlds explores in a four-part Netflix series.

An intriguing project that will pique the interest of any individual curious about the prospect of life elsewhere in the universe. But is the documentary as good as it sounds? Well, that depends on what you look for in a documentary. If all you want is a basic understanding of astrobiology, then this is a pretty good place to start; as for those who have taken the astrobiology module here at St Andrews, it might be a bit harder to swallow. 

Alongside the bizarre world of Atlas, we find three planets: Janus, a tidally locked planet that creates hemispheres of perpetual darkness and light; Eden, an oxygen-rich world orbiting two stars; and Terra, a rapidly dying planet with an intelligent civilisation desperately trying to escape the death of their star. On each of these planets, a comparative biological approach is used to consider how the laws of life on Earth may affect life on other planets. Atlas considers symbiotic relationships between predators and hydrogen-producing bacteria, whilst Janus delves into the eerie world of mimicry and venom. This method of storytelling provides an excellent overview of the basic science behind astrobiological research and the interdisciplinary nature of the field involving how life interacts with biotic (living) and abiotic (non-living) factors. 

Although the series demonstrates excellent CGI and a thorough discussion of the life forms presented, Alien Worlds misses crucial elements of biodiversity and ecological substance that bring imagined worlds to life. The life on these planets is cut short with explanations of why and how we have developed these fictional worlds. Although such explanations for the mechanisms behind the existence of life are useful, there should have been a separate episode, or a longer series to explore these methods and allow the worlds to really shine. 

In each episode a maximum of three alien life forms were explored, all of which (bar one) were animal-like organisms. Excluding the scavengers, the creatures may have been too familiar to those on Earth, like they could be found in some forgotten corner of the planet. In astrobiology, there is a far larger scope of possible life forms, from the single-celled to the multicellular, from what could be considered plant-like to protists and bacteria. There were many points in the series I thought were about to expand beyond the animals and into the realm of plant-like life and cells, yet each time I was disappointed. There was either no mention of these life forms, so clearly present in their world, or a few lines on their existence on Earth.

Alien Worlds makes further general assumptions about the nature of life. Episode two provides an explanation for the origin of life — describing how life could have first evolved in the hydrothermal vents of the deep ocean, with the first cells feeding off hydrogen sulphide before switching to the now more commonly used process of photosynthesis. Although hydrothermal vents are an excellent contender for areas crucial for the emergence of life, this description ignores that the origin of life was not one singular event. 

Today, biologists continue to argue what constitutes life, with divisive topics such as whether viruses can be considered living organisms still actively being discussed today. The origin of life likely involved many different environments synthesising different chemicals essential for life on Earth, which aggregated over time to gradually create recognisable life forms. It wasn’t one snapshot event that occurred in the depths of the ocean, but a much more gradual and dynamic process. This is likely to be the same on other planets, which is why such a generalising statement can be misleading to the public.

And yet, the series provides a solid foundation of the basics of astrobiology and our search for life elsewhere. For now, however, I may stick to David Attenborough and our own brilliant planet.

Illustration Credit: Lauren McAndrew