The Science of Aliens, a new exhibition at the Science Museum, reveals that the answer to the perennial question “Are we alone?” may be closer than we thought. While many will be drawn to a presentation of the Daleks and androids that have fuelled the world of sci-fi, and some interesting insights into the more “alien” habitats within the Earth’s crust itself, the real meat lies in the exhibition’s third area. Taking impetus from a forthcoming Channel 4 documentary, Aliens, and working with the producer Nick Stringer, I was part of a team of scientists thrown together to brainstorm new biospheres into existence.

We imagined a world with an atmosphere much thicker than that of the Earth. How would life evolve? We can be pretty sure that there will be plants, but here on the satellite we called Blue Moon the forests are gigantic — trees a kilometre high. Swooping through the dense canopy are the stalkers, flying horrors that are vaguely wasp-like but much larger. Highly social and predatory, they hunt immense flyers, creatures that we dub the sky-whales.

The other planet we nick-name Aurelia — it is roughly Earth-sized, but orbiting a much smaller and dimmer star than our Sun. It is different in another important way: gravitational forces have locked Aurelia so that one side is permanently in sunlight, the other in perpetual and icy darkness. Life again adapts, and here we conjure up umbrella-like forests, aquatic foragers known as mudpods, and ostrich-like hunters, the gulphogs. In some ways this is a very stable world, but actually danger is never far away. From lethal predators to the star’s sudden and intense ultraviolet flares, we envisage a dynamic alien ecology.

The Science of Aliens is a thought-provoking exhibition, stretching and entertaining the minds of both children and adults. In the last section, a “communication zone” poses the question: what happens when we do make contact? Is there any way that we can we talk to them? What would we say? The search is already on, and while radio telescopes comb the skies, new strategies are being planned. Should we be looking for intense pulses of coded laser light, cosmic beacons that transmit “Good morning, Earthlings. Here is the news” — or something more sinister?

The exhibition may be a short stroll through what we already know and can guess at, but we hope it will open the portals of your imagination to distant worlds that even now may be much closer to discovery than some imagine. Cuddly or ferocious; benign or predatory; aliens that look nothing like us or biopeds that are hauntingly familiar — either way, you will never look at the night sky in quite the same way again.

The Science of Aliens is at the Science Museum, London SW7, from Oct 15 to Feb 26 (www.sciencemuseum.org.uk/aliens 0870 8704868)

Simon Conway Morris is based at the University of Cambridge. His most recent book is Life’s Solution: Inevitable Humans in a Lonely Universe (Cambridge University Press)