A very special thanks to Sam Goodlet for providing the beautiful illustrations featured above and throughout the book.

"Preston’s accessible writing style, enthusiasm, and optimism succeed at informing as well as tickling readers’ imaginations." - Publishers Weekly

"A solid, absorbing background to what makes life possible." - Kirkus Reviews

"Highly recommended" - Financial Times

"Ably distilling complicated science into digestible portions, Preston’s balance of wonkiness and wide appeal is also 'just right' and suited for anyone who’s interested in the Curiosity rover’s exploits on Mars and wants to learn more." - Booklist

"Fascinating . . . It's a compelling book to read at this moment, as man-made climate change is throwing planetary systems off balance. In her brief history of the Earth, and of the other rocks that hurtle around space with us, Preston shows just how very lucky we are to live on a planet that is--for now at least--just right." - VICE

"Louisa is that rare breed - a brilliant academic who can effortlessly communicate her subject with clarity, authority and warmth to us all. A fascinating overview of what is simply the most profound and exciting story in science." - Dallas Campbell, science broadcaster and television presenter


Today we know of only a single planet that hosts life: the Earth. But across a Universe of at least 100 billion possibly habitable worlds, surely our planet isn’t the only one that is just right for life? As Goldilocks was searching for the most comfortable chair or the perfect bowl of porridge, Astrobiologists are searching for conditions throughout the Universe that are just right for life as we currently know it to exist.

With the Earth as our guide the search has begun for similar worlds sitting at the perfect distance from their Sun – within the aptly named Goldilocks Zone – that would enable them to keep water as a liquid on their surface and therefore support a thriving biosphere. The Earth is littered with carbon and pulses with energy, which combined with its flowing water allows life to exist beneath our thick protective atmosphere. In just over four billion years life on Earth has evolved from a single celled organism to upright humanoid with the capacity to understand its place in the Universe and undertake missions to other worlds searching for a biological neighbour. Humanity has sent probes to explore our planetary family and has eagerly turned its eyes to the distant exoplanets of far away solar systems, hoping to see signs of extra-terrestrial life.

What might life look like on these other worlds? It is possible to make best-guesses using facts rooted in biology, physics and chemistry, and by studying ‘extremophiles’ on the Earth, organisms such as the indestructible water bears that can survive in the harshest conditions that Earth, and even space, can offer. In this book we shall take a tour of the astrobiological Universe, exploring what life is made of, what it needs to originate and thrive, how resilient and adaptable it can be and what is next for humanity as it steps off the Earth and into the realms of the unknown. How and when will we do this? Or is it all just science fiction? This book is an accessible introduction to the most fascinating of all the astro-sciences – Astrobiology. Goldilocks and the Water Bears is a scientific fairy tale of the origins and evolution of life on our planet and the quest to find it on other planets and moons, in other galaxies, and throughout the Universe.