As a science-fiction fan, I am often asked, “Star Trek or Star Wars?” It seems an odd question. When I go into the fish-and-chip shop, nobody says, “fish or chips?”. Star Trek and Star Wars are different in many ways, but are also complementary. Both franchises have enjoyed recent and largely successful rebirths, with director J J Abrams rebooting them to critics’ (and most fans’) delight on the big screen, while on the small screen, Star Trek Discovery is entertaining new and established audiences. It’s no surprise, then, to see new books exploring the science of each coming out. When Physics World asked me to review astrophysicist and science writer Ethan Siegel’s Treknology: the Science of Star Trek from Tricorders to Warp Drives, I did not want to be accused of favouritism, so I suggested I might also review The Physics of Star Wars: the Science Behind a Galaxy Far, Far Away by physicist Patrick Johnson, from Georgetown University in the US. So buckle up as we navigate our way through these binary stars of science fiction. Star Trek has always been synonymous with science. It has inspired countless of today’s scientists and astronauts, with NASA astronaut Mae Jemison even famously appearing as a character on the show. But at the same time, it’s not exactly “hard science fiction” of the likes of Gattaca or Robot and Frank. There’s Treknobabble – “Chaotic space intersects ours at the 18th dimensional gradient. Voyager entered through a trimetric fracture” – and for every scientifically accurate slingshot round a planet, there’s a “spore drive” able to jump a ship to anywhere in space and time…and even, occasionally, travel into other universes. Siegel says that, for him, it was science first, and then Star Trek. As a child he fell in love with the ideas of exploration and discovery, dreaming of finding new worlds and alien life. So when Star Trek: the Next Generation hit our television screens 30 years ago, the young Siegel was delighted to find a show that shared his desire to go where no-one had gone before. Treknology is a beautiful book, full of imagery from the Star Trek franchise, and a few descriptive diagrams to accompany the science discussed in the text. While flicking through the book is an enjoyable experience, this is no coffee-table tome. To treat the text as secondary to the images would be a mistake. Siegel’s writing is well known to many who follow his Starts with a Bang blog on Forbes, and that same engaged and enthused writing fills this book. The doctor will see you now A book on the science of Star Trek is perhaps an easier sell than one on the science of Star Wars, what with its hokey religions and ancient weapons, and Johnson addresses this in his introduction. In fact, the entire book provides an answer to the argument that Star Wars, being arguably more fantasy than science fiction, is not fertile ground for discussing physics. Johnson succeeds in doing just that in an engaging and entertaining way. The book itself is relatively unremarkable to look at. Johnson mentioned to me that he was told from the start that the art department was not going to be giving him any help at all, and it shows – the book doesn’t contain a single image. In fact, its design owes more to textbooks than the coffee-table book one might expect for such a topic. The only colour is the yellow title on the front cover, which also includes a disclaimer to avoid being sued by Disney or LucasFilm. But Johnson’s writing, filled with humour and a clear love for both Star Wars and physics, ably counters anything lost by the lack of images. I found myself swept along with his enthusiasm, and the textbook format is lost to a galaxy of memories of the films, mixed with a wide ranging and thoroughly entertaining romp through the physics of both our galaxy and the one far, far away. Each book is divided into sections. Treknology has starship technology, weapons and defence, communications, computing, civilian technology and “medical and biological”; while The Physics of Star Wars is divided into chapters on space, planetary science, planet-based transportation, space travel, handheld weaponry, heavy weaponry, robotics and, yes, even “The Force”. We’ll come to that but wait for it, you must. Treknology is not the first book on the science of Star Trek and its section on starship technology contains information that has already been explored in previous books. We read about warp drives, tractor beams, transporters and the like, but it is also a delight to find science not covered in those other books that tackle the science of the Star Trek franchise. Set phasers to stun Synthehol, for example, is an alcohol substitute in later Star Trek series with all the intoxication and improved confidence alcohol can deliver, but none of the hangover, upset stomach or blurred vision. Even better, the intoxication can be removed by an adrenaline shot in an emergency scenario, leaving the drinker stone-cold sober – handy if you suddenly need to control the Enterprise or defend your crew from a Borg assimilation attempt. Siegel explores the chemistry and physiology of how this might be possible, and discovers that substances with some of those properties might not always be fictional – indeed, some have even been trialled in the real world. There are other, more classic, examples of how Star Trek was a forerunner to the technology we use in our daily lives, with flip communicators and personal-tablet devices looking almost eerily similar to the phones and computers so many of us use. But what of seemingly more far-out tech such as the “replicator”? In Star Trek, crew on board the spaceships are able to ask the computer to recreate any food for them and, thanks to the replicator, it appears in front of them, ready to eat. That seems a distant dream, if not impossible, but on board the International Space Station today there are astronauts for whom 3D-printing food is a reality already. Despite the title of Johnson’s book specifically mentioning the physics of Star Wars, he does touch on other sciences – it would be a strange galaxy where one could consider life using physics alone – but the core of the book is focused on physics. For most physicists, there is a particular scene in Star Wars that causes reactions ranging from amusement, through a slight jarring, to outrage. Drinking in a bar full of undesirables from across the galaxy, our lovable rogue, Han Solo, claims that his ship, the Millennium Falcon, is so fast that it can do a particular route – the infamous “Kessel Run” – in “12 parsecs”. Did George Lucas, when writing the script, make a schoolboy error, using a unit of distance where he should have used one of time? I doubt anybody seriously would think otherwise, but Johnson posits some post-rationalization to put your belief safely back in suspense. Johnson argues that we often interchange distance and time in everyday life: the answer to “How far is it to the shop?” is often “About 15 minutes.” Similarly, obstacle courses are not always about the time taken. What if the Kessel Run is a competition to see who can successfully navigate, for example, a series of black holes in the shortest distance? That would take a seriously fast ship, to get close enough to, but still escape, the gravitational pull of these stellar giants, and would also require an impressive pilot with excellent manoeuvring capabilities to pull it off. Suddenly Solo isn’t wrong, but just his usual boastful self. Could this newly imagined Kessel Run course be an exhilarating scene in the forthcoming film about Solo’s younger years? That’s not to say that Johnson’s book sets out just to rationalize apparent scientific inaccuracies of Star Wars – the tone is more of a discussion of the issues, and he is equally at home calling out scientific nonsense in the franchise. Starkiller Base, for example, is “impossible” but rather than getting stuck on that or allowing it to spoil his enjoyment of the film, Johnson uses it as a springboard to discuss hyperspace, dark energy, plasma and electromagnetic fields, before eventually comparing “the most impressive weapon in Star Wars” to the Large Hadron Collider at CERN. His writing style is almost conversational, leading the reader to feel as though they are chatting to the author in somewhere considerably more salubrious than the Star Wars Cantina. The section on “The Force”, the magical power that surrounds and guides everything in the Star Wars universe, takes the reader on an exploration of the potential scientific explanations of the topic through parasitic worms, James Randi’s never-won million-dollar prize and the bacteria in the human gut. This kind of wide-ranging exploration will leave you amused, and with a burning desire to promptly watch six of the Star Wars films all over again. (There’s very little that could make someone want to watch the other three, ever. Even if you are tempted, please do not do it. They are as bad as you remember, particularly Attack of the Clones.) Anybody who watches Star Trek or Star Wars hoping to find a wholly scientifically accurate portrayal of a possible future (or distant past), will be sorely disappointed. One of the great pleasures of both franchises is the conversations between friends about the science fact, science fiction and everything in-between of each episode or film. Both these books serve to arm the reader with a wealth of data for such interactions. Johnson told me that he has equal love for both physics and Star Wars, which, he claims, makes him “a winner at parties everywhere”. Exploring the science of each franchise is hardly going where no-one has gone before, but both of these books would be welcome additions to the collections of any science-fiction fan with the slightest interest in actual science. Both Siegel and Johnson’s books can be read cover to cover, or dipped into as reference books. They are equally fun to read, offering a fascinating and entertaining ride through the science in an accessible way, without speaking down to the reader or oversimplifying complex issues too much. There is plenty to learn in Treknology for even the most avid Physics World reader. The physics sections undoubtedly cover enough areas to ensure that the majority of readers maintain their interest, but there are a host of sections on other aspects of science from physiology to chemistry and climate science. Neither book would render the reader an expert in physics, but both would undoubtedly give a greater appreciation and understanding of a wide variety of topics within the field. While Treknology does feel like the more impressive book at first glance, with all its glossy imagery, there is just as much joy and exploration of fascinating topics in The Physics of Star Wars. Like fish and chips, to choose between them, needless it is and, I dare say, somewhat futile. Ethan Siegel Treknology: the Science of Star Trek from Tricorders to Warp Drives 2017 Voyager Press £19.99hb 216pp Patrick Johnson The Physics of Star Wars: the Science Behind a Galaxy Far, Far Away 2017 Adams Media £10.98pb 256pp Enjoy the rest of the February 2018 issue of Physics World in our digital magazine or via the Physics World app for any iOS or Android smartphone or tablet. Membership of the Institute of Physics required