The famous photograph of the Earth from the vicinity of the Moon taken by the astronauts of Apollo 8 on 22 December 1968. Courtesy NASA
Round the Moon by Jules Verne. Free ebook available in a variety of formats from Project Gutenberg
I have recently read this book by Jules Verne and was struck by the number of uncanny similarities between this imaginary voyage that Verne describes as happening in the 1860s and the first lunar circling mission of Apollo 8 made a century later. What is also fascinating is to see how impossibly difficult such a voyage would have been at that early date without the benefit of the electronics and radio communications that were available to the Apollo 8 astronauts. As well, part of the fun of reading this book is to see what parts of the science of a lunar mission Verne gets right and what he gets wrong.
Round the Moon is a sequel to From the Earth to the Moon. This first book tells the story of the construction of a giant cannon to shoot a shell to the Moon. It is a project of the Gun Club in Baltimore, USA, that was set up by former military artillery officers. With the advent of peace after the American Civil War of 1861-1865 these officers were getting bored and their president thought that they needed a major project to boost their spirits.
The 274-m long cannon was set up in Florida to shoot the projectile at the Moon. Initially, the 2.7-metre wide projectile was to be unmanned but a French adventurer arrives and insists on riding inside the capsule and persuades the president of the Gun Club and his chief critic to join him.
Round the Moon begins just after the projectile had been fired. The three occupants survive, of course, in the book. Should they have? According to my calculations to reach the target velocity of 11 km/s, the Earth’s escape velocity, in the 274-metres long gun barrel, they must have traversed it in 0.05 seconds and experienced an acceleration of 22 500g! For comparison, the highest accelerations that humans are known to have survived have been the 100-200g experienced by racing car drivers involved in crashes.
Leaving the miraculous survival of the three pseudo-astronauts aside, during the journey there is a lot of fun conversations and interesting speculations about the possibilities for an atmosphere and inhabitants on the Moon. The travellers miss the Moon as on the way they happen to have an encounter with an unknown satellite of the Earth that deflects the spacecraft into an orbit around the Moon. Fortuitously, but just a little implausibly, a later encounter with a giant asteroid deflects them on a path back towards the Earth. Very cleverly, Verne has them travelling at full Moon, so that when they are flying over the unseen side of the Moon it is unlit by the Sun and so the travellers can see nothing of the then unknown surface.
Some of the science in the book seems be correct, but there are quite a few errors. The travellers still experience the Earth’s gravitational pull as they fly away from the planet with just the normal diminution by the square of the distance. The only time they find themselves in zero gravity is when they reach the point where the gravitational forces of the Earth and the Moon are in balance (the L1 point) and afterwards they feel the Moon’s attraction. Of course, a spacecraft moving along an orbital trajectory is basically in free fall and so the environment should have zero g, or more correctly, microgravity.
The book is most enjoyable to read with lots of banter between the three travellers and interesting descriptions of what the surface of the Moon facing Earth would look like when viewed from close-up. For a modern reader though the best part is to find the parallels to the Apollo flights a century later, especially that of Apollo 8 that first looped around the Moon, and to consider the science given in the book to see what is right and wrong. I have mentioned a few problems that I have found in this review, but there are others. For instance, check out the discussion of what a lunar eclipse may look like from the Moon.
For me, possibly the most important aspect is how Round the Moon highlights that until the right technology comes along, such as rockets, electronics and wireless communication in this case, many projects are impracticable and can only be achieved in the imaginative mind of a clever writer of fiction.