Ah good, so he was at least in a realistic ballpark for how thinly he’d have smeared the crew against the aft bulkhead, in spite of his technobabble shock absorber…
I read a review of FtEttM once that said that Verne had correctly anticipated all the problems with his proposed flight, and then explained them all away, with handwavium of necessary.
I take issue with JR’s saying that Verne “wasn’t a science fiction writer, of course”. There’s no “of course” about it. Verne definitely was a science fiction writer, even if folks like Walter B. Evans try to make out that he wasn’t. He clearly researched his topics heavily, extrapolated from known facts, and tried to show how they affected people and how people reacted to them. He ran into problems whgen there wasn’t enough easily accessible material on his topic, as in thus case.
Verne correctly chose Florida as his launch site (and had sort of “mission control” in Texas, amazingly enough, where they set up a large telescope to watch). His projectile was made of aluminum, chosen for its combination of strength and light weight. They had chemicals on board for scrubbing carbon dioxide and releasing oxygen. And his bullet-shaped ship was just about the size of the Apollo craft (without the LM). Verne painstakingly plotted the course around the Moon, describing the features it passed over, had the ship use rockets to adjust its orbit, and had it come down in the ocean for a relatively soft landing. Verne even had a “count up” at launch, with the crowd chanting from zero to ten, instead of a “countdown” going to zero*
Of course, his “lunar cannon” was a ludicrous way into orbit, because the acceleration would’ve been more than lethal. I suspect that Verne was well aware of this, and simply ignored it so that he could go on with his story. This was years before Konstantin Tsiolkovsky or any of the early rocket pioneers wrote their speculations about the practicalities of rocket flight, and at least a giant cannon was more realistic than any of Cyrano de Bergerac’s proposed methods of flying to the moon. (Edward Everett Hale wrote a four-part story about the first artificial satellite, which was manned, in 1869 – The Brick Moon – four years after Verne’s book. It’s sadly pretty neglected. He had his launched using a sort of giant slingshot, which would still have the same problems of acceleration.)
Verne must have realized how his “assumption for the sake of the story” appeared, or had it pointed out to him too often, because he wrote a much-neglected second sequel to From the Earth to the Moon, Sans dessus dessous (translated as “Topsy Turvy” or “The Purchase of the North Pole”), in which the Baltimore Gun Club plans an even more outrageous undertaking, and carries it along for a time, until someone does the calculations and shows them that their idea is completely unworkable.
Apparently the length of the gun barrel in From the Earth to the Moon is too short to let them achieve escape velocity.
Also, Verne really had no good idea about how orbital dynamics worked. He imagined that they basically had to go to the L1 Lagrange point between the Earth and the Moon, give the craft a push, and then “fall” into the Moon’s gravitational potential well. (That’s the reason they were at that point to experience Verne’s mistaken idea of weightlessness). I have a book on orbital dynamics that points to this as a classic mistake in thinking about orbital paths, although it doesn’t actually name Verne**.
Exactly why Verne had this odd idea that you would only have weightlessness at L1 is something I don’t understand. As observed above, Verne correctly observed that the body of the dog that had died, thrown out of the ship (through the airlock) did not drift away, but stayed with the ship. He similarly properly explained in Hector Servadac (“Off on a Comet”, his other outer space adventure) that the breakup of the cometary body would not result in any changes of velocity, since all the components would still travel at the same speed next to each other. From all of this you’d think he would realize that the bodies of the space travelers, even though inside the space ship, would have been effectively weightless.
Maybe he simply didn’t want to deal with having his characters floating around inside the ship for the whole story. Unlike the writers of Star Trek, he didn’t have he concept of Artificial Gravity to play with, so he simply ignored it, except for a brief Lagrangian interlude.
*As far as I know, the first “countdown” in science fiction was in Fritz Lang’s Die Frau im Mond (“Woman in the Moon”), made with the help of rocket pioneer Hermann Oberth.
**I wonder if Verne got his weird notion of how gravity worked from Edgar Allen Poe. Verne was a big fan of Poe and admired his proto-science fiction efforts. Verne’s “get to L1 and turn around” orbital dynamics resemble those used by the protagonist in Poe’s The Unparalleled Adventures of One Hans Pfaall, who got to the moon in a balloon made of old newspapers.
To elaborate, Verne envisioned explosive power but even modern rail gun technology is nowhere near the energy required. To accelerate Verne’s “10 ton” vehicle to escape velocity would require about 263 gigajoules, and that assumes 100% efficiency. The most powerful magnetic rail gun tested thus far is about 32 mega joules or very roughly 1/10,000th the energy: https://www.popularmechanics.com/military/a2289/4231461/
But the actual energy isn’t that great - 263 gigajoules is “only” 73 megawatt hours or less than 10% the output of a typical power plant for 1 hr. However storing that and productively releasing it is another matter.
There is no technology that can store and release that amount of energy within the approx. 22 sec. a 50-g boost to escape velocity would require, so it would have to be generated “on line”. That would require 3.6 gigawatts electrical at 100% efficiency, or probably 5 gigawatts including some losses. So just to power the apparatus would require five 1 gigawatt plants (gas turbine, nuclear, etc) in parallel.
Even at 50 g acceleration, the gun “barrell” would be about 80 miles long and would likely have to be pumped down to a vacuum. Maybe if the end was open that would suffice since 80 miles altitude is space.
In theory humans using fluid breathing and fluid immersion can tolerate much higher g forces. I have seen speculation that maybe 1,000 g might be survivable but even at 500 g the “gun” would still be eight miles long. Since exiting the barrell would still be within the atmosphere there would be tremendous deceleration and thermal factors, far worse than an Apollo capsule returning from the moon.
The shorter boost time also worsens the energy generation problem since 263 gigajoules must be released within 2.2 sec at 500 g, which equates to about 119 gigawatts for 2.2 sec at 100% efficiency.
An airbreathing aerospaceplane, a space elevator, an Orion nuclear pulse rocket, or almost any other conceivable method - however outlandish and expensive - would be more achievable.
The one thing I have never seen addressed with liquid breathing while immersed in a liquid environment is dealing with air trapped in middle ear chambers or sinuses. A SCUBA diver can equalize his/her ears during a slow, controlled descent/ascent in the ocean, increasing the ambient pressure on their body by maybe 1 atmosphere every 15 seconds. And they have the ability to pause their ascent/descent if they are having trouble with equalization.
The equivalent acceleration ramp rate during a rail-gun launch would need to be no more than 1 g every 15 seconds, dramatically increasing launch time and rail gun length - and there likely wouldn’t be any pause in acceleration ramp-up if any if the passengers complained about trouble equalizing their ears. So if you’re going to be exposed to extreme accelerations and/or rapid acceleration buildup rates (high jerk), while immersed in liquid you need to completely fill your tympanic cavities and Eustachian tubes with liquid. If there’s more than a smidge of air left in there, then when you and your liquid bath accelerate, the increased liquid pressure on your body will compress that trapped air and rupture your tympanic membranes.
Handwavium it is. It would be a very short novel otherwise…
Many science fiction writers expound ideas which require some “suspension of disbelief”. For example, calculating escape velocity is a waste of time considering how hot a capsule gets on re-entry - a capsule going miles-per-second at sea level probably would be cinders before it reached the upper atmosphere, plus would slow down dramatically. Anyone who knew about meteors would know about this. Ignore these because they simply make the story complicated.
I think the launch Verne knew instinctively was a lethal idea, but figured with gargantuan sizes and handwaving the calculations could make it seem plausible enough to get past it an into the rest of the story.
Verne made some best guesses with the facts known at the time.
A speculative answer from history, going in the “correct” direction:
From Operation Plumbbob - Wikipedia
So attempting to attaining escape velocity while still in the meaty part of the atmosphere would almost certainly end badly.
Meteors going the other way tend to become spectacular vapor, I don’t see why starting from the ground would end any differently.
The meteor which was captured on a number of assorted video cameras in Russia a few years ago was allegedly the size of a 5-story building, and yet there was no evidence any of it reached ground level. What hope for a hollow metallic object? All that kinetic energy converted to heat…
It’s much worse starting from the ground. Coming in from above, you hit the least dense part of the atmosphere first, slowing you down slightly before you hit the more dense part of the atmosphere. Starting at the ground, you hit the most dense part of the atmosphere at the highest speed.
Yes, not just friction but deceleration forces from wind resistance like hitting a brick wall at 7 miles a second. The projectile would probably pancake before it disintegrated and vaporised.
Actually, they recovered quite a bit of material. The largest piece they found was 1442 pounds.