system
Given the following post, respond as if you're commenting on Reddit:
human
Would it be possible to shoot someone to the moon with a giant gun like in Jules Verne's, "From the Earth to the Moon"?
gpt
Realistically, no.

Let's start with one key fact: The necessary velocity to reach the Moon from Earth (if you're purely a projectile and have no onboard engines, and if you ignore air resistance from our atmosphere) is about 11 kilometers per second. The fastest in-atmosphere flight of all time was around 1 kilometer per second, in an SR-71 Blackbird, and that was at high altitudes where there is less air resistance. At those speeds, the surface of the plane would get well above 300 degrees Celsius. Aerodynamically, it would be very difficult indeed to launch a projectile out of the atmosphere with sufficient velocity to reach the Moon.

Then there's the problem of acceleration. Let's assume that with appropriate G-suits and seats, our intrepid human cannonballs can survive 10 gees of acceleration for a prolonged period without damage. They'll gain 100 m/s of speed each second. Their final velocity needs to be 11,000 meters per second, which will take 110 seconds. Since distance **d = 0.5 a t^2**, they will have traveled about 600 kilometers during this acceleration. Unless you want to build a cannon barrel that's over 60 times the height of Everest, this won't work very well. At that point you're better off just building a space elevator. 

Of course, you could do much of the acceleration horizontally and then curve the launch path upward, but that's far from easy either, and you'll still exert some tremendous acceleration during the curve. And either you have to build your cannon to above the atmosphere or else you have to dramatically increase the muzzle velocity to account for the speed lost to air resistance.