This actually works. All you have to do is decelerate the train once (because it's spinning with the world while you build it).
And solve the trivial engineering task of reducing all friction and air resistance to zero. Oh, and that of getting on and off the train.
And solve the trivial engineering task of reducing all friction and air resistance to zero.
Well shit, anyone can do that. Just put a little WD40 on it
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You build your track dead straight - like, not conforming to the surface direct through the crust straight. Now the train accelerates downhill for the first half of the journey, and decelerates uphill for the second, neatly coming to a stop at the destination. Oddly enough, in the spherical cow universe where you build this, all the maths cancels such that you get a constant travel time regardless of the start and end locations. On earth it's about 40 minutes
you could conceivably get on and off the train with shuttle "station" trains that travel on parallel tracks to catch up with the main train
🤔 A vacuum tube maglev would do the trick.
Actually Isaac Arthur talks about something like that on his channel. An Orbital Ring, he calls it.
I think I had this idea when I was ten. I knew I should have patented it. Fuck.
I swear I came up with the iphone... my design was a triple flip phone, screen up top, keypad in the middle and an ipod wheel down bottom
Why? Because fuck physics, that's why!
Just tie it to the moon.
It's a high tide train ride!
Or to the sun
Ride the tides then
This would be possible if there was a material unaffected by gravity, right?
I think in that case, the earth would just depart the location of the train, leaving it drifting in space.
I was assuming the rails are strong enough to keep the train on the Earth, but I guess infinite friction from the movement and rotation of the Earth probably isn't survivable by any railway material. Hypothetically, if you had a material unaffected by gravity (train), and a material that is absolutely invincible (the rails, and they are anchored to the center of the Earth), now does it work?
It's impossible to even reason about what something entirely unaffected by gravity might or might not do because everything, including gravity, is relative. Something not affected by Earth's gravity would probably get carried away by the wind, but something not affected by the Sun's gravity would float away from the sun (relative to the Earth) and appear to have some sort of mysterious acceleration from our perspective. If the object isn't affected by the Milky Way's gravity, even more shenanigans.
No, the problem is not gravity, is that the train attached to earth has velocity dictated by the Earth movements, and keeps it because of inertia. In your theoretical experiment, the train would be launched on space at constant velocity.
The problem isn't gravity, it's friction. The train would functionally be in orbit. The reason why things can't be in orbit at ground level is not because of gravity but because of friction (incl. air resistance).
If you eliminated friction (vacuum tube, frictionless surface, etc.) you could indeed have the train moving without any additional energy after getting it up to speed (and if you get it up to orbital speeds, the frictionless surface isn't even necessary). However, this isn't really practical (obviously).
If there is a nugget of a good idea in here, it's a train that never needs to accelerate or decelerate, just maintain a constant speed. Much of the energy of a train is lost in the stop-and-start.
