Yes, this is what I’m getting at. Every part of your body would be getting pulled by equal force in all kinds of directions, wouldn’t it? I was thinking that something would happen to you in that situation.
If your head and feet are getting pulled opposite ways by equal gravity, that doesn’t seem like it would be good.
Right exactly at the center, a particle would be pulled in all directions at once, but that all cancels out to nothing, so it doesn’t matter. It’s not like the gravity from one side is pulling on one part of a particle, while the gravity from the other side is pulling on a different part to pull it apart; everything’s affected by all of the gravity.
Now, a human is not a point mass, so not all of a person would be quite exactly at the center, and away from the center the forces won’t quite exactly cancel out and there’ll be some force left over. But very close to the center, that leftover uncancelled force will be very close to zero, so it’s still no problem. Imagine standing between a couple of big boulders, a few feet apart from each other: That’s about the same amount of gravitational force you’d get here.
Note that while there would be no air in the tunnel, and therefore you wouldn’t slow down due to friction, you’d pretty quickly bump into the sides of the tunnel even if you were aimed perfectly down the center. Unless the tunnel were from the Lunar north pole to the Lunar south pole. The Moon rotates on its axis once a month. When you’re at the first opening about to fall, you’ve got the same vector as the surface of the moon you’re over. But as you fall, you keep that same vector, yet the tunnel around you is changing direction. But you’re not changing direction, you’re in free fall. And so you bump into the wall.
Even if the tunnel was from North pole to south pole, you’d bump the wall eventually because the Moon is in orbit around the Sun, but the lunar poles aren’t perfectly aligned with the Moon’s rotation, it has a small axial tilt.
If it weren’t for that, you’d oscillate back and forth between the ends of the tunnels, because the speed you’d be going as you passed the center of the moon would be exactly the speed you’d need to be tossed up to the other side of the moon. Assuming that both ends of the tunnel are at exactly the same distance from the Lunar center of gravity, that is. If the first end of a tunnel was on a highland compared to the other, you’d be tossed up out of the tunnel and only stop when you reached exactly as high as you fell from on the other side.