If only for the sake of completeness, this experiment ought to be performed. To me it seems a glaringly huge gap in our knowledge of gravity that we do not really know how objects fall through the centers of other massive objects. In all known cases, radial falling motion always ends with a collision. Why not let one body fall radially into another body to see what happens when there is no collision?

At the website GravitationLab.com other reasons are given for wanting to do the experiment.

We have been discussing till now that we need to dig deep straight, reach the earth crust and come up exactly upwards on the opposite direction. Say, the Newzealand and Spain example which are geographically the opposite and straight if we travel through earth’s core.
But what if we never think of reaching the earth core and travel rather shorter distances. All’s well, the gravitaional force, the air pressure, the frictional forces come into much consideration when we have to ACTUALLY REACH THE EARTH’S CORE.

WHAT IS WE NEVER REACH THE EARTH’S CORE? Imagine a circle, rather than a sphere for a moment. Uptil now we have been talking about travelling as a diameter of a circle thus we reach the two extreme points of the circle. What if we consider different chords of the circle and travel from one point of the circle and reach another, much closer point not reaching the core. This will leave us of some considerations of physics be it the gravitional forces, etc.

Naturally, the gravitational force acting at the earth’s core is the maximum so we never need to consider the extreme force. Imagine a place China, if we go straight, we will land on Argentina on the other side, but we are passing the core in this way. Instead, imagine travelling from China to North America, that will make a chord in the circle have shorter distance.

Now imagine going from North America in a different tunnel straight, this will open somewhere in the Indian Ocean. Rather, imagine going to Australia from North America, this will make the 2nd chord of the circle. Now imagine the 3rd chord from Australia to China, short distance thought but just for the sake of connecting places.

If you imagine these THREE CHORDS inside earth’s sphere, you will come to realize that none of these have actualled travelled throught the earth’s core. I am no man of physics but I am sure this will create less troublesome gravity train routes, some which we might believe to be true.

Once a 15th century man thought that we might one day land on moon. People laughed at him, but our great great grand fathers and forefathers never thought we would one day be using cell phones.

It also occurred to me that rather than using magnets and/or electromagnets to reduce friction just use a cushion of gas. If i remember correctly heat can destroy magnets by rearranging the atoms but don’t quote me on that.