Expert: Jayendra Upadhye - 10/22/2005

Question
I know this may sound stupid, but what if, we excavated the earth to a point where we made it into a cube, and shipped off all the soil to space, firstly is this possible, and secondly how would this affect the laws of physics, and when you would come to a corner of the cube?

Answer
Hi monty!
Strange you should ask a question of such fundamental value in understanding basic science.

Takes some courage to do that.

Actually it is impossible to do this sort of thing for a very simple reason! the earth's gravity is strong enough to pull "all major projections" (read that as tall mountains) into shape.

The earth's crust is only just SO strong as to support mountains upto 8 to 9 km in height. Any mountain that rises above that limit, just crumbles under its own weight along an imaginary 45 deg cone!

Have you wondered why many mountains viewed edge on actually trace 45 degree slopes up to the peak? The reason is what i just cited above. the rocks simply fracture and shear along that "shear plane" and maintain their peaks around a maximum of 8 to 9 km.

On mars, the gravity is lower than on earth, so it sports "olympus mons", a volcano 15 km tall! and several 10s km in circumference at its base.

By same logic if there were ever a terrestrial (solid) rocky planet 10 times the size of the earth, in all probalilty, the mountains there would be few 100 meters high and no more! the rest of the surface would resemble a highly polished sphere!

So in your cube case, as the cutting progressed and the corners started to resemble colossal mountains, they would tumble every time they stood out more than 9 km from their semi cut bases, and the cutting would have to start all over again!

After most of the earth had been cut away like that, you could get a self supporting cube when the earth had been whittled to the size of 50 or 100 km!
By then it would be no more than an asteroid.

What a waste of time and effort THAT would be!
Jayen