I wonder if a lead/gold-core tungsten rod of death to drop on targets would work better than the above? Or would it be a bunker-buster so heavy and hard, it would collapse mole-people cities?
Talk about raping your enemies; You'll impregnate the earth with this, and it'll give birth to a true Earth-child. Armok.
EDIT:
Depleted uranium would work too. And not just a telephone pole size, but something the size of a rocket booster. We have a MOAB, so why not a FOAB?
The good folks at the RAND Corporation did a
rather nice monograph on orbital weapons about 10 years ago. Used it as a primary source for a grad paper on space weaponization.
The looked at four main categories: ICBMs, kinetic-energy weapons (your concrete telephone poles), directed-energy weapons (mostly in the context of anti-ICBM defenses), and
lobbing very small asteroids.
Broadly speaking, they recommended tungsten rods for precision strikes. The rod shape causes the impact crater to be more cylindrical than spherical, so you get less collateral damage and more penetration. Tungsten bleeds heat pretty well, though ablation would still be significant.
For example, a 1-m-long tungsten hypervelocity penetrator should be able to penetrate about 1.5 m of steel, almost 3 m of clay or stone, and 1 m of uranium. What penetrates through that depth (or less) of target will be a very hot mixture of target and penetrator material and any remaining penetrator length. The damage is done almost entirely in the direction of the impact, as with a shaped charge explosive, except for damage caused by secondary fires or explosions ignited by the impact.
However, rods are horrible at aerodynamics, which presents an engineering problem. The more spherical, the more even the ablation and the less accuracy and energy you lose due to wobble. But the more rodlike, the more you concentrate your blow into a single deep strike. If you just want to blow shit up indiscriminately, they recommended something of a compromise -- an elongated oblate tungsten spheroid.
Bottom line: dropping tungsten cores from space makes a really nice anti-bunker weapon, not so much a weapon of mass destruction. The projectile loses a lot of kinetic energy to friction and ablation in atmosphere. To get city-busters, you'd have to drop chunks of metal that were already in the kiloton range to begin with. That's where the "lobbing tiny asteroids" part comes in (although ridiculously expensive to find, tow and propel an asteroid...not to mention attempting to impart any kind of accuracy to it)