• tryptaminev 🇵🇸 🇺🇦 🇪🇺@feddit.de
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    1 year ago

    It is simple conservation of energy. All the energy that creates the impact, must come from somewhere. A huge metal rod that lies on the ground is not going to cause any harm, aside from stubbing toes maybe.

    Leaving small height differences between the rockets launch site and the final impact site aside, the energy comes either from the rocket that brings it into space, or from propellent that the metal rod uses when launched on its target (it being a missile itself). So you end up at minimum with a rocket to transfer the whole thing into orbit, that is loaded with fuel with the same energy as the energy at the impact site. Given the rocket fuel problem, it is much more fuel, as you also need to carry the fuel for the later stages of the transport rocket up too. Then you also need additional energy for the friciton and to steer the metal rod into its designated target.

    Either way you end up either having to assemble the weapon in space, or having a rocket fly into space with enough fuel to release more energy than the weapon could release on impact. So in terms of the claim of force akin to a nuclear weapon, you also need fuel with enough energy like a nuclear weapon.

    Gravity does not help at all. You cannot “imbue” an object in an energy field with more energy, than you spend on changing its position gainst the field.

    • Buelldozer@lemmy.today
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      1 year ago

      Conservation of Energy only applies in a closed system. If the rod is built on the Moon and then placed in Earth orbit it’s quite possible to be net positive energy relative to Earth’s gravity field.