[hammyhavoc]

I'm more concerned about what's already within our atmosphere and isn't going to burn up. That's a lot of kinetic energy, and nobody says it's going to destroy the Earth, I said it would be devastating.

You're forgetting religious extremists and countless suicide bombers.

[ta1243]

It would be cheaper to drop an equivalent massed object out of a plane. Or just use the plane as the weapon.

You break a space elevator at the ground, it floats upwards.

You break it at 30,000 foot then everything above the break floats away upwards, everything below "crashes" down, at a relatively low terminal velocity and thus with pretty low amounts of energy.

An elevator isn't a tower, it's a rope handing from a counterweight in orbit which is kept taut by a centrifugal force. It's anchored at the ground to stop the rock floating away, but if you break that anchor everything above will swing away from Earth

If you have the ability to break the cable at say 100km above the ground, you have the ability to drop objects from that height anyway, don't have to deal with no-fly-zones, and can target somewhere not on the equator.

Want to cause chaos? Get a bunch of heavy dense cheap bits of metal, put them in a high altitude balloon, then drop them over a city. You'll cause more damage to the people on the ground than anything you could do to a space elevator (short of the financial impact of having to resplice it)

If you can damage the elevator at the counterweight end, then you have the ability to drop a "rod from god" and cause more damage that way.

[robocat]

> "crashes" down, at a relatively low terminal velocity

I would like to see an analysis. 100’s of tons of string falling and accelerating the surrounding sheath of air (acts absolutely nothing like a meteorite). A good physics question!

[Retric]

That’s assuming you can’t say detonate a bomb inside the cargo thus resulting in vastly longer section falling down.

Space elevators are inherently create a new safety risk as cutting them at geosynchronous orbit only takes compromising some security and building a modest bomb. Both of which are achievable by terrorist organizations.

[Retric]

Accidentally deleted a bit: Space elevators are inherently a means to reach orbit so they create …

PS: 911 didn’t happen because terrorists suddenly figured out how to build giant aircraft to douse buildings in tons of jet fuel they subverted an existing system that solved 99.9% of the technical problems. Thus by getting a few violent individuals on board with simple weapons simplified things to only needed to fly an aircraft that someone else built, got into the air, and filled with fuel.

[seanc]

That's true-ish, but don't forget that a space elevator is also an enormous amount of orbiting mass all on it's own. So a small bomb can cause it all to come down and wrap around the planet twice.

[ben_w]

For a ring with a density of 10kg/m, that kinetic energy is about 5 megatons… spread over 40,000km.

It's negligible when it's that diffuse. Even if it didn't burn up, it's mostly lost to air resistance, with everything over a few hundred meters being limited to about terminal velocity.

And that size ring, is pretty useful.

[hammyhavoc]

https://www.wired.com/story/what-happens-if-a-space-elevator...

[ben_w]

That fails to illuminate very much.

Also, ring != elevator.

Probably still want to engineer it such that destruction is controlled rather than uncontrollable, but the biggest issue with it being destroyed would be no longer having it; the damage would be mostly within a meter or so of where it lands, which isn't great but it's also not devastating unless you happen to be that close.

Think a very long I-beam falling off a skyscraper during construction, not an asteroid.

[outworlder]

Assuming the cable is rated for the sudden force changes and won't get split into a whole bunch of smaller pieces that will drop at just their terminal velocities. Think a shower of cable pieces rather than a whip. Not great, but it's likely that most of the energy will be dissipated by the atmosphere.

[nonethewiser]

And you’re both forgetting war.