Don't say it's impossible, trying visualizing a nuclear outbreak between two edging nations in the world and you would have a deterred usage of the entire internet and eve the satellite internet
These can't really stop it. If two nations head into war via nuclear weapons there would be places and nodes that won't be affected
And even if the traditional internet shuts down
It would still be almost impossible to stop it because people could still transact through local network, or satellite foe Bitcoin created by Blockstream or through a mesh system.
Though it could affect it, in the long-run Bitcoin principles makes it hard to 'kill'.
OK, sorry. Unless a nuclear outbreak happens, or aliens invade the planet, or a meteor strikes the Earth.
The Aliens may get fascinated by the system
Who knows