Yeah there already exists some tech infrastructure that is protected against carrington-level solar flares. But I bet it's less than 1% of it all because of the costs involved. When it happens it's gonna be real chaos worldwide. We can only hope it doesn't happen in our lifetime, but it's eventually gonna happen.
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I think thats why we shouldnt be too dependent on digital stuff. Also, there needs to be a decentralized phydical network infrastructure specially designed for Bitcoin, to make it really resistand. Maybe even against solar farts.