cryptocurrency network behaviour during blackouts

[Morbid]

what if theoretically we might experience power or internet shortages around the world. or if a continent gets separated from www and operate as separate nod - would we have two parralel blockchain versions? what would happen to crypto networks in that case? are networks protected against blackouts?

[stash]

Nice question, this is worth topic to read before going to bed. Waitin pro for an answer 

[Rannasha]

If two parts of the world become disconnected for whatever reason, each fragment will continue operating on its own fork of the blockchain. Once these parts have reconnected, clients will automatically accept the longest of the two chains, invalidating everything that happened on the shorter chain since the split.

[Morbid]

If two parts of the world become disconnected for whatever reason, each fragment will continue operating on its own fork of the blockchain. Once these parts have reconnected, clients will automatically accept the longest of the two chains, invalidating everything that happened on the shorter chain since the split.

so this means the transactions that the shorter version of blockchain have will become cancelled?

[DannyHamilton]

If two parts of the world become disconnected for whatever reason, each fragment will continue operating on its own fork of the blockchain. Once these parts have reconnected, clients will automatically accept the longest of the two chains, invalidating everything that happened on the shorter chain since the split.

so this means the transactions that the shorter version of blockchain have will become cancelled?

Many will.  Yes.

Any transaction that can trace any of its history back to block rewards that occurred in the orphaned chain will cease to exist as valid transations.

Transactions that are completely funded from block rewards that occurred prior to the split will simply become unconfirmed and be added back to the memory pool to be re-confirmed, unless any user in the forked chain transaction history leading up to that transaction happened to have somehow created transactions using the same unspent output from before the fork in both forks.

[alp]

If two parts of the world become disconnected for whatever reason, each fragment will continue operating on its own fork of the blockchain. Once these parts have reconnected, clients will automatically accept the longest of the two chains, invalidating everything that happened on the shorter chain since the split.

so this means the transactions that the shorter version of blockchain have will become cancelled?

Many will.  Yes.

Any transaction that can trace any of its history back to block rewards that occurred in the orphaned chain will cease to exist as valid transations.

Transactions that are completely funded from block rewards that occurred prior to the split will simply become unconfirmed and be added back to the memory pool to be re-confirmed, unless any user in the forked chain transaction history leading up to that transaction happened to have somehow created transactions using the same unspent output from before the fork in both forks.

Given that it's a disconnected network, it's very unlikely someone cold double-spend in both forks.  Although you have a hugely confirmed transaction that now is not confirmed, it might be easier to try to double-spend it if you are prepared for the network coming back online.  It would be unlikely that you wouldn't notice the network getting knocked out for a huge part of the world, and it also would be easy to estimate if your side of the network is smaller or bigger based on how fast blocks are getting solved, so you would pretty much know not to trust your blockchain very quickly.

[Morbid]

maybe a hint for future developments to include main continental nodes status/health indicators into clients?