Chaos Signals to Decide Blockchains?

Question

Bitcoins require many gigawatts of electricity for mining, and so does the blockchain.

Aren't there much cheaper alternatives to solving mathematical equations, which use chaos?

For example, Sunspot patterns are a fingerprint of chaos and globally verifiable. If everyone on the chain uploads a 50kb cellphone photo twice a day... The total of that data would have the unpredictability of physical chaos. Isn't there a convenient chaos signal which is globally verifiable and which is better for allocating money and tasks than mining?

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Apologies for being vague. I will try to clarify:

peer money and accounts nodes can be given a lottery ticket number as a pseudo random function based on a previous chaos result, ranging from 0 to 10^256.

Every hour the miners of the world return their collective measurement of a globally generated chaos signals, which returns a random number from 0 to 10^256, and the closest miner's ticket is recognized by all as the winner.

The winner gives his version of unverified transactions including transaction times and the time corresponding to the block challenge in a hash which includes sha-256 of all the previous blocks that have been tallied.

It would help me to understand hash contests, to know why the digital encryption wouldn't benefit from simply choosing a miner at random using tallied measurements of chaos from the cosmos or from global weather and so forth.

Answer 1

The main issue with choosing a miner "at random" is finding a verifiable public source for randomness. Most public randomness sources run through a centralized party, which is no good for Bitcoin, where everything needs to be cryptographically verifiable.

There have been some attempts at a public, verifiable randomness source in Bitcoin, but given that the system is eventually consistent and subject to collusion, it's been shown to be difficult. See "On Bitcoin as a public randomness source" and "Proofs-of-delay and randomness beacons in Ethereum".

Another possible way to avoid the issue of excessive energy consumption is Proof-of-Stake-based blockchains. Instead of creating a computational marketplace (which in Bitcoin is very competitive) to verify blocks, proof-of-stake uses staking of coins to decide what the next block is. You earn a block reward by committing money to a certain block. There are chain-based approaches (Peercoin and Blackcoin) and BFT-based approaches (Casper and Tendermint). Here's a good intro guide to PoS and Ethereum's Casper.