Proof-Of-Work is a Decentralized Clock
I think some of this is kind of wrong.<p>Mostly the claim that &quot;The Difficulty is Intergalactic&quot; is just flat wrong.
Consider a miner on mars with 10% of the hash-rate on earth. Lets say the light delay from earth to mars is 10 minutes (it is 14 on average).<p>Now, suppose mars has last seen block B_0 and it was mined on earth (as would happen most often due to 90% of the hash rate being there). We will call E_1 the next block found if only earth were to mine, and M_1 the block for mars.
Now, mars has two really big dis-advantages. First of all, earth gets to see B_0 ten minutes before mars does. So, earth can start mining a lot earlier.
Second of all, when mars does find a block, but earth finds a block 10 minutes later, earth is going to orphan the martian block.<p>So, if mars has fewer than 20 minutes of advantage over earth, there is a very good chance any block they find won&#x27;t matter.<p>Now, I suppose if the hash-rate is more spread-out over multiple planets, and one planet isn&#x27;t dominating things might work out. But we might also see consensus break down. I might sit down and do the rigorous math on that tommorow, just to see what happens.<p>(Other minor nitpicks)<p>&gt; SHA is Memoryless and Progress-Free<p>Technically false, because memory-less processes have positive probabilty of yielding no block after 2^256 tries, whereas for sha-256 using brute force, this probability is totally 0.
I don&#x27;t think this matters at the current hash-rate though. (our current hashrate covers about (2.5 * 10^-53)% of the entire output space every 10 minutes.)<p>&gt; Trying a SHA Makes You a Participant<p>Only if you would actually submit your hash if you found a match. The same holds for the prime-factorization example. If I happen to factor a huge number and tell no-one I haven&#x27;t contributed.