Historical Difficulty?

[BTC Economist]

Does anyone have historical difficulty number and can someone explain what a difficulty number means?

[1715478769]

1715478769

[1715478769]

1715478769

[1715478769]

1715478769

[deepceleron]

http://bitcoin.sipa.be/

and

http://en.bitcoin.it/wiki/Difficulty

[jollyjim]

https://spreadsheets.google.com/pub?hl=en&hl=en&key=0AmcTCtjBoRWUdHVRMHpqWUJValI1RlZiaEtCT1RrQmc

[cuongnq]

https://spreadsheets.google.com/pub?hl=en&hl=en&key=0AmcTCtjBoRWUdHVRMHpqWUJValI1RlZiaEtCT1RrQmc

What happening if diff too high

[jollyjim]

The higher the difficulty, the longer it'll take for you to mine.  The recent 57% jump in difficulty means you'll average out to making 1/1.57 = 0.636 of what you were making before.  So if you were making 1.0 BTC yesterday, today you'll be making 0.636 BTC in the same amount of time (disregarding variance).

[jollyjim]

And in about 10 days, if the difficulty jumps up another 50%, it'll reduce that 0.636 BTC down by a factor of 1/1.5 = 0.666, which would make it 0.4236 BTC.  10 days after that, another 50% jump would reduce it to 0.2821 BTC, then 0.1879 BTC, etc.  This is why you should never estimate earnings with no difficulty increases.  50% increases every 10 days is a lot but it hasn't really been letting up.  33% increases every 10 days is probably more reasonable but even at that slower rate, BTC needs to be at least $30 to possibly break even on new rigs.