The ladder
| Depth | vs. Bitcoin's block 0 | Expected attempts | This forge's time |
|---|---|---|---|
| 00000000 | 1× (the original bar) | 4.3 billion | 21 milliseconds |
| 000000000 | 16× | 69 billion | a third of a second |
| 0000000000 | 256× | 1.1 trillion | about 6 seconds |
| 00000000000 | 4,096× | 17.6 trillion | about 90 seconds |
| 000000000000 | 65,536× | 281 trillion | about 23 minutes |
| 0000000000000 | ~1 million× | 4.5 quadrillion | ~6 hours |
| 00000000000000 | ~17 million× | 72 quadrillion | ~4 days |
| 0000000000000000000… | Bitcoin today | ~430 sextillion | ~68,000 years |
Times are averages on a GekkoScience Compac F (672 cores, ~200 billion hashes per second). Mining is a lottery, so a strike can land early or late; the averages are what the math promises over many tries. The forge strikes up to 12 zeros; the grey rungs are shown for scale.
Why zeros at all?
Mining means retrying a block with different nonce values until its hash falls below a target number. A tiny target is just a number that starts with a lot of zeros, so any hash below it must start with zeros too. That is the whole trick: the zeros at the front of a hash are impossible to fake and instant to check. Finding one takes billions of guesses. Verifying one takes a single hash, which your browser can do in a blink.
Why sixteen times per zero?
Hashes are written in hexadecimal, and each hex digit carries 4 bits. Requiring one more leading zero digit means 4 more bits must come up zero, and each bit doubles the search: 2 × 2 × 2 × 2 = 16×. That is why the ladder gets steep so fast; five extra zeros is not five times harder, it is a million times harder.
How the forge searches deeper
The chip never changes. It always sweeps all 4.3 billion nonces of one header in about 21 milliseconds and reports its candidates. One header only contains a deeper solution once in a great while, so the forge rolls the block's timestamp on every task, handing the chip a fresh universe to search every tenth of a second. Depth is patience, not a different machine.
Its difficulty only required eight. The extra two were luck, frozen forever.
Where the real chain is today
Bitcoin's network difficulty has climbed for seventeen years; today's blocks need roughly 19 to 20 leading zeros. At that depth this entire forge would average one block every 68,000 years, which is why modern mining is warehouses, not USB sticks. The vault here works at the original 2009 bar and above it, where a single small chip can still climb the ladder while you watch.