About block 12,103
Bitcoin block 12,103 was mined by Unknown on April 24, 2009 at 8:33 PM UTC, 17 min 46 s after block 12,102. That is slower than the 10-minute target; long gaps are normal, since every hash attempt is an independent draw with the same tiny chance.
It confirmed 1 transactions in 0.00 MB (0.0% of the 4 million weight-unit limit). The median transaction paid 0.00 sat/vB, and all fees added up to 0.0000 BTC. With the 50.000 BTC subsidy of halving era 1, Unknown earned 50.0000 BTC for this block.
Block 12,103 is number 8 of 2,016 in difficulty epoch 6; 2,008 blocks remain until the next difficulty adjustment at block 14,111. The next halving is at block 210,000, 197,897 blocks after this one.
Its hash starts with 8 zeros: that is the proof of work, a number below the target that the whole network’s hashrate had to search for. Unknown found 3 blocks in the week before. Today the block has 963,537 confirmations, so it is settled beyond any practical doubt.