According to the data stored in the blockchain, the genesis block is mined at Jan 03, 2009. The second block is mined at Jan 09, 2009, 6:24:25 AM. Which is 6 days later. At first, it seems rational to me, because at that time, the only one who was running a node was Satoshi, and even if the difficulty was very low, mining by one machine was very time consuming. By this reasoning, I expected the mining of first 2016 blocks would take time at this magnitude (Because after the 2016 blocks the difficulty would be readjusted and set to a lower level, though I'm not sure it can be less than 1 or not). But next blocks are mined very faster.
- Height 0: Jan 03, 2009, 9:45:05 PM
- Height 1: Jan 09, 2009, 6:24:25 AM
- Height 2: Jan 09, 2009, 6:25:44 AM
- Height 3: Jan 09, 2009, 6:32:53 AM
- Height 4: Jan 09, 2009, 6:46:28 AM
The difficulty of network was the same for all these blocks. What is the reason for this variation? Was there a jump in the number of miners at that time?