Time order of blocks

[dunkbc]

Just noticed on blockchain: block 351762  is older than block 351761 - what is going on ?

[DannyHamilton]

Just noticed on blockchain: block 351762  is older than block 351761 - what is going on ?

Timestamps on blocks are not exact.  Protocol allows the miner to adjust the timestamp a bit in case the clock on his computer doesn't EXACTLY match someone else's clock.  Therefore when two blocks happen quickly one after the other, sometimes the earlier block can have a later timestamp.

This isn't new.  It's always happened.  Not a big deal.  Protocol is designed to handle it just fine.  The order of the blocks determines the order of the transactions no matter what the timestamp says.

[dunkbc]

thanks danny;

[Dabs]

I think blocks have to be within a couple of hours of the "correct" time, which is an average or something of the most recent blocks. So if miners clocks are off by a few minutes, that's perfectly alright; but they can't be off by more than several hours or the rest of the network will simply reject the block.

In general, time moves forward in the blockchain.

[el kaka22]

I also seen some blocks like this (and I had seen some of those are 10 minutes older than the last block) and it is normal (because there are different system time in different miners, typically a difference of maximum 6 minutes in my experience).