Bitcoin Forum

Bitcoin's consensus takes the longest chain and occasionally there can be more than one blocks mined at the same time, causing a temporary fork. My question is, how often does this situation happen? and how close is the gap between the first and the second, say, if miners continue to mine the block after the first block is announced, how long does it take for the second miner to announce the block?

Both finding at the same time...I assume you mean plus or minus 1 second since time can be more or less divided infinitely. The one who gets consensus first wins - hence the bullying worry of 51% pools.

If you mean "at the same time" that two miners present possible solutions for the current block then this happens all the time and causes one of the blocks to become an "orphaned block".  The miner that mines the block containing the most work automatically wins and the miner who mined the block with less work gets the shaft (no reward).

Statistic here:

https://blockchain.info/charts/n-orphaned-blocks

I found a real cool view of this phenomenon:

https://blockchain.info/orphaned-blocks

That is a lot of blocks! Thanks for sharing this information.

This has sparkled me a new question: what will happen if Bitcoin changes its incentive to not the only awarding the first miner, but top N miners who broadcast their blocks, each gets a share according to their chronologoical order? Like 1st gets 50%, 2nd gets 25%, 3rd gets 12.5%, etc

The Bitcoin protocol is almost impossible to change, so the quick answer to your question is that this will never change.

If you could change the protocol a better change would be to reward full nodes for operating on the network.  Currently people (like me) that operate full nodes get no compensation at all so the number of full nodes operating continues to shrink.

But, like I said the Bitcoin protocol is almost impossible to change since pretty much everyone has to agree to any change.

A longer answer is that the miners consider orphaned blocks part of their "cost of doing business".  Every miner gets a percentage of the orphaned blocks so the pain is spread out among the miners.  Orphaned blocks are just a fact of life for the miners.  I do not want to get into all this but the orphaned block rate figures into the whole controversy related to raising the block size.

Raising the block size is an example of a change to the protocol that has been proposed and debated for months and months in hundreds of threads here on this forum and there is still no consensus on how to move forward on this one single change to the protocol.

By design changing the protocol is very very hard to do.