Forking Q1 - orphaned blocks

[Jet Cash]

I'm having difficulty in understanding the full complexity of blockchain forking. Most explanations seem to incorporate a variety of problems and descriptions, and this is making it difficult for me to understand. With your tolerance, I would like to ask a number of questions about specific forking issues, and I hope this will allow me to build a clearer picture of the issues. This first question is the relatively minor issue of orphaned blocks.

Sometimes a couple of miners will find a new block at virtually the same time. They both add these blocks to the chain, and this creates a chain with two "heads" but the same tail. As other miners find blocks they add their blocks to one of the heads, and this locks the direction of the chain if it becomes the longest. The other head ( and any blocks following it) are left out in the cold, and are described as orphaned blocks. Is this description correct? This leads to another question - what happens to those blocks? Are they discarded, which means the miner loses the revenue from his PoW, or can the miner re-use them and add them to the new longest chain? What happens to the transactions in them? Do they go back into the pool, and what if some have been included in new blocks? ( is this possible? ).

[AliceWonderMiscreations]

The orphaned blocks are worthless, ignored by the network, as if they never happened.

It might be possible for the miner or a team of miners to keep using them hoping to make that chain once again longer but unless those miners have 51% of the network hash rate, it becomes more and more unlikely they will be able with each additional block added to the chain that won.

[odolvlobo]

Your description is correct. Orphaned blocks are forgotten. The miner ends up not being paid for the block because the transaction in the block that pays him (the "coinbase" transaction) is not in a block in the chain. Transactions in the orphaned block are also included in the other blocks, so orphaned blocks have no impact on transactions.

[Jet Cash]

Why can't the miner use the PoW for the orphaned block to create a completely new block to add to the current longest chain? If that PoW hasn't been used in the current chain, then surely it can be retried.

[shorena]

Why can't the miner use the PoW for the orphaned block to create a completely new block to add to the current longest chain? If that PoW hasn't been used in the current chain, then surely it can be retried.

Part of the data that is hashed in order to find a valid block is the reference to the previous block in the chain. If you change that in an orphaned block the hash is different and very likely no longer valid (in terms of difficulty).

[Jet Cash]

Why can't the miner use the PoW for the orphaned block to create a completely new block to add to the current longest chain? If that PoW hasn't been used in the current chain, then surely it can be retried.

Part of the data that is hashed in order to find a valid block is the reference to the previous block in the chain. If you change that in an orphaned block the hash is different and very likely no longer valid (in terms of difficulty).

Thanks for that explanation. I think I understand now. Bit of a bummer to do all that work and lose it because you were a micro-second too late, but I guess that's life.

[AliceWonderMiscreations]

Why can't the miner use the PoW for the orphaned block to create a completely new block to add to the current longest chain? If that PoW hasn't been used in the current chain, then surely it can be retried.

Part of the data that is hashed in order to find a valid block is the reference to the previous block in the chain. If you change that in an orphaned block the hash is different and very likely no longer valid (in terms of difficulty).

Thanks for that explanation. I think I understand now. Bit of a bummer to do all that work and lose it because you were a micro-second too late, but I guess that's life.

It's really the only way non-centralized mining can work.

And being a micro-second two late doesn't mean your block won't get used, it really only depends upon which of the blocks the next block chose.

So you can solve the block after I solved the block but because the miner to solve the next block didn't get my block but got yours instead, yours is the one the network chooses.

Just like real mining, some like is always involved,