- They both get appended to the blockchain creating a fork
- A stale block is a block that has been “confirmed” at the same time as another but is then rejected and the transactions are sent back to the mempool
- This occurs because, when the chain forks, both blocks are available to have new blocks added to them; however, the chain with the block that is added to first is the one that is accepted and continued because the network selects the longest chain with the most POW. Therefore the block in the alternate chain must be dropped
- If you wish to be confident that your block has been confirmed, you must be sure that other blocks are linking to it. The more blocks that are linking to it, the more confident you can be that your block won’t be dropped due to forking
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- Both produce valid blocks that will go to the nodes, but only one will be adopted by the network, one that creates the longest chain.
- Stale block is a valid block but has been dropped by the network.
- When the network chooses the block in the longer chain that got adopted by more nodes it rejects the competing block on the shorter chain as it’s redundant.
- Several confirmations means there’s less of a chance of ending up in a stale block and having your transaction go back to the mempool.
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There are two different versions of the blockchain. The chain that is chosen is the one that has another block appended first (whichever is longer).
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A stale block is a block that gets dropped from the blockchain, including all the transactions that were in it.
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A stale block occurs when blocks are dropped from the blockchain. These blocks are dropped because their version of the blockchain was outdated in that another version already has more blocks appended to it.
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There is always the possibility that the block that your transaction takes place in will become a stale block. Waiting for six blocks after your transaction ensures that you are in the one true blockchain that is propagated through the global network.
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Sry forgot to answer the question. I’m a truck driver and do a lot of this in between getting loaded or unloaded. At the end of my day I’m pretty tired. Anyway I digress.
To the question you need to wait for more than one block in case there was a stale block. If you confirm to early and it was a stale block it could be that block that gets dropped from the network. I hope that I explained that correctly.
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- The chain is temporarily split into two possible outcomes
- A block whose transactions get returned to the mempool because it met a chain that had greater proof of work.
- Stale blocks are a result of the network dropping the block that belonged to the ‘losing’ chain or the chain that had the least proof of work.
- Because the block with your transaction could ultimately be rejected by the network. Waiting 6 block confirmations assures that your transaction is not orphaned.
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- What happens in the bitcoin network when two miners solve a block at the same time?
One of the blocks will get rejected (the shortest chain) and the tx will be sent back to the mempool.
- What is a stale block?
A completely valid block that gets dropped because it was not on the longest chain and the txs in that blocks goes back to the mempool
- How do stale blocks occur?
When miners mine a block at the same time but one of the block does not get added to the blockchain
- Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
To ensure that your transaction has been included in a confirmed version of the blockchain. After 6 conformations, there is no longer any risk that your tx ended up in a stale block and was returned to the mempool.
- The chain forks, and depending on where the next miner places their block, the longest chain stays and the other block is discarded (stale/orphaned)
- Stale block was dropped from blockchain due to a fork, and being in the shorter end. All transactions are returned to mempool
- If two miners append a block at the same time, the next miner picks one end of the fork based on what his side of the blockchain says. Then the block on the other (shorter) end of the fork gets discarded.
4.If you don’t wait, you run the risk of your block becoming stale and transactions being returned to the mempool
1.) Of the two blocks the one that is selected next by a valid miner and used for the next block will be longer and the other block will be orphaned.
2.). A Stale block, or orphaned block, is a block that was not used in the block chain for on.
3.) Stale block occur when one of two simultaneously created blocks is used to continue the blockchain. The resultant unused is released as stale, or orphaned.
4.) One should wait for 6 blocks because theoretically the double valid block could occur consecutively more than twice and if your transaction is laced into an orphaned chain it will need to be repacked up and added to the blockchain in a later evolution of the blockchain.
??? Is this why it makes no sense to buy a mining rig and look for the lower fee transactions? Because they will become orphaned as they are not in the hardest puzzle?
Wow. Amazing answers! Great job! 
Hi there! Actually, both blocks can be completely different, as each miner could have chosen different transactions to be processed. The block is drop not because its redundant, but because there is a blockchain with more proof of work (larger chain with more blocks).
- A fork in the Chain
- A Block that has been returned to the MemPool
- If a fork occurs in a Blockchain, the shorter of the two forks is droped and its Blocks are returned to
the MemPool. - To ensure the acceptance into the Blockchain.
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- What happens in the bitcoin network when two miners solve a block at the same time?
A: The longest blockchain becomes the confirmed/active block - What is a stale block?
A: A stale block is a block that has been mined at the same time as another one and that has been dropped from the chain in favor of another - How do stale blocks occur?
A: Stale blocks happen when two miners solve a block at the same time - Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
A: It’s important to wait for more than one block to be confirmed when sending or receiving a transaction because it takes time for all the nodes to get the updated version of the blockchain. If there was another valid block you have to wait and see which one gets added onto first thus making the slower one to be rejected by the nodes.
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- What happens in the bitcoin network when two miners solve a block at the same time?
When two miners solve a block at the same time, the one that gets propagated is the one that has the next block appended to it. The block on the shorter chain will be considered invalid and deleted off the blockchain. - What is a stale block?
A stale block is a block that has been added to the blockchain and subsequently dropped. - How do stale blocks occur?
Stale blocks occur when two miners complete the cryptography puzzle at the same time and get appended to the blockchain simultaneously creating two different versions of the blockchain. - Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
It is important to wait for more than one block to be confirmed when sending or receiving a transaction because it is possible for the block to be dropped as a stale block if subsequent blocks confirm another block before this one.
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What happens in the bitcoin network when two miners solve a block at the same time?
If two miners A and B solve the block at the same time then some miners will use block A for the next block and some will use block B. If the next block is found on top of B then block A will be orphaned and visa versa
What is a stale block?
The stale block is the chain that was discarded above when two blocks are found at roughly the same time.
How do stale blocks occur?
Network delays can cause two miners to find a block at roughly the same time. When this happens there are two versions of the truth and the miners must decide which to keep and which to discard. The longest chain wins here or the chain with the next block added to it the first.
Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
The larger the number of confirmations the more certain that the transaction was valid.
This prevents double spending.
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Orphaned blocks are mined blocks which have been dropped from the block chain.
A stale block is a block which was mined and put into a version of the blockchain but later dropped as it wasn’t added onto quick enough by another block.
Stale blocks occur when two different miners mine a block at the same time and then other miners add onto one of those blocks which will confirm which block will be part of the blockchain and which one will be returned to the mempool.
It important to wait longer than one confirmation for a transaction because two miners may have simultaneously mined a block and if your block isn’t the successful one added to the blockchain then that transaction will not be processed at that time and returned to the mempool to be done at a later time.
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- What happens in the bitcoin network when two miners solve a block at the same time?
The two blocks get propagated through the network at the same time and you have in that point in time two versions of truth because the nodes closer to one miner will accept one version of the new block and the nodes closer to the other miner will accept the other version of the new block.
- What is a stale block?
A stale block is a block that was once accepted in the blockchain by one part of the network but is later dropped as invalid.
- How do stale blocks occur?
Two blocks get accepted approximately at the same time and are propagated through the network creating two versions of truth. Then when the next block is created using one of them, the other will be invalid and will be called a stale block.
- Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
Because the transaction could be in a block that is in that moment considered the truth by some nodes but will be invalid and become a stale block in the future.
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- The longest blockchain will win and the other blockchain is rejected and dumped into the mempool.
- The block of the shortest chain after a fork, which is moved into the mempool.
- Stale blocks occur when there is a fork in the network due to two miners solving the problem at the same timewith different blocks and eventually network rejects the shortest block as new blocks have been mined without that in the other chain.
- It is important to wait for 6 confirmations to be sure that the block with your transactions is still in and not dropped from the chain.
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1. What happens in the bitcoin network when two miners solve a block at the same time?
If the blocks are valid the one that belongs to the longer chain wins. Sometimes it will be the one that propagates faster in the network.
2. What is a stale block?
Stale blocks are the ones that are dropped because an alternative longer chain exists.
3. How do stale blocks occur?
'Cause miners are competing so more than a valid block can be propagated in the bitcoin network. and it take time for a block to be full propagated in the network.
4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
Because the block that contains that transaction can be dropped, but statistically speaking after 6 blocks (around 60 minutes) you can be sure that the blockchain is consolidated so you can assume that the transaction in fully confirmed
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Thanks, wafflemaker. 
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