<p>The design of the blockchain is such that such a scenario is not possible. By definition, the genesis block does not have an ancestor block. While it has a field for the previous block hash, this field is set to all 0's to indicate it is <code>null</code> and has no value set. This means that there are no blocks that come before the genesis block.</p>
<p>Additionally the genesis block is special in that it is both treated specially and hard coded into software. Nodes do not download the genesis block - they have the block in its entirety written into the software itself. This gives the genesis block special treatment, with one such special treatment being that the view of the blockchain is instantiated with the genesis block as the very first block.</p>
<hr />
<p>While it is most certainly possible (and probable) that blocks were created before the genesis block, these blocks would have been ones that Satoshi created during testing and belong to a different blockchain. Those would not be valid on the Bitcoin blockchain because they refer to their own genesis block, or are their own genesis block. The actual time they were created does not matter, only whether they refer to blocks which eventually refer to Bitcoin's genesis block.</p>

CC BY-SA 4.0
2021-03-16T08:36:41.880Z
I thought I red somewhere that the genesis block didn't have all zero's so that it could be a backdoor if Satoshi fabricated the hash form previous blocks. I wouldn't consider hardcoding it from being downloaded as impossible because it doesn't make it computational impossible where the all zero's hash does. The difficulty would simply be to large.
Wouter
CC BY-SA 4.0
2021-03-16T09:41:50.060Z
@Wouter You can see the genesis block here: https://en.bitcoin.it/wiki/Genesis_block It does contain all zeroes for the previous block.
Polygnome
CC BY-SA 4.0
2021-03-16T01:14:41.240Z
2021-03-16T01:14:41.240Z
Ava Chow
<p>How do we know that there are no blocks that predate the genesis block? A block that could potentially contain any number of coins. If somebody already created such a block from before the genesis but never published it could it (technically) stil be merged with the chain?</p>

<blockchain><genesis-block>
Blocks from before the genesis block
Wouter
# Blocks from before the genesis block

(Asked by: username_0 on 2021-03-16)

How do we know that there are no blocks that predate the genesis block? A block that could potentially contain any number of coins. If somebody already created such a block from before the genesis but never published it could it (technically) stil be merged with the chain?

**Tags:** blockchain, genesis-block


---

## 1 answers

### Answer by username_1 on 2021-03-16. Score: 7 | Accepted answer

The design of the blockchain is such that such a scenario is not possible. By definition, the genesis block does not have an ancestor block. While it has a field for the previous block hash, this field is set to all 0's to indicate it is `null` and has no value set. This means that there are no blocks that come before the genesis block.

Additionally the genesis block is special in that it is both treated specially and hard coded into software. Nodes do not download the genesis block - they have the block in its entirety written into the software itself. This gives the genesis block special treatment, with one such special treatment being that the view of the blockchain is instantiated with the genesis block as the very first block.

---

While it is most certainly possible (and probable) that blocks were created before the genesis block, these blocks would have been ones that Satoshi created during testing and belong to a different blockchain. Those would not be valid on the Bitcoin blockchain because they refer to their own genesis block, or are their own genesis block. The actual time they were created does not matter, only whether they refer to blocks which eventually refer to Bitcoin's genesis block.

> **Comments:**
> **username_0**: I thought I red somewhere that the genesis block didn't have all zero's so that it could be a backdoor if Satoshi fabricated the hash form previous blocks. I wouldn't consider hardcoding it from being downloaded as impossible because it doesn't make it computational impossible where the all zero's hash does. The difficulty would simply be to large.  
> **username_2**: @username_0 You can see the genesis block here: https://en.bitcoin.it/wiki/Genesis_block It does contain all zeroes for the previous block.  

---

