I don't understand the loops with different Hash but same block number @ http://status.ethereum.org/. Are they Uncles?

1 Answer 1


Yes, they're uncle blocks.

To confirm, you can check against the list of known uncle blocks on EtherScan - https://etherscan.io/uncles.

  • Thanks Richard. Can you explain why they link back into the main chain at different points, sometimes the next block but sometimes further along?
    – Prof_Alex
    Commented Dec 15, 2017 at 9:37
  • 1
    When a block is orphaned/uncled, it's not the end of the story. To claw back some of the hash power used in finding the PoW for the orphaned block, it can be included back into the main/canonical chain as part of a later block. (I think it's incorporated into the "Ommers list" part of the block header.) Hence the looping back to the main chain: it indicates into which later block the uncle was incorporated. (Have a look at the GHOST protocol: ethereum.stackexchange.com/questions/314/…) Commented Dec 15, 2017 at 10:39

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