The Bitcoin mempool is a temporary storage for unconfirmed transactions waiting to be verified by the Bitcoin network. When a transaction is initiated, it enters the mempool until miners include it in a new blockchain block. Each Bitcoin block has a size limit*, meaning only a certain number of transactions can be included in a single block. The mempool's size can provide insights into transaction demand and the current fee market.

"Mempool clearance" describes how quickly transactions are confirmed and removed from the mempool. If the mempool clears quickly, it means miners are confirming transactions faster than new ones are arriving. However, if transactions accumulate faster than they're processed, the mempool grows, leading to potential delays.

*Each Bitcoin block has a size limit traditionally set at 1 MB, but with the SegWit upgrade, this changed to a virtual size or "vMB" with an effective limit that can go up to approximately 4 MB depending on the transaction types.

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The last time the Bitcoin mempool was completely cleared on April 20, 2023. Since then, there are always transactions in the queue.

This market will resolve to YES, if before block #840,000 the Mempool size falls below 1vMB, as indicated by the Coinmetrics' resolution source.