Re: What determines the number of tx that can fit into a block?
⭐ Merited by LoyceV (6) ,ABCbits (4) ,Felicity_Tide (1) ,vapourminer (1) ,mcdouglasx (1) ,DdmrDdmr (1)
Ah, you're from the post segwit age 
Blocks used to have a maximum size of 1Mb, but since blocks were always full and fees were high (iirc, that was the reason), there was a big discussion on how to solve this issue. A fork with bigger blocks was made (bitcoin cash) but it didn't gain tracktion.
What did gain traction was segwit: SEGgregated WITness. Basically, transaction data was still limited to 1Mb, but witness data (basically, the signature) was moved to the end of the block, and no longer counted to this 1Mb limit (there is a limit for witness data aswell, but afaik, it's very seldomly reached due to the existing limit of 1Mb for the actual transaction data).
Why did we do it this way? Because new segwit transactions were formed in such a way that pre-segwit nodes still saw these transactions as valid transactions, eventough they had a 1Mb block limit, so they basically "ignored" the witness data. Post segwit nodes saw the transaction data AND the witness data, and basically verified the signature aswell... That way, we could have a soft fork and still increase the capacity of the block.
Blocks used to have a maximum size of 1Mb, but since blocks were always full and fees were high (iirc, that was the reason), there was a big discussion on how to solve this issue. A fork with bigger blocks was made (bitcoin cash) but it didn't gain tracktion.
What did gain traction was segwit: SEGgregated WITness. Basically, transaction data was still limited to 1Mb, but witness data (basically, the signature) was moved to the end of the block, and no longer counted to this 1Mb limit (there is a limit for witness data aswell, but afaik, it's very seldomly reached due to the existing limit of 1Mb for the actual transaction data).
Why did we do it this way? Because new segwit transactions were formed in such a way that pre-segwit nodes still saw these transactions as valid transactions, eventough they had a 1Mb block limit, so they basically "ignored" the witness data. Post segwit nodes saw the transaction data AND the witness data, and basically verified the signature aswell... That way, we could have a soft fork and still increase the capacity of the block.