Block number and time in Ethereum are closely related. The Ethereum blockchain is a distributed ledger that records all transactions that occur on the network. Each transaction is recorded in a block, which is identified by its block number. As more blocks are added to the chain, the block number increases.

Block time in Ethereum is the time between blocks, which is divided into 12-second units called 'slots'. In each slot, a single validator is selected to propose a block. As long as all validators are online and functioning, there will be a block in every slot, resulting in a block time of 12 seconds. However, if a validator is offline when it is called to propose a block, slots may go empty. This is different from proof-of-work based systems, where block times are probabilistic and adjusted by the protocol's target mining difficulty.Ethereum's average block time of 12 seconds reflects the transition from proof-of-work to proof-of-stake.

The block number is directly related to the amount of time that has passed since the Ethereum network was launched. For example, the first block in the Ethereum blockchain, known as the Genesis block, has a block number of 0. This means that the Ethereum network was launched 0 blocks ago. As more blocks are added to the chain, the block number increases, and the amount of time that has passed since the launch of the network also increases.