Explain development of Ethereum 2.0 phase and how validators are affected in POS?

Ethereum 2.0, also known as Eth2 or "Serenity", is an upgrade to the Ethereum blockchain. This upgrade aims to enhance the speed, efficiency, and scalability of the Ethereum network, enabling it to process more transactions and ease congestion. The development of Ethereum 2.0 is divided into multiple phases:

1. Phase 0: This is the first phase of Ethereum 2.0 and is focused on the implementation of the Beacon Chain. The Beacon Chain is a Proof of Stake (PoS) blockchain that will run parallel to the existing Ethereum network. This phase was launched in December 2020.

2. Phase 1: This phase will introduce shard chains, which are smaller chains that run in parallel to the main Ethereum chain. This will significantly increase the capacity of the network. This phase is expected to be launched in 2021.

3. Phase 1.5: This phase will see the existing Ethereum network merge with the Beacon Chain, marking the end of Proof of Work (PoW) Ethereum and the full transition to PoS.

4. Phase 2: This is the final phase of Ethereum 2.0. It will add more functionality to the shard chains, including the ability to handle smart contracts.

In the PoS consensus mechanism, validators replace miners in the network. Validators are chosen to create a new block based on the amount of Ethereum they hold and are willing to 'stake' as collateral.

In Ethereum 2.0, validators are affected in several ways:

1. Becoming a validator requires a stake of 32 ETH. This is a significant investment, and it's locked up for a period of time. If a validator behaves dishonestly, they can lose a portion, or all, of their stake.

2. Validators are chosen at random to validate blocks. The more ETH a validator stakes, the higher the chance they have of being chosen.

3. Validators will earn rewards for validating blocks. These rewards come from the transaction fees of the blocks they validate and the annual issuance of new ETH.

4. Validators who are offline or fail to validate blocks will see their stake slowly decrease as a penalty. This is to ensure that validators stay online and actively participate in block validation.

In summary, Ethereum 2.0 introduces a new consensus mechanism that changes the role of validators and the way they interact with the network. Validators have a more active role in maintaining the network and are rewarded for their participation.