Beacon Chain vs. Relay Chain
While Ethereum 2.0 and Polkadot are both sharded networks, there is a slight difference in how they work. Ethereum 2.0 uses a Beacon Chain into which different parallel shards plug into for sharing of information. Only shards with the right structure can connect to the Beacon Chain.
Polkadot uses a Relay Chain to connect different shards (parachains). Each parachain operates independently. However, Polkadot’s Relay Chain is more flexible than Beacon Chain in the way it accepts shards. Each shard (parachain) makes its own rules (Meta Protocol). The Relay Chain accepts different parachains, which are executed by Relay Chain Validators using standard WebAssembly allowing for higher interoperability than Beacon Chain. External chains connect to Polkadot’s Ecosystem using bridged chains.
In effect, applications from Ethereum 2.0 can connect to Polkadot’s Ecosystem, but Polkadot apps cannot connect to Ethereum 2.0. This is because Ethereum 2.0’s Beacon Chain does not offer bridging for decentralised apps (dApps) developed outside the Ethereum ecosystem, as Polkadot’s Relay Chain does.
A good example of an Ethereum-based bridged parachain is the Moonbeam, which allows Ethereum 2.0 apps to run in Polkadot’s Ecosystem. There is also news that there will be wrapped Bitcoin parachain. It will enable users to mint 1:1 Bitcoin-backed assets onto Polkadot as PolkaBTC, which can be used for including decentralised exchanges, stable coins, and lending protocols.