update block time

docs/protocol/network/epoch.md

@@ -12,10 +12,10 @@ This section explains the concept of an **epoch** in the NEAR Protocol, which is
 
 An **epoch** is a unit of time when validators of the network remain constant. It is measured in blocks:
 
-- Both `testnet` and `mainnet` have an epoch duration of 43,200 blocks. Ideally epochs last about 12 hours, since blocks are created every second (in reality, they take slightly longer to be created).
+- Both `testnet` and `mainnet` have an epoch duration of 43,200 blocks. Ideally epochs last 7.2 hours, since blocks are created every 0.6 seconds (in reality, they take slightly longer to be created).
 - You can view this setting by querying the **[`protocol_config`](/api/rpc/protocol#protocol-config)** RPC endpoint and searching for `epoch_length`.
 
-**Note:** Nodes garbage collect blocks after 5 epochs (~2.5 days) unless they are [archival nodes](https://near-nodes.io/intro/node-types#archival-node).
+**Note:** Nodes garbage collect blocks after 5 epochs (~1.5 days) unless they are [archival nodes](https://near-nodes.io/intro/node-types#archival-node).
 
 **Example:**