I am completely new to Ethereum. I read a lot of articles and have a question. As far as I understood, one can develop smart contracts in Ethereum that are like executable programs. In these programs one can make a transaction.
For example I want to send 5 Ether to Bob. This is a transaction. Now, I am going to develop a program that compiles on EVM and in this program I send 5 Ether to Bob.
Now my question: I can code anything I want. If I have only 5 Ether in my balance, but I am going to spend 500 Ether to Bob, who will read and check my code and decide how many Ether I can spend or not ? In Bitcoin nodes or miner can check the blockchain and look, how many Bitcoin you have spent and you still have.