Ethereum is a cryptocurrency, also called Ether, (abbreviated ETH), created on its own Blockchain that supports smart contracts, which in turn are executed using ethers as currency.
Who created Ethereum?
Ethereum was created in 2015 by Vitalik Buterin, who through the Ethereum organization manages the technological development of this cryptocurrency.
What is a smart contract?
It is an agreement, as it could be a promise of traditional sale, which is written as computer code in an immutable and inviolable database (a Blockchain), so it is not only a contract free of human interpretations, but it is also a contract that is not exposed to be altered or modified unilaterally.
Why is it necessary to pay ethers to execute a smart contract?
An intelligent contract is a software that requires the processor of a computer to be read and executed, and this in turn requires electricity and hardware to operate, so there is a real economic cost in processing an intelligent contract, and in the ecosystem of Ethereum the currency of exchange are the ethers / ETH.
And why do the ethers have value?
Given that the Ethers are scarce per protocol, if the Ethereum ecosystem becomes successful and the demand for ethers increases, a rise in price is the only mechanism the market has to strike a balance.