Lightning Cheat Sheet - Level Basic

A very basic and overview which can solve your initial queries :

What is the Lightning Component Framework?

-> The Lightning Component framework is a UI framework for developing dynamic web apps for mobile and desktop devices.

-> It uses JavaScript on the client side and Apex on the server side.

Framework

-> The aura namespace contains components to simplify your app logic, and the ui namespace contains components for user interface elements like buttons and input fields

Visualforce and Lightning Comparison

-> Lightning components are client-side focused, making them more dynamic and mobile

friendly.

-> Visualforce components are page-centric and rely heavily on server calls.

-> Lightning components use Apex on the server side, organizations that can’t use Apex code can’t create Lightning components, but they can use Visualforce

Benefits 

-> You don't have to spend your time optimizing your apps for different devices as the components take care of that for you.

-> Uses a stateful client and stateless server architecture that relies on JavaScript on the client side to manage UI component metadata and application data.

-> The framework uses JSON to exchange data between the server and the client.

Lightning Component?

-> Components are the self-contained and reusable units of an app.

-> A component can contain other components, as well as HTML, CSS, JavaScript, or any other Web-enabled code.

Tools

-> You can use Developer Console to build lightning apps and components

Aura and Lightning?

-> Lightning components are based on the open source Aura framework available at https://github.com/forcedotcom/aura.

-> The Aura framework enables you to build apps completely independent of your data in Salesforce.

Many more to come to get you started with lightning, stay tuned.

Cheers!!