AetherCraft Mod refers to aether which is material not only to make up all objects you can see, but also binds together all matter.
Through this material, you might get more tools to convert items into pure Aether and turn Aether into items. Additionally, it allows you to use Aether to charge items of great power. As you see, this material is quite fantastic which you only see in theory before. Now, you have the tools to convert things to and from this ur-substance!