The reason this outlet is open was because my washing machine was connected directly to it. I was advised to close it up by the people who took my old washing machine away. However i dont think i can wait until my friend has time to look at this. I likely cant turn the power on on the outlet at all right now i assume, how can i make sure myself that i can safely turn the power back on? electricity varies wildly in countries, im from austria if that helps.

Edit: a friend of mine who does some electrician work as part of his job (building pools) corroborated several of your comments (the only exposed cable is the grounding one and he offered to cover it up further at a later point after i put some tape on it)

thank you all for your answers and putting me at ease