Lets see what we do not know about Space:
- The world is flat. At least for most every aspect of our life this is a fact.
- What we perceive as "things" is nothing but tiny conglomerations of energy within space, manifesting as matter. We do not know what matter actually is. We do not know what gravity is, except that it has to do something with matter - which we do not understand.
- Space seems to be where nothing is. But that is not true - space is full of background emission (I like the german term Grundrauschen much better).
Moving in Space
We move in space. ISO 19116 specifies: "Motion is the rate of change in positional relationship (translation) between two spatial reference systems: one associated with the object of interest such as a vehicle, and one associated with a reference body such as the Earth."
Cosmic Microwave Background Radiation
Space is not empty of everything (void). Instead it is filled with a Cosmic Microwave Background Radiation (in German Hintergrundstrahlung). For many years this has been attributed to some quirk but slowly a new understanding is emerging making sense of this unique phenomenon. Unlike gravity (which is another inexplicable phenomenon) Cosmic Background Radiation seems to be evenly spread throughout space. Every cubic centimeter of vacuum in outer space contains approximately 400 photons of a Cosmic Microwave Background Radiation.