@Leadfoot,
I am pretty sure that you don't have the mathematical background to understand the Einstein field equations. Correct me if I am wrong.
When scientists talk about the expansion of space, they are referring to a feature of the Einstein field equations, particularly the Cosmological Constant. This is a well defined term that any graduate physics student knows backwards and forward. There are still debates in the field, but the concepts that are being debated are very well understood.
If you don't understand the Einstein field equation or know what the Cosmological Constant is, then how can you discuss this intelligently? You can pretend you understand the word expansion... but do you? If everything, including you and your eyes and all the trees and the atoms and every measuring stick in the world doubled in size overnight. How would you know? (This is actually a very silly exersize... but maybe it makes some point).
Sure, there are plenty of open question in science. There are papers being written about dark matter... and a lot of debate about what its properties might be. But this doesn't change the fact that the people who are capable of having this discussion all understand very well the basic precepts of General Relativity, and they all can explain very well what is meant by the expansion of space and how to set up experiments to measure it.
Scientists are the people who do science. They are the people who have studied the advanced math, who understand the work of Newton, and Galileo and Feynman and the other greats who came before them. They can explain the experiments and the arguments behind the current issues in science.
Science is about mathematics, and experiment, and understanding human knowledge that has been built up over thousands of years. You gain this knowledge by studying advanced mathematics, and reading papers, and analyzing experiments and learning about the work done by previous generations. You don't just make stuff up and call it science.
And you don't gain this knowledge from pulling random things off the internet.