Funky,
Of course the universe can be measured. Not accurately, perhaps but its size, age and mass can be estimated. And the effects of any part of the universe known to exist can be measured. Parts of the universe not known to exist can be tested for. It's the fact that it exists and affects us that makes it measurable.
I think that Max Planck said that we can never fully understand the universe is because we are part of it. Quantum physics has uncertainty built into it because we are limited to our ability know.
As for man understanding and measuring the universe these are just mathematical estimations that can and will be adjusted. To accurately know and measure the universe or even little parts of it is an impossiblity. Clasical physics used to think that they would soon have all the answers, but then Einstien came on the seen with "relativity" and changed forever our view of the world. Absolute knowledge of the universe or measurement is an impossiblity. Even Hawkings hope for "theory of everything" is a misnomer, that is merely mathimatical with no way of testing, because we are part of the universe and can never duplicate by means of experiment, or test to prove a theory of everything when one is finally made. We can only measure relatively never accurately, we can only estimate.
If we could some how climb out of the physical universe then perhaps we could measure it.