Large pale silver dome seen over a hill and also near the house of SE Nebraska farm.

On our way back from the end of our cow pasture, while bringing the milk cows in to the dairy barn area, we were startled to see a huge silvery dome over the top of a hill about two city blocks ahead -- we had just walked past there on our way out to get the cows, it wasn't there then.  
We were scared,shocked, in disbelief, wondering how and why we were looking at something we could only guess was a giant quonset building or some really strange building basically between us and the safety of the barns, house or whatever. 
I was terrified, but the cows skirted to the right of it and kept on going.  So did we, and in about a minute or two, it just was no longer there.  
Even though I didn't see more than the dome, I was frightened to the core of my being.  
Then, about a month later, the same thing could be seen just past our wind break northeast of our house.  
That is enough to "creep out" any ten year old.
((NUFOR Note:  Witness indicates that the date of the incident is approximate.  PD))