i've said this is what we've been hearing for years,the fact that it is from U2s,but i myself couldn't explain why.people around these parts can hear an odd sound at night (mostly) that many have claimed to be "space craft",people like my brother inlaw,anyway..it is when a U2 is setting up to land at Beale,Juan says they start doing this at the Mustang VOR.anyway,,watch its interresting.