I did some very basic calculations on the speeds of UFO'S ; For instance ; at 2000mph = divided by 60 mins = 33.33 miles / min. by 60 secs = 0.56 miles/sec. 5000mph = divided by 60 mins. = 83.33 miles/min. by 60 secs. = 1.39 miles/sec 10,000mph = divided by 60 mins. =166 miles/min. by 60 secs. = 2.7 miles/sec. 50,000mph = divided by 60 mins. = 833.33 miles/min. by 60 secs. = 69.45 miles/sec. So we can see why they can seem to " blink out " . Because within one second these craft will have gone at least a half a mile. Plus I think this refutes this " another dimension theory " as to why they just blink out or just disappear. The most puzzling thing about all this ; is that ; nobody has bothered to do these simple calculations before. These simple calculations changes one's perspective . I know that I have ; or rather did have a thread ; with these calculations ;but before it was hijacked into this or that opinion ; my POINT of the thread was to argue against the theory that the reason they wink out or blink out was because they come and go from other dimensions. The calculations show that per/second ; even at the minimum is 0.56 miles per second ; now think about this as far as the ability to keep site of anything having this kind of acceleration. It challenges the mind ; to keep track of the object.