How can someone Visit for Zero Seconds?

I am slightly confused over this that it is possible for a person to visit your site for 0 seconds and have found out that it is how Google Analytics tracks Visitors.Because if the Visitor does not Make a second pageview or does not stay long enough for GA to track them it will be Defined as a 0 second Visit

But Zero Seconds is not possible

It is possible that a person visits your Site for about 3 seconds because with time in mind to hit the Browser back button or press Atl+left because they have not found what they are looking for. But Zero seconds is not really possible so how do you find a better way of tracking your visitors than Google Analytics or Sitemeter .I thought all statcounters were the same and gave these results as 0 seconds, because the visitor does not reload the page or have java script enabled until I tried Clicky Stats.

Clicky works faster meaning Better Quality Reports

Because Clicky works a little faster than Google Analytics , I can see that people are visiting my site for maybe 10 seconds which is much more believable than the 0 second visits that Google Analytics Reports .Clicky is Free and but has a Pro version for Advanced Stats. So if you are looking for a Visitor Tracking Alternative to Google Analytics why not try Clicky and see real Visitor Stats for your Website