Expert: Tom Whiting - 1/12/2009

Question
Hi,

Me and my cuzin were walkin around the block and we seen this really big bright light hooving in the sky, it was just sitting there for 5 to 10mins then the light got smaller and smaller then just took off and disappeared. Do you know what that could of been. B.c me and my cuzin are like freaking out.

Answer
Hi Tanya,
Light (or lights) at night, especially low on the horizon, are very deceptive and very hard at times to determine. That's why I rarely respond to them.
In most cases they turn out to be either a far distant aircraft landing light left on (so at that distance of 50-100 miles,
there is no discernible motion. (Yes, on a clear night we can
see aircraft landing lights for nearly 100 miles out)!
Point meteors (one coming in head on to the observer) do the same, but of course, not for 5-10 minutes, usually only a couple of seconds, so that one is ruled out.
And in your case, the light got dimmer and dimmer, not smaller
and smaller...the human eye cannot determine size on a near-point
source of light. When we look at stars (which are trillions of miles
distant) we can't see size (diameter) we only see their brightness.
That's all that is determinable on a point source of light.

So an aircraft headlight coming nearly right toward you which the pilot eventually turned off, or turned away from you, is my best estimate for your observation. I've seen them many times out observing at night. But they don't 'freak out' us astronomers because we know what they are.  
Following Occam's Razor - the simplest explanation for competing theories is most likely the correct one - (that is, the one with
the fewest wild assumptions)... the explanation above is the best and
simplest one.
Hope this helps,
Clear Skies,
Tom Whiting
Erie, PA