Two sets of lights blinking alternately.

My friend and I were laying in my front yard looking at the stars.  We both grew silent and I observed what appeared to be two sets of lights alternately blinking.  These were in the northwestern sky about 100 feet above the ground and maybe 1/4 mile away.  After about 5 minutes, something prompted me to get in the house.  At the same time we both jumped up and ran inside.  We were 10 and 8 respectively.  I never knew how to describe it until I saw a similar video on the history channel.  In that video the craft was round with a row of lights around the middle.  There was the same alternate blinking of two sets of lights.