A flash of neon green light "opened up" and remained opened for 5-6 seconds. It made no sound, and two seconds later, we heard a plane come out of the same area. From our experiences, it sounded military.Myself, mother-in-law and family member were driving back from Kayenta, AZ (20 miles away). We were driving back down into the Valley where our family lives (Navajo Reservation). As we were passingThe Mittens (rock formations), to the left of us (North-East) a bright flash of neon green light seemed to open up, with no sound at all. We IMMEDIATELY stopped to watch, and it remained opened. Streakes of green white light were coming out of it. Like lightening. It closed without a sound, which made all three of us so very uncomfortable. We then heard a military jet streaking across the sky at very low altitude. It appeared out of no where. We were all so stunned, we couldnt move for 10 minutes. We were afraid to move. If someone was to ask me what it reminded me of, it reminded me of the worm hole on Deep Space Nine. It mimicked that "opening up" and "closing". When we finally got home, we told our father about it. He is a Navajo medicine man. He said he has seen that event a couple of times. He was not surprised.