On Sunday night, 6-11-17, I was observing the sky while on vacation at 11:00pm. I was looking directly overhead when a green light appeared on the eastern horizon. At first I thought it was a shooting star because it disappeared but reappeared an instant later and disappeared again. This object continued to do this as it traveled from one horizon to the other. The distance was covered in about 3 seconds. There was no sound. I could tell that it was at a high altitude. I thought it could have been a meteror bouncing off the atmosphere but it could not have been because it had very defined straight lines in the shape of a rectangle. Inside the rectangle was a black straight line. This object covered thousands of miles in a matter of seconds.