I was outside sky watching like I do from time to time and not having any luck lately, when all of a sudden I noticed a moving object. Thinking it was a plane because I live near an airport and see planes quite frequently I didn't think much of it. However, I noticed it was pulsating and seemed to be changing colors from white to green, not entirely sure though but it seemed too. There were no aviation lights, no sound and it traveled across the sky for about ten minutes until it went out of view entirely. It moved pretty slow. I have seen objects such as this before, but never witnessing it this long. I was completely fascinated and couldn't take my eyes off of it. It was a very weird situation! I tried to take a picture with my cell phone but it was too dark to see anything unfortunately. Hopefully one day I will be able to get a picture of one of these objects.