I saw a green egg shaped object flying in the sky heading north.

I was sitting out in my backyard while my house cooled off so I could go to bed. I was in a lounge chair facing the east watching the planes come in from the east going to Seatac airport. Suddenly I noticed a green egg shaped object appear out of nowhere. It was directly in front of me traveling north towards Everett Wa. It was almost flourescent. I'd guess it was traveling about twice as fast as a typical plane would travel. It made no sound. I believe the object just manifested because I didn't see it off to my left as it entered from the south. I think I would have seen it. A possible debunk is maybe I was focused higher in the sky where the planes were because this object was flying below their flight path.
Tough to estimate size. Easily noticeable though. No blinking lights of any kind. It was just an a kind of illuminated green.