Large, bright light with no sound moved slowly over the Flathead Valley, MT towards the southeast, dimmed and vanished .The light was bright and flying lower than a satellite. There was no sound associated with the unidentified flying object. The light was flying at about the same height as a jetliner would fly. It was flying from the northwest to the southeast. As it approached the Swan Mountain Range to the east of the Flathead Valley, MT it vanished. I saw the object first and brought it to my roommate's attention. He came out to see it for himself and we both saw it vanish. Neither of us have ever seen an object like this before.