Silent Metallic Orange Orb silently hovering at low altitude over Denver

This was a metallic orange orb moving steadily and silently as low as 500 feet to over 2,000 feet above ground level from west to east, with gradual ascending and descending movements. It also appeared to either emit light or reflect sunlight irregularly, even though there was steady sunlight coming from the west. It was visible for many miles, and as it moved eastward it ascended to an altitude and location consistent with the routes flown by commercial and military aircraft in the Denver International Airport vicinity.