As a native of Columbus, Ohio, I have seen many things in the sky that looked strange but turned out to be manmade or natural things, like planets, planes viewed from odd angles, lenticular clouds, planets, etc. But I have never personally seen anything like this. I wear contacts which give me quite good distance viewing, but I need reading glasses for up close focusing. I was on vacation to Utah and then points south. After driving through much of Rocky Mountains (travelling west on I-70 I think, because I recall divided highway at time of the sighting), we emerged into a relatively flat area which had a mountain range running along the far left at some miles away and another to the left-front of car. This was about midday on April 28 or 29, 2013, with little or no clouds in the sky, no rain. I was alert, had no alchohol or drugs in my system and the last thing on my mind was an encounter with something unusual. Between my car and the left-front range was a small city (maybe Grand Junction, Colorado ?). Probably due to its motion, I happened to observe a metallic circle/sphere near the bottom of the left-front range, situated near the left-end of the range. It was travelling in a near-perfect straight line apparently from the bottom of the range toward the top of the range (apparently not far above treetops). I estimated the object and the range to be at least a couple of miles away (possibly several) due to the size of the city between us, and due to the fact that I could not really make out individual trees on the mountain (the mountainside was sunlit). I have been out to the southwest before and am aware that distances are frequently farther than they appear to native easterners. At first I thought this object was reflection from a helicopter bubble, a balloon, or some sort of ski lift that I was not familiar with, so I was not too concerned, and so unfortunately did not note any details such as specific time nor location. However, I kept watching. Diameter of the object was around 10 percent the height of the mountain. To my best recollection, the object rose from the near bottom of the mountain to its ridge in about 5 to 8 seconds after which it made a 90-degree right turn to follow the ridge for about 3 to 5 seconds. At this point it either just disappeared or dropped down the other side of the mountain (it was hard to tell which from my distance combined with car motion). Almost immediately after that, I saw what appeared to be the outline of a small jet with contrail shooting up from the other side of the mountain in a steep climb almost in line with where the object had made the 90 degree turn (it occurred to me later that it seemed like the sphere may have been "hiding" from or secretly observing the jet, but this is purely conjecture). During the observation I asked my driving companion if she saw the object but she could not see anything before the event had ended (I don't think her distance vision is as good as mine). I was rather preoccupied with getting to our next destination on our vacation, so I did not stop and take any photo or write down any details. At the time of observation, I was not feeling disturbed or upset but rather curious, skeptic and amazed. However, after I returned from vacation, I have been feeling rather disturbed about this recently, and very much reret not joting the details at the time. It only occurred to me later after the event that the mountain in question had to be at least a few thousand feet high, and that the relative speed and change in direction would likely have caused a tremendous (if not fatal) G-force to anyone inhabiting the sphere. If this was a secret air force UNmanned project, why would this test flight have been done in full view of the city between us?