I was going to my car which was parked in my driveway to grab some items out of it, and when I opened the door I could instantly smell something which I could only relate to the smell of sulphur outside, and while making my way to my vehicle I noticed a object hovering under the clouds about half a mile away, as I noticed something shining in the corner of my eye which was odd as it was cloudy outside. This object was grey but very bright to the point where it appeared to be reflective. There was a faint yellow glow around the perimeter of the object. As far as I could tell I'd have to say it was between 35 and 55 feet in diameter. I could not tell how thick it was as I could not see the top of the object as it was in the clouds, but the part of the object that was visible appeared to be around 7 or 8 feet thick. I wasn't sure what to make of the object as I had never seen anything like that in my life, and I felt that I was indeed seeing something that could have very easily been from another world, but as I was unable to make out exactly how thick/tall this object was there was no way of knowing for sure. After standing outside and observing it for just over a minute and a half I went inside to grab my digital camera and when I went back outside the object had vanished much to my disappointment. I did not in any way feel scared or threatened by this object and I only wish it would have been a clear day so I would have had a better overall look of this object. This was my first UFO sighting.