Driving west on A7. Sudden appearance of spherical airborne craft moving at extreme speed. Moved from behind car and travelled over mountain in front before sighting lost. No trail behind. I witnessed a meteor sighting this past summer in Granada and this was not the same. It was a greyish/silver craft moving many times faster than a fighter jet or similar. Searching web for other witnesses - not many cars on road but some. Anyone looking out through windscreen would have seen the craft. The passengers in my car were not looking out at the time.