The fruit is around 3in in diameter. Zone 7, private yard.
Pomegranate. Commonly cultivated in the Mediterranean. Should grow quite a bit more than the 3 inches diameter you are observing, and become a bit redder when ripe... although I guess depends on the variety.
Rather than a spaceship looks more like royalty if you turn it with the crown facing upwards :).
Looks like pomegranate, or Punica granatum. Pretty common fruit, you can even find it in the supermarket.