You can't really make a planet blow up. You can hovewer right-click it and select "explode" in the "object name" menu (As Dan already suggested you for the gamma ray burst). It will make your planet explode in many fragments. The speed in the panel is the one the fragments will escape with (if it is too slow they will collide back) and the number is the number of fragments generated after the "explosion".
Topic: question: how you can blow up planets (Read 5073 times)
