The corkscrew shape visible here is created by a phenomenon known as precession; as they move outwards through space, these two jets are slowly tumbling around an axis in a similar way to the motion of a gyroscope or a spinning top slowing down, the orientation of their rotational axes changing as they do so. The scale of this corkscrew is enormous, at 5000 times the size of the Solar System. One remarkable aspect of this observation is that its detailed shape was entirely predicted from spectroscopic measurements by the Global Jet Watch telescopes in the preceding year before the ALMA observations were made. The sequence of these observations allowed researchers to make and test predictions about the paths the jets would take, representing a new milestone in the study of microquasars. The observations have also resolved the question of why the jets are still hot at such great distances from their origin — ALMA’s sensitivity enabled researchers to identify that reheating of the plasma occurs when successive jet surges expand and collide with one another.
