X MM-Newton orbits the Earth in wide arcs which take it a third of the way to the Moon every 48 hours, before it returns to hurtle past our planet at 7000km altitude, travelling at 24,120km/h. Its wide orbit takes it beyond the radiation belts surrounding the Earth, so the 170 wafer-thin cylindrical mirrors of its three X-ray telescopes can enjoy uninterrupted views of celestial objects.
It’s been up there since 1999, launched by the European Space Agency with NASA collaboration, and is far beyond its original proposed mission of examining black holes and early stars. For the last decade it has been aimed at a neutron star in the Scorpius constellation, its mission being to estimate the star’s size and weight.
The results were not what astronomer Victor Doroshenko and colleagues from the University of Tübingen in Germany expected. All
