“It was discovered by Natasha Hurley-Walker and an honours student, Tyrone O’Doherty. A bright source apparent in some images of radio waves, but not others. Pulsing, with a frequency of 18 minutes. What could it be? A white dwarf? A neutron star? It had been missed in over 30 years of images. Natasha Hurley-Walker describes some of the possibilities…”