Astro Watch : Radio astronomers have used a radio telescope network the size of the Earth to zoom in on a unique phenomenon in a distant galaxy: a jet activated by a star being consumed by a supermassive black hole. The record-sharp observations reveal a compact and surprisingly slowly-moving source of radio waves.An international team of radio astronomers led by Jun Yang (Onsala Space Observatory, Chalmers University of Technology, Sweden) studied the new-born jet in a source known as Swift J1644+57 with the European VLBI Network (EVN), an Earth-size radio telescope array. The results, published in a paper in the journal Monthly Notices of the Royal Astronomical Society, will also be presented at the European Week of Astronomy and Space Science in Athens, Greece, on Friday 8 July 2016.When a star moves close to a supermassive black hole it can be disrupted violently. About half of the gas in the star is drawn towards the black hole and forms a disc around it. During this process, large amounts of gravitational energy are converted into electromagnetic radiation, creating a bright source which is visible at many different wavelengths. One dramatic consequence is that some of the star’s material, stripped from the star and collected ...