A telescope array still in early construction was pointed at the Helix Nebula and came back with 22 arcs of shocked gas in the faint outskirts — each one carved by an invisible clump of a dead star’s ejecta that interstellar space is pulling apart

Five of MOTHRA's eventual 30 mounts were working when the array was aimed at the Helix as a commissioning target. Almost nothing is visible at the centre of any of the 22 bow shocks it found, and the way their size collapses with distance puts a rough number on how long a fragment of a dead star lasts once the interstellar medium gets hold of it. The post A telescope array still in early…