Los Angeles CA (SPX) Sep 01, 2025 New results from NASA's Chandra X-ray Observatory reveal that Cassiopeia A's progenitor star violently reshaped its interior just hours before it exploded. This previously hidden stellar upheaval helps explain the asymmetry of the remnant and may even have triggered the supernova itself. Cassiopeia A, one of the most studied remnants in the night sky, began as a massive star that lived for
