{"knowledge_schema": {"broad_category": "Physics \u2192 Relativity \u2192 Reference Frames", "refinement": "This problem involves understanding the relationship between different inertial frames of reference and how time dilation affects measurements of distance and speed.", "specific_scope": "The focus is on calculating the distance traveled by supernova ejecta in the reference frame of the Galaxy, given the speed of the Galaxy's center relative to the ejecta and the time elapsed in the ejecta's frame.", "goal": "Determine the distance traveled by the ejecta in the Galaxy's reference frame over a specified time period."}, "summary": "This problem requires applying concepts from physics, specifically the relationship between different inertial frames of reference. The ejecta from a supernova is moving towards the center of the Galaxy, which is perceived to be moving at 60,000 km/s from the ejecta's frame. To find the distance traveled in the Galaxy's reference frame over 50 seconds, we need to calculate the distance using the speed of the Galaxy's center and the time elapsed in the ejecta's frame. The goal is to determine the correct distance from the provided options."}