{"knowledge_schema": {"broad_category": "Physics \u2192 Relativity \u2192 Reference Frames", "refinement": "This problem involves understanding the concept of different inertial frames of reference and how to calculate distances and speeds in those frames.", "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 the ejecta travels in the Galaxy's reference frame over a specified time period."}, "summary": "This problem requires applying concepts from physics, specifically the theory of relativity and reference frames. It involves calculating the distance traveled by supernova ejecta in the Galaxy's reference frame, given that the center of the Galaxy is moving towards the ejecta at a speed of 60,000 km/s. By using the time elapsed in the ejecta's frame (50 seconds), we can calculate the distance using the formula: distance = speed \u00d7 time. The goal is to find the correct distance from the provided options."}