Question: who discovered the center of the milky way galaxy
[{'answer': 'Walter Baade', 'provenance': [{'wikipedia_id': '373352', 'title': 'Galactic Center', 'start_paragraph_id': 5, 'start_character': 449, 'end_paragraph_id': 5, 'end_character': 461, 'bleu_score': 1.0, 'section': 'Section::::Discovery.\n'}]}, {'provenance': [{'wikipedia_id': '373352', 'title': 'Galactic Center', 'start_paragraph_id': 5, 'start_character': 177, 'end_paragraph_id': 5, 'end_character': 896, 'bleu_score': 0.9364200532619801, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8847715883725461923}, 'section': 'Section::::Discovery.\n'}]}]