Question: how long does it take for the milky way to rotate
[{'answer': 'galactic year', 'provenance': [{'wikipedia_id': '5059853', 'title': 'Galactic year', 'start_paragraph_id': 1, 'start_character': 4, 'end_paragraph_id': 1, 'end_character': 17, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'cosmic year', 'provenance': [{'wikipedia_id': '5059853', 'title': 'Galactic year', 'start_paragraph_id': 1, 'start_character': 35, 'end_paragraph_id': 1, 'end_character': 46, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '5059853', 'title': 'Galactic year', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 554, 'bleu_score': 0.946668591300401, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8791131805323228146}, 'section': 'Section::::Abstract.'}]}]