Question: what is it called when day and night are equal length
[{'answer': 'equinox', 'provenance': [{'wikipedia_id': '10100', 'title': 'Equinox', 'start_paragraph_id': 1, 'start_character': 3, 'end_paragraph_id': 1, 'end_character': 10, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '10100', 'title': 'Equinox', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 286, 'bleu_score': 0.74085166947386, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17084054773090674954}, 'section': 'Section::::Abstract.'}]}]