Glossary term: 年
Description: 一年是地球绕太阳一周的时间，但 "绕行一周 "有多种定义。太阳从一年到下一年出现在天空中完全相同位置的时间是一个回归年，也称为太阳年，约为 365.24 天。以遥远的恒星为参照物，地球完成一个轨道所需的时间是一个恒星年。两者之间的差异约为 20 分钟（恒星年稍长），这是由于地球自转轴的偏移造成的，即地球自转轴在空间中非常缓慢地改变其方向。此外还有近点年：在椭圆轨道上，地球与太阳的距离时近时远。近点年是随后两次最接近太阳（"经过近日点"）之间的时间差。对于太阳系内外的其他行星，其 "年 "的定义与这些行星围绕太阳或其他中心恒星的轨道类似。
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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher The translation of this term and its definition is still awaiting approval
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