🪐 天文单位（AU）换算Astronomical Unit Converter
天文单位 AU 与千米、英里、光秒、光分、光年、秒差距之间互相换算，1 AU = 149,597,870,700 米（IAU 2012 定义）。Convert astronomical units to kilometres, miles, light-seconds, light-minutes, light-years and parsecs, using the exact IAU 2012 definition 1 AU = 149,597,870,700 m.
点击任意一行可复制该结果；小于 0.0001 或不小于 10¹⁵ 的数值用 × 10ⁿ 科学计数法显示Click any row to copy that result. Values below 0.0001 or at least 10¹⁵ are shown in × 10ⁿ notation
使用说明与常见问题How-to & FAQ
「天文单位（AU）换算」是什么？What is the Astronomical Unit Converter tool?
天文单位 AU 与千米、英里、光秒、光分、光年、秒差距之间互相换算，1 AU = 149,597,870,700 米（IAU 2012 定义）。Convert astronomical units to kilometres, miles, light-seconds, light-minutes, light-years and parsecs, using the exact IAU 2012 definition 1 AU = 149,597,870,700 m.
如何使用「天文单位（AU）换算」？How do I use the Astronomical Unit Converter tool?
在「天文单位（AU）换算」中输入数值并选择原单位，表格会同时列出换算到所有其他单位的结果，可一键复制。Enter a value in the Astronomical Unit Converter and choose the source unit; the table shows the value in every other unit at once, ready to copy.
1 天文单位是多少？How long is one AU?
国际天文学联合会 2012 年把 1 AU 定义为恰好 149,597,870,700 米，约等于地球到太阳的平均距离，光走完约需 8 分 19 秒。The IAU fixed 1 AU in 2012 at exactly 149,597,870,700 m — roughly the mean Earth–Sun distance, which light covers in about 8 min 19 s.
光年和秒差距怎么定义？How are the light-year and parsec defined?
光年 = 光在一儒略年（365.25 天）走过的距离 = 9,460,730,472,580,800 米；秒差距 = 648000/π AU ≈ 3.2616 光年（IAU 2015 B2 决议）。A light-year is the distance light travels in a Julian year (365.25 days), 9,460,730,472,580,800 m; a parsec is 648000/π AU ≈ 3.2616 light-years (IAU 2015 Resolution B2).
地月距离用的是什么值？Which Earth–Moon distance is used?
使用月球轨道半长轴 384,399 km 作为地月平均距离，这是天文常用值；NASA 月球事实表把它四舍五入为 384,400 km。实际地月距离在约 356,000–407,000 km 之间变化。The Moon's orbital semi-major axis, 384,399 km, the value usually quoted as the mean Earth–Moon distance; NASA's Moon fact sheet rounds it to 384,400 km. The actual distance varies between about 356,000 and 407,000 km.
换算系数准确吗？Are the conversion factors exact?
「天文单位（AU）换算」采用国际单位制（SI）或公认标准中的定义值作为换算系数，结果保留约 10 位有效数字。The Astronomical Unit Converter uses factors defined by the SI or other recognised standards and shows about 10 significant digits.
「天文单位（AU）换算」免费吗？需要注册吗？Is the Astronomical Unit Converter free? Do I need an account?
「天文单位（AU）换算」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Astronomical Unit Converter is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.