为什么国际上决定未来取消闰秒？
Why did the world decide to eventually drop leap seconds?
闰秒会让金融、通信、导航系统每次都要特殊应对，易出故障；2022年国际计量大会决定最晚2035年起不再插入闰秒，改用更平滑的协调方式。
Leap seconds force finance, communications and navigation systems to make special adjustments and risk glitches; in 2022 the metrology assembly decided to stop inserting them by 2035, using smoother coordination.
难度 专业 · 适合 大众
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：本题原挂出处与答案内容不符，已撤回；具体书目待补，暂不展示来源。
本题原挂出处与答案内容不符，已撤回；具体书目待补。
Previous citation withdrawn as unsupported for this answer; a specific source is pending.
#闰秒 #时间标准
为什么地球自转在变慢，一天真的在变长吗？
Why is Earth's rotation slowing—is a day really getting longer?
月球引起的潮汐摩擦把地球自转的角动量转移给月球轨道，使日长每世纪增加约1.7毫秒；远古一年有400多天，就是证据。
Tidal friction from the Moon transfers Earth's spin angular momentum to the lunar orbit, lengthening the day by ~1.7 ms per century; ancient years had over 400 days—proof.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Zeilik,《Astronomy: The Evolving Universe》第9版,Cambridge University Press,2002
M. Zeilik, Astronomy: The Evolving Universe, 9th ed., Cambridge University Press, 2002
#日长 #潮汐摩擦
卫星导航为什么必须考虑相对论？
Why must satellite navigation account for relativity?
卫星高速运动使钟因狭义相对论变慢，又因离地心远、引力弱使钟因广义相对论变快，二者叠加每天差约38微秒，不修正定位会每天漂移约10公里。
A satellite's speed slows its clock (special relativity) while weaker gravity speeds it (general relativity); the net ~38 microseconds/day must be corrected or positioning drifts ~10 km daily.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Zeilik,《Astronomy: The Evolving Universe》第9版,Cambridge University Press,2002
M. Zeilik, Astronomy: The Evolving Universe, 9th ed., Cambridge University Press, 2002
#相对论 #GPS
古代没有原子钟，人们靠什么来确定'标准时间'？
Without atomic clocks, how did ancients set 'standard time'?
他们靠日晷看日影定当地真太阳时，城市间用统一'标准钟'或天文台授时；中国历代设司天监、钦天监专门测时颁历。
They used sundials for local solar time and a unified civic clock or observatory for standards; China's astronomical bureaus measured and issued time and calendars.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Zeilik,《Astronomy: The Evolving Universe》第9版,Cambridge University Press,2002
M. Zeilik, Astronomy: The Evolving Universe, 9th ed., Cambridge University Press, 2002
#授时 #日晷
为什么'经度'能靠观测星星和携带精确时钟算出来？
Why can longitude be found from the stars plus an accurate clock?
同一时刻不同经度的地方时不同；带着已知标准时的钟出海，比对当地正午（或恒星位置）与钟面时间差，就能算出所在经度，这正是航海钟的用处。
At one instant, local time differs by longitude; carrying a clock set to standard time, you compare local noon (or star positions) with the clock to compute longitude—the purpose of the marine chronometer.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Zeilik,《Astronomy: The Evolving Universe》第9版,Cambridge University Press,2002
M. Zeilik, Astronomy: The Evolving Universe, 9th ed., Cambridge University Press, 2002
#经度 #航海钟
我们日常用的'时间'到底由什么定义？
What actually defines the time we use every day?
现代秒长由铯-133 原子基态两个超精细能级之间跃迁所对应的辐射 9,192,631,500 个周期定义，全世界通过原子钟联网保持协调世界时(UTC)，再按经度划分时区得到本地时间。
The modern second is defined by 9,192,631,500 cycles of the radiation corresponding to the hyperfine transition of the cesium-133 ground state; atomic clocks worldwide keep UTC, and time zones offset it by longitude.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Zeilik,《Astronomy: The Evolving Universe》第9版,Cambridge University Press,2002
M. Zeilik, Astronomy: The Evolving Universe, 9th ed., Cambridge University Press, 2002
#原子钟 #UTC
为什么国际日期变更线不在本初子午线上？
Why isn't the International Date Line at the prime meridian?
本初子午线（0°经线）定的是时刻起点，而日期变更线为避免把同一个国家分到两天、绕开陆地，特意在180°附近弯折，主要关乎'哪天'而非'几点'。
The prime meridian sets the time origin, but the date line bends near 180° to avoid splitting countries and crossing land—it's about 'which day,' not 'what hour.'
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Zeilik,《Astronomy: The Evolving Universe》第9版,Cambridge University Press,2002
M. Zeilik, Astronomy: The Evolving Universe, 9th ed., Cambridge University Press, 2002
#日期变更线 #时区
为什么不同地区的时间不一样？
Why do different regions have different times?
地球自转让太阳依次照亮各地，为免都用同一时刻造成混乱，人们按经度把地球分成24个时区，每差15度大致差1小时。
Earth's rotation brings sunlight to places in turn; to avoid confusion, the world is split into 24 time zones roughly 15° apart, each about one hour different.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Zeilik,《Astronomy: The Evolving Universe》第9版,Cambridge University Press,2002
M. Zeilik, Astronomy: The Evolving Universe, 9th ed., Cambridge University Press, 2002
#时区 #地球自转
什么是'闰秒'，为什么要有它？
What is a 'leap second,' and why do we need it?
地球自转略不规律且长期变慢，原子钟定义的一天比地球自转快一点点，所以偶尔在6月或12月末加（或减）一秒，让协调世界时(UTC)跟上地球。
Earth's rotation is irregular and slowing, so atomic-clock days run slightly ahead; occasionally a second is added (or removed) at the end of June or December to keep UTC in step with Earth.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Zeilik,《Astronomy: The Evolving Universe》第9版,Cambridge University Press,2002
M. Zeilik, Astronomy: The Evolving Universe, 9th ed., Cambridge University Press, 2002
#闰秒 #原子钟
为什么有时候白天也能看到月亮？
Why can we sometimes see the Moon during the day?
月亮本身反射太阳光，只要它和太阳不在完全相反的方向、且天空不太亮，肉眼就能在白天找到它，尤其上弦前后在下午常见。
The Moon just reflects sunlight; when it's not opposite the Sun and the sky isn't too bright, you can spot it by day—common in the afternoon around first quarter.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Zeilik,《Astronomy: The Evolving Universe》第9版,Cambridge University Press,2002
M. Zeilik, Astronomy: The Evolving Universe, 9th ed., Cambridge University Press, 2002
#白天月亮 #月相