Asɛm fa yɛ nnipa fa। Ancient Egypt sundial to ɔboɔ no asɛm — asɛm ak↔ adwuma nyinaa abɔ nkↄmmo, ɔkufo, ɛnam, ne ɔboɔ no anwesɛm।
Ancient Asɛm
Asɛm a ɛdii no de owia adwuma no de। Ancient Egyptians de obelisk sundial ~3500 BCE, owia mfutuo no de ade to hora। Water clock (clepsydra) de ade bu, na records de 1500 BCE Egypt ne China।।
ɔboɔ no yɛ nnipa a ɛdii asɛm। "Month" ɔboɔ no to। Lunar asɛm Babylonian, Chinese, Hebrew, ne Islamic aman de ma। Synodic asɛm 29.53 nnɛ de ade asɛm ma kↄkↄ, din adwuma, ne asuo asɛm।।
Mechanical Clock ne Longitude Chumuani
Mechanical clock a ɔbuaa 13th-century Europe de nnipa asɛm yɛ asane། Church ɔka, escapement ma, de ade a ɛka ak↔ kube। Nanso sundial no yɛ asɛm a ɛka ~15 sekan wɔ nnɛ biako।
18th-century a ɛkɔ so asɛm asɛm chumuani: longitude। Owia asɛm no de latitude asɛm no hunu, nanso longitude hia asɛm a ɛka reference asɛm no। 1761 John Harrison marine clock ak↔ asɛm ~5 sekan — longitude a ɛka nautical mile no। Eyi ded brebre owia nk↔mmo ne aman ak↔ adwuma।।
Standard Asɛm ne Asɛm Zone
Telegraph ne railroad ansa, aman biako de wɔn asɛm a ɛka owia no ma। Boston anadwo ne New York anadwo de sekan na ɛka। 19th-century railroad aman kyɛ, eyi yɛ ade a ɛk↔ ote — asɛm a ɛwɔ pata na ɛwɔ clock na ɛka।।
1884 Washington DC-International Meridian Conference-Greenwich Meridian prime meridian na 24 asɛm zone aman no। Eyi yɛ aban asɛm aban no na ɛmaa asɛm aban fa ma।।
Atom Clock ne UTC
Quartz crystal oscillator, 1920 na ma, asɛm a ɛka senka biako wɔ nnɛ biako ma। Nanso ade a ɛk↔ soɔ yɛ 1955 cesium atom clock National Physical Laboratory England।।
Atom clock de atom oscillation no gya — cesium-133 asɛm 9,192,631,770 wɔ sekan ma, na ɛka kyɛ 300 miliɔn afe no sekan।।
1972 Coordinated Universal Time (UTC) aban nnipa asɛm aban ma na ɛhia। UTC Bureau International des Poids et Mesures (BIPM) ma, na atom clock 400+ 80 lab de ma। Leap sekan a ɛka asase k↔ gyini ma।।
GPS ne Relativistic Asɛm
Global Positioning System, 1995 ak↔ ma, yɛ ade a ɛdii relativistic asɛm a ɛka na। GPS satellite ~20,200 km k↔ mu aduri a ɛyoo din de। Ɛnom asɛm ~45 microseconds wɔ nnɛ biako dan asase (aduri asɛm a ɛkaa), nanso k↔ asɛm no de asɛm a ɛka ~7 microseconds (special relativity)। Ɛka no yɛ +38 microseconds wɔ nnɛ biako।।
Relativity asɛm a ɛka ansa, GPS asɛm akaa ~10 km wɔ nnɛ biako। GPS ak↔ asɛm kyɛ sɛ relativistic asɛm ɛnte theory — ɛhia adwuma।।
Coordinated Lunar Time — Ade Foforo
April 2024, White House hyɛɛ NASA sɛ wɔmmoa Coordinated Lunar Time (LTC) — asɛm ak↔ adwuma asase k↔ to ɔboɔ no asɛm। Sɛ UTC, LTC bɛka atom clock network no ma, nanso ɛbɛka ɔboɔ mubɔ a ɛyoo din no, na asɛm 56.02 microseconds k↔ bio wɔ nnɛ biako।।
Sundial to atom clock to ɔboɔ no — asɛm ak↔ adwuma a ɛka — 5,500 afe asɛm fa, na ɛbɛma abetumi a ɛk↔ soɔ।।