Winter Solstice冬至
25° Ssouth of east · 東偏南 25°
The farthest south the Sun ever rises. It lingers here for days, then turns back north.
一年中日出最偏南的時候。它在這裡停留好幾天，然後掉頭往北。
Astronomy · Lesson 16 · 天文教育 第16課
Why Does the Sun Rise in a Different Place Every Day?太陽為什麼每天從不同的地方升起？
The Sun rises due east only around the equinoxes. Stand in Changhua and watch the sunrise point slide along the horizon for a whole year, then step inside a 4,000-year-old sunrise calendar at Taosi.
太陽只有在春分、秋分前後才從正東升起。站在彰化，看一整年的日出點沿著地平線滑動；再走進陶寺四千多年前的日出日曆。
Big idea · 一句話看懂
Because Earth's axis is tilted, the Sun's daily path shifts north and south during the year, so the place where it rises slides along the horizon: about 26 degrees north of east in June and 25 degrees south of east in December in Changhua. Ancient people used this swing as a calendar.
因為地軸傾斜，太陽每天走的路一年之中南北移動，它升起的地方就沿著地平線來回滑動：在彰化，六月從東偏北約 26° 升起，十二月從東偏南約 25° 升起。古人就拿這個擺盪當日曆。
3D Model · 3D 模型
Watch the Sunrise Point Swing 看日出點來回擺盪
You are standing in Changhua at sunrise, facing east. Press Play: each second is 12 days, and every sunrise leaves a colored dot on the horizon. Watch the Sun slide north to the summer solstice post, stop, and turn back. The thin arcs are the Sun's paths across the sky. Switch to Sky dome to see why the sunrise point moves, then choose Taosi to stand inside a 4,000-year-old sunrise calendar.
你站在彰化，面向東方看日出。按「播放」：一秒是 12 天，每一次日出都在地平線上留下一個彩色的點。看太陽往北滑到夏至的標竿、停下來、再折返。細細的弧線是太陽在天上走的路。切換到「天空圓頂」看日出點為什麼會移動，再選「陶寺」，走進四千多年前的日出日曆。
Drag to look around · 拖曳轉動視角
This 3D model needs WebGL, which this browser does not support. The sunrise chart and today's sunrise still work.
這個瀏覽器不支援 WebGL，無法顯示 3D 模型；一年的日出方位圖與今天的日出一樣能用。
- Colored dots: where the Sun rose on each day of this year so far (orange in summer, blue in winter)
彩色點：今年到這一天為止，每天太陽升起的地方（夏天橘、冬天藍） - Posts: the summer solstice (north), equinox (due east), and winter solstice (south) sunrise points
標竿：夏至（北）、春秋分（正東）、冬至（南）的日出點 - Arcs: the Sun's path across the sky on the solstices, the equinoxes, and the chosen day (gold)
弧線：冬夏至、春秋分與選定這一天（金色）太陽在天上走的路 - Sunrise times and directions are real for each place and day; the Sun is drawn three times its true size, and the Taosi pillars are a simplified reconstruction
日出時刻與方位是各地、各天的真實數據；太陽畫成真實大小的 3 倍，陶寺的柱子是簡化的重建
In the Face east view, the screen shows about 85 degrees of horizon from side to side, so both turning points fit at once, even at Taosi. The horizon is treated as flat, like the sea; real hills make the Sun appear a few minutes later and a little farther south. Sunrise is when the top of the Sun touches the horizon, the same rule the Central Weather Administration uses.
「面向東方」的畫面左右約 85 度，兩個轉折點可以同時看到，陶寺也一樣。地平線當成像海面一樣平；真實的山會讓太陽晚幾分鐘、稍微偏南才露臉。日出的定義是太陽上緣碰到地平線，和中央氣象署相同。
Sun position: J. Meeus, Astronomical Algorithms, chapter 25; checked day by day against the Central Weather Administration's sunrise and sunset tables (Open Government Data License, version 1.0). Henge dates calibrated with the CWA's 2026 henge forecast for Taipei. Taosi pillars: simplified from published descriptions of the Taosi observatory (13 pillars, 12 gaps), not a survey. The scenery is drawn.
太陽位置：Meeus《天文演算法》第 25 章，並逐日對照中央氣象署〈日出日沒時刻〉開放資料（政府資料開放授權條款第 1 版）。懸日日期以氣象署 2026 年台北懸日預報校準。陶寺的柱子依陶寺觀象台已發表的描述簡化（13 根柱、12 道縫），不是實測。景物是繪製的。
Reading · 英文閱讀
16
Unit 16: Why Does the Sun Rise in a Different Place Every Day?
Where does the Sun rise? Most people say "in the east," and that is almost right. But if you watch the sunrise from the same window every week and compare it with a landmark, such as a tall building or a mountain, you will notice something surprising. The Sun comes up in a slightly different direction each day. In summer it rises north of east, and in winter it rises south of east.
太陽從哪裡升起？大多數人會說「東方」，這幾乎是對的。但如果你每個星期都從同一扇窗戶看日出，拿一個地標（像是一棟高樓或一座山）來比對，你會發現一件令人驚訝的事：太陽每天升起的方向都稍微不一樣。夏天它從東偏北升起，冬天從東偏南升起。
In Changhua, the sunrise point swings to about 26 degrees north of east in June and about 25 degrees south of east in December. That is more than 50 degrees along the horizon, the width of five fists held at arm's length. The Sun rises due east only around the spring and fall equinoxes, in March and September. The sunset point swings the same way in the west.
在彰化，日出點六月擺到東偏北約 26°，十二月擺到東偏南約 25°，沿著地平線總共超過 50°，差不多是手臂伸直時五個拳頭的寬度。太陽只有在三月和九月的春分、秋分前後，才從正東升起。西邊的日落點也照同樣的方式擺動。
Why does this happen? Earth's axis is tilted by about 23.5 degrees. As Earth travels around the Sun, the Sun's daily path across our sky shifts north for half the year and south for the other half. Each day the Sun follows a circle across the sky, and the place where that circle meets the horizon is where the Sun rises. When the whole circle moves north, the sunrise point moves north too.
為什麼會這樣？地軸傾斜了大約 23.5°。地球繞著太陽走，太陽每天在我們天空中走的路，半年往北移、另外半年往南移。太陽每天沿著天上的一個圓走，這個圓和地平線相交的地方，就是太陽升起的地方。整個圓往北移，日出點也跟著往北移。
The sunrise point does not move at the same speed all year. Near the equinoxes, it moves almost one Sun-width every day. Near the solstices, it slows down, seems to stand still for several days, and then turns around. The word solstice comes from Latin words meaning "the Sun stands still." The Chinese names, 夏至 and 冬至, mean that summer and winter have reached their limit.
日出點不是一年到頭都用同樣的速度移動。春分、秋分前後，它每天移動將近一個太陽的寬度；接近夏至、冬至時，它慢下來，好幾天看起來幾乎不動，然後掉頭往回走。英文 solstice 來自拉丁文，意思是「太陽停住」；中文的「夏至」「冬至」，意思是夏天、冬天走到了盡頭。
Ancient people noticed this swing and used the horizon as a calendar. At Taosi in Shanxi, China, archaeologists found the remains of an observatory more than 4,000 years old: a half circle of thirteen rammed-earth pillars. Standing at the center, an observer could watch the Sun rise through the gaps between the pillars. On the winter solstice it rose in the second gap, and on the summer solstice in the twelfth. Knowing the date helped people decide when to plant and when to harvest.
古人注意到這個擺盪，就把地平線當成日曆。在中國山西的陶寺，考古學家發現一座四千多年前的觀象台遺跡：十三根夯土柱排成半圓。站在中心，觀測者可以看著太陽從柱子之間的縫隙升起：冬至從第二道縫升起，夏至從第十二道縫升起。知道日期，就能決定什麼時候播種、什麼時候收成。
You can see the swing in a city, too. When a long, straight street points to where the Sun sets, the Sun can hang right at the end of the street between the buildings. In New York this is called Manhattanhenge, and in Taiwan it is called 懸日, the "hanging Sun." Because the sunset point passes each direction twice a year, once going and once coming back, there are two henge seasons. Look below for today's sunrise in Changhua and a finder that tells you when the Sun will line up with a street.
在城市裡也看得到這個擺盪。一條又長又直的街道如果對準太陽落下的方向，太陽就會剛好掛在兩排大樓之間的街道盡頭。在紐約這叫「曼哈頓懸日」，在台灣叫「懸日」。因為日落點一年會經過每個方向兩次（去一次、回來一次），所以一年有兩段懸日季。看看下面：今天彰化的日出，以及一個告訴你太陽哪天會對準一條街的查詢工具。
Read aloud · 課文朗讀
Questions · 閱讀理解
Does the Sun always rise due east? Explain.
No. It rises due east only around the equinoxes in March and September. In summer it rises north of east and in winter south of east; in Changhua the swing is about 26 degrees north and 25 degrees south.
Why does the sunrise point move during the year?
Because Earth's axis is tilted. As Earth goes around the Sun, the Sun's daily path across the sky shifts north and south, so the place where the path meets the horizon moves too.
How did the pillars at Taosi work as a calendar?
An observer stood at the center and watched the Sun rise through the gaps between thirteen pillars. Each gap matched a time of year: the Sun rose in the second gap on the winter solstice and in the twelfth on the summer solstice.
Words & Phrases · 生字及片語
direction(n.)方向Which direction is the train station from here?從這裡往哪個方向是火車站？landmark(n.)地標Taipei 101 is a famous landmark in Taiwan.台北 101 是台灣有名的地標。due(adv.)正（東、西、南、北）Walk due north for ten minutes, and you will see the river.往正北走十分鐘，你就會看到那條河。turn around(phr. v.)掉頭；折返We missed the exit, so we had to turn around.我們錯過了出口，只好掉頭。pillar(n.)柱子The roof of the old temple rests on six stone pillars.老廟的屋頂靠六根石柱撐著。gap(n.)縫隙；空隙The cat squeezed through a gap in the fence.貓從圍籬的縫隙鑽了過去。observatory(n.)天文台；觀象台We looked at Saturn through the big telescope at the observatory.我們在天文台用大望遠鏡看土星。harvest(n.)收成；收割The farmers had a good rice harvest this fall.農夫今年秋天的稻米收成很好。
Quick Check · 小測驗
1. In Changhua, where does the Sun rise in June?
2. When does the Sun rise due east?
3. What makes the sunrise point swing during the year?
4. Near the solstices, the sunrise point...
5. What did the people of Taosi use to follow the sunrise?
Four Sunrise Points · 四個日出點
Where the Sun rises in Changhua 彰化的太陽從哪裡升起
Times are for Changhua in 2026 (Central Weather Administration). The dates of the solstices and equinoxes shift by about a day from year to year. Press See it in 3D to jump the model to that day.
時刻是 2026 年彰化的數據（中央氣象署）。冬夏至、春秋分的日期每年會差一天左右。按「在模型中看」，模型就跳到那一天。
Spring Equinox春分
0°due east · 正東
The Sun rises due east and races north, almost one Sun-width a day.
太陽從正東升起，快速往北移動，每天將近一個太陽寬。
Summer Solstice夏至
26° Nnorth of east · 東偏北 26°
The farthest north the Sun ever rises, and the earliest sunrises of the year.
一年中日出最偏北的時候，也是一年中日出最早的時候。
Fall Equinox秋分
0°due east · 正東
Due east again, now racing south toward winter.
又回到正東，這次快速往南，朝冬天走去。
Today · 今天
Today's Sunrise and Your Street's Henge 今天的日出與你家街道的懸日
When and where the Sun rises and sets in Changhua today, which way the sunrise point is moving, this year's swing, and a henge finder for any street. Everything is calculated in your browser for today's date.
今天彰化幾點、從哪個方向日出日落，日出點正往哪邊移動，今年的擺盪，以及任何一條街的懸日查詢。全部在瀏覽器裡照今天的日期現算。
Calculating… · 計算中…
Around the World · 世界各地
Calendars on the Horizon 地平線上的日曆
Long before printed calendars, people in China, England, and many other places watched where the Sun rose and set to keep track of the year.
早在印刷的日曆出現之前，中國、英國和世界許多地方的人，就靠觀察太陽從哪裡升起、落下來掌握一年的時間。
陶寺 · Taosi
A 4,000-Year-Old Sunrise Calendar四千多年前的日出日曆
In 2003, archaeologists at Taosi in Xiangfen, Shanxi, uncovered a half-circle platform with the bases of thirteen rammed-earth pillars. Seen from a marked spot at the center, the Sun rose over Taer Mountain through the second gap on the winter solstice, the seventh around the equinoxes, and the twelfth on the summer solstice. Many scholars see it as an early root of the twenty-four solar terms. Choose Taosi in the 3D model to try a simplified version.
2003 年，考古學家在山西襄汾陶寺發掘出一座半圓形的夯土台基，上面有十三根夯土柱的基礎。從中心的觀測點看出去，冬至太陽從第二道縫、春秋分前後從第七道縫、夏至從第十二道縫，在東邊的塔兒山上升起。許多學者認為這是二十四節氣的早期源頭。在 3D 模型裡選「陶寺」，可以試試簡化的版本。
尚書 · Book of Documents
Greeting the Rising Sun寅賓出日
乃命羲和，欽若昊天，曆象日月星辰，敬授人時。——《尚書．堯典》"He ordered Xi and He to follow the vast heaven with care, to chart the Sun, the Moon, and the stars, and to give the people the seasons." (Book of Documents)
The same chapter sends an official to the east to "respectfully greet the rising Sun" and to arrange the spring farm work. Some archaeologists think Taosi may have been the capital of the legendary Emperor Yao, but this is still debated.
同一篇還派官員到東方「寅賓出日，平秩東作」：恭敬地迎接日出，安排春天的農事。有些考古學家認為陶寺可能就是傳說中堯的都城，不過這還在爭論中。
巨石陣 · Stonehenge
Stones That Frame the Solstices對準至日的巨石
In England, the great stones of Stonehenge were raised about 4,500 years ago. Its main axis lines up with the sunrise on the summer solstice and the sunset on the winter solstice, and crowds still gather there to watch. Stonehenge is about 51 degrees north, so its sunrise point swings much farther than Changhua's: almost 40 degrees each way.
英國巨石陣的大石頭大約在 4,500 年前立起。它的主軸對準夏至的日出與冬至的日落，到今天仍有大批人去那裡看。巨石陣在北緯約 51°，日出點擺得比彰化寬得多：往南往北各將近 40°。
懸日 · Henge
Manhattanhenge and Taipei's Hanging Sun曼哈頓懸日與台北懸日
The astrophysicist Neil deGrasse Tyson gave Manhattanhenge its name: the days when the setting Sun lines up with New York's street grid. Taiwan's Central Weather Administration now forecasts 懸日 every year. In 2026, the Sun set at the end of Zhongxiao East–West Road in Taipei from April 30 to May 2 and again from August 10 to 12. Use the finder below to try your own street.
天文物理學家泰森替「曼哈頓懸日」取了名字：夕陽剛好對準紐約棋盤式街道的那幾天。台灣的中央氣象署現在每年都發布懸日預報：2026 年，太陽在 4 月 30 日到 5 月 2 日、以及 8 月 10 日到 12 日，落在台北忠孝東西路的盡頭。用下面的查詢工具試試你家的街。
Myth vs. Fact · 常見迷思
Four things people get wrong 四個常見的誤會
✗ Myth · 迷思The Sun always rises exactly in the east.太陽一定從正東方升起。
✓ Fact · 事實Only around the equinoxes. In Changhua, the sunrise point swings from about 26 degrees north of east in June to about 25 degrees south of east in December.只有春分、秋分前後才是。在彰化，日出點從六月的東偏北約 26°，擺到十二月的東偏南約 25°。
✗ Myth · 迷思The sunrise point moves the same amount every day.日出點每天移動的距離都一樣。
✓ Fact · 事實It moves fastest near the equinoxes, almost one Sun-width a day, and nearly stops for several days around the solstices before turning back.春分、秋分前後移得最快，每天將近一個太陽寬；冬至、夏至前後好幾天幾乎不動，然後才往回走。
✗ Myth · 迷思In winter the Sun rises farther south because Earth is farther from the Sun.冬天太陽從比較南邊升起，是因為地球離太陽比較遠。
✓ Fact · 事實Earth is actually closest to the Sun in early January. The swing comes from the tilt of Earth's axis, which shifts the Sun's daily path north and south.其實地球在一月初離太陽最近。擺盪來自地軸傾斜，它讓太陽每天走的路往北、往南移動。
✗ Myth · 迷思A street can have a henge only once a year.一條街一年只會有一次懸日。
✓ Fact · 事實The sunset point passes each direction twice, once going north and once coming back, so a street that lines up with the sunset gets two henge seasons, like Taipei's in May and August.日落點每個方向都會經過兩次（往北一次、回來一次），所以對準夕陽的街一年有兩段懸日季，像台北的五月和八月。
Remember It · 記憶口訣
Read the horizon 一句話讀懂日出點
Summer north, winter south夏北冬南
In Taiwan, the summer Sun rises north of east, and the winter Sun rises south of east.
在台灣，夏天的太陽從東偏北升起，冬天從東偏南升起。
至 means the end of the road「至」就是走到底
At 夏至 and 冬至, the sunrise point reaches its limit and turns around.
夏至、冬至，日出點走到盡頭，掉頭往回走。
Fast at the equinoxes, slow at the solstices分快至慢
Near 春分 and 秋分 it moves about a Sun-width a day; near 夏至 and 冬至 it barely moves.
春分、秋分前後每天移一個太陽寬；夏至、冬至前後幾乎不動。
Due east twice a year一年兩次正東
Only around March 20 and September 23 does the Sun rise due east and set due west.
只有 3 月 20 日、9 月 23 日前後，太陽才正東升、正西落。
Classroom Activity 1 · 課堂活動一
Make a Sunset Calendar 做一個日落日曆
You need · 準備材料
- A window or a safe spot outside that faces west, with buildings or mountains as landmarks一扇朝西的窗戶或戶外安全的地點，看得到大樓或山當地標
- A long sheet of paper for drawing the skyline一張長紙，用來畫天際線
- Colored pens and a calendar彩色筆和一份月曆
Steps · 步驟
- Draw the western skyline you see, with every landmark.畫下你看到的西邊天際線，每個地標都畫上去。
- Once a week at sunset, stand in exactly the same spot and mark where the Sun goes down. Write the date next to the mark.每週一次，在日落時站在完全相同的位置，標出太陽落下的地方，旁邊寫上日期。
- After two months, connect the marks. Which way is the sunset point moving?兩個月後，把標記連起來：日落點正往哪個方向移動？
- Compare with the chart beside the 3D model. Did your marks move the way it predicts?和 3D 模型旁邊的圖比較：你的標記是不是照它預測的方向移動？
Safety tip: never stare at the Sun, even at sunset. Glance to see where it is, then look at the skyline.
安全提示：即使在日落時也不要直視太陽。瞄一眼看它在哪裡，就把目光移回天際線。
Classroom Activity 2 · 課堂活動二
Build a Mini Taosi 做一個迷你陶寺觀象台
You need · 準備材料
- A paper plate and 13 clothespins or folded paper strips一個紙盤和 13 個曬衣夾（或摺好的紙條）
- A flashlight一支手電筒
- This page's 3D model, set to Taosi本頁的 3D 模型，地點選「陶寺」
Steps · 步驟
- Stand the 13 clothespins in a half circle on the east side of the plate, leaving 12 gaps. Mark the center as the observing spot.把 13 個曬衣夾立在紙盤東半邊排成半圓，留下 12 道縫，在中心標出觀測點。
- In the 3D model, choose Taosi and press Winter solstice, Spring equinox, and Summer solstice. Write down which gap the Sun rises in each time.在 3D 模型選「陶寺」，依序按冬至、春分、夏至，記下每次太陽從第幾道縫升起。
- Hold the flashlight low at the edge of the table as the rising Sun. Move it until its light shines through gap 2, then gap 7, then gap 12 onto the center.把手電筒當成剛升起的太陽，低低地拿在桌邊，移動它，讓光依序穿過第 2、第 7、第 12 道縫照到中心。
- Discuss: why would farmers 4,000 years ago want a calendar like this?討論：四千年前的農夫，為什麼需要這樣的日曆？
Teaching tip: the real half circle was about 20 meters across, so each gap was a narrow slit. The narrower the gaps, the more exact the calendar.
教學提示：真正的半圓直徑約 20 公尺，每道縫都很窄；縫越窄，日曆越準。