- Where is the line of sunrise at 0h UT on January 1?
- What is the first place where the Sun rises on January 1, local time?
- What is the first point of land where the Sun rises on January 1, local time?
- What is the first permanently inhabited place where the Sun rises on January 1, local time?
- What about Kiribati?
- How much does refraction affect the time of sunrise?
- What is the first place on each continent where the Sun rises on January 1, local time?
- What is the first place in the United States where the Sun rises on January 1, local time?
- What is the last place the Sun will set on December 31, local time?
When and where does the Sun first rise at the beginning of a year?
The answer depends to some extent on the exact question being asked.
On any January 1, the Sun is continuously above the horizon across most of Antarctica. If the question is really, "Where will the Sun be first seen after the beginning of the year?" the answer is simple: Antarctica.
If you are really interested in the first sunrise, the question becomes more involved.
Questions about the times of sunrise and sunset can usually be answered without reference to a specific year because the Sun's position in the sky on any given date is almost the same from year to year. For places at low to middle latitudes, a sunrise/sunset table computed for one year can be used in any other year. However, at polar latitudes the year to year differences are magnified and, for such places, a sunrise/sunset table may differ by several minutes from year to year. Although the basic Earth-Sun geometry on any given date is pretty much the same from year to year, care must be taken when considering arctic or antarctic places.
The fundamental issue in identifying the first sunrise is clarifying when a new day, or a new year, begins. Does it begin at local midnight, in the time zone defined by the local jurisdiction? Or does it begin at midnight on the meridian of Greenwich, England (the zero longitude meridian), that is, 0 hours Greenwich Mean Time? Astronomers refer to the latter instant as 0 hours Universal Time (0h UT) and that is the usage here.
The Washington Prime Meridian Conference of 1884, which established the Greenwich Meridian as the prime meridian, did not settle this matter. The final resolution states:
That the Conference proposes the adoption of a universal day for all purposes for which it may be convenient, and which shall not interfere with the use of local or other standard time where desirable.
Thus, the two conflicting definitions for the beginning of the day are enshrined in international law.
For most locations, local time is defined as the time zone (civil time) established by the local governing authority. For example, in the United States, the Department of Transportation [15 U.S.C. §6(IX)(260-7)] administers local time zones. On the high seas and in Antarctica, however, local time is the time zone defined by the nearest meridian of longitude that is an integer multiple of 15°.
2. Where is the line of sunrise at 0h UT on January 1?
At 0h UT on January 1, the Sun is rising along a line that runs from about 650 km east of Kerguelen Island in the Indian Ocean to about 640 km east of Amsterdam Island, through the Nicobar Islands, up along the Burma-Thailand border, through China, along the China-Outer Mongolia border, along the China-Russia border, through Siberia and out into the Arctic Ocean just north of the Poluostrov peninsula. All places along this line experience sunrise simultaneously at 0h UT on January 1. There is no unique "first sunrise" location.
3. What is the first place where the Sun rises on January 1, local time?
The first place where the Sun rises, local time, is along the International Date Line, all of which is in the Pacific Ocean. Although the International Date Line makes some zigzags to the east, the place on the line where the Sun rises first on January 1 is in the far south, near the Antarctic Circle, where the line is intersected by the terminator (day/night line). Here, the Sun dips just below the horizon and then rises again almost immediately at midnight local time. The longitude is 180° exactly, and we take the local time to be 12 hours ahead of UT. Considering the angular size of the Sun and the effect of mean atmospheric refraction, the southern limit of the terminator on January 1 is approximately at latitude 66° 5' S. Farther south the Sun is continuously above the horizon. However, the actual southern boundary can vary by several arcminutes, depending on the exact place of the Earth in its orbit1 and local weather conditions. This location is in the extreme southern part of the Pacific Ocean with no land nearby.
4. What is the first point of land where the Sun rises on January 1, local time?
The southern limit of the terminator on January 1 is in the Pacific Ocean far from the sight of land. The first place in Antarctica west of the International Date Line where the Sun could rise that day is at the headland between the Dibble Glacier (134° 37' E) and Victor Bay. At 135° 53' E, the Sun rises at about 12:05 AM on January 1, local time, which is 15:05 on December 31, UT. However, a sunrise is possible about 12:23 AM on January 1, local time, (13:23 on December 31, UT) on the northern tip of Young Island (162° 17' E) in the Balleny Islands. Young Island extends to 66° 13' S, so under unusual atmospheric conditions, the Sun may be seen to set there on December 31. The chances of having a sunset at Young Island are about 10-15%.
The sunrise times and places assume normal values of refraction. If you are worried about not seeing the sunrise because of refraction effects, the place to be assured of seeing the sunrise is at the northern tip of the Dibble Glacier (66° 0' ± 1' S, 134° 37' ± 2' E) where the Sun rises at about 12:25 AM on January 1, local time (15:22 on December 31 UT).
5. What is the first permanently inhabited place where the Sun rises on January 1, local time?
The first populated land where the Sun rises on January 1 is Kahuitara Point (44° 16' S 176° 9' W) on Pitt Island in the Chatham Islands, a dependency of New Zealand. The Sun rises there at about 4:50 AM local time, which is 16:05 December 31 UT.
6. How do sunrise times in Kiribati compare with those elsewhere in the world?
In 1995, Kiribati moved the International Date Line so that so that the entire country is on the western side of it. As a result, the line is as far east as 150°, farther east than Honolulu. Because of this eastern bulge in the International Date Line, Kiribati had put forth the claim that Caroline Island (10° 0' S 150° 15' W) would be the first point of land where the Sun would rise. However, the Sun does not rise here until about 5:45 AM January 1, local time (15:45 December 31 UT), about 30 minutes after it rises in the first place in the Antarctic. Although Caroline Island is in tropical seas, it is not more accessible than Antarctica. Caroline Island is actually an atoll of 22 small islets stretched over 11 km protected by a very shallow reef, reachable by only shallow draft boat or seaplane.
Similarly, the Sun rises at South East Point on Christmas Island, the most south-easterly of the inhabited islands in Kiribati, at about 6:30 AM January 1, local time (16:30 December 31 UT). The sunrise at Pitt Island in the Chatham Islands of New Zealand occurs about 25 minutes earlier.
7. How much does refraction affect the time of sunrise?
Aside from the sunrise times determined by HMNAO, most of the sunrise times given elsewhere for these places are later than the times given here, which indicates those determinations of sunrise do not include the effects of refraction. The atmosphere of the Earth bends the light of the Sun, on average, by about 34' at the horizon at sea level, making the Sun appear above the horizon when it is geometrically below the horizon. In January, the angle that the Sun makes with the horizon as it rises and sets becomes shallower as you go farther south, so the effect of refraction on sunrise and sunset times becomes more pronounced. That is, as you go further south, the Sun is skimming along the horizon, just below the geometric terminator, but can be seen above the horizon. At some extreme southern latitudes (near the Antarctic Circle), the Sun stays in the region between the geometric terminator and 34' below the geometric terminator and never appears to set. The amount of refraction is a function of the density of the atmosphere, so the lower temperatures near poles increase the amount of bending of the light by the Earth's atmosphere. Consequently, the Sun does not appear to set 25-30' north (outside) the Antarctic Circle on January 1. However, at the equator, the Sun rises nearly perpendicular to the horizon, so the difference between time the Sun rises and when it is above the geometric terminator is only a few minutes. Once refraction is included, the Sun is seen earlier in the Antarctic and at Pitt Island than it is seen at Caroline Island and Christmas Island, respectively.
The value of 34' for refraction at the horizon is its average value; the actual value can vary depending on the local temperature, atmospheric pressure, and other weather-related variables. For example, someone watching the sunrise where the temperature is 32°F (0°C) will see the Sun approximately 25 seconds earlier than someone watching it where the temperature is 86°F (30°C), but otherwise identical weather conditions. In addition, the amount of refraction is color dependent. Suppose two people are standing side by side watching the sunrise. One person is wearing glasses that only admit blue light while the other is wearing glasses that only admit red light. The person wearing the blue glasses would see the Sun rise a few seconds before the person wearing the red glasses. This difference in refraction with color is also the source of the green flash.
A change in the amount of refraction near the equator will only change the the time of sunrise. There is a 32% chance that the time of sunrise will be off by more than 38 seconds. Consequently, times of sunrise are calculated only to the nearest minute. Near the northern and southern extremes where the Sun is skimming the horizon, a change in refraction can cause the Sun to appear further north or south than expected either delaying an expected sunrise by several minutes or eliminating it because the Sun never set! At the extreme southern limit of the terminator in Antarctica, the January 1 sunrise has a 32% chance of occurring more than 18 km north or south of its predicted position.
8. What is the first place on each continent where the Sun rises on January 1, local time?
|Area||Place of first sunrise||Position||Time|
|Antarctica (2000)2||66° 3' S||135° 53' E||15:08 (12/31)||12:08 AM|
|Antarctica (2001)2||66° 7' S||135° 49' E||15:05 (12/31)||12:05 AM|
|New Zealand||Table Cape||39° 6' S||178° 0'E||16:45 (12/31)||4:45 AM|
|Australia||Cape Pillar, Tasmania||43° 4' S||148° 0' E||18:32 (12/31)||4:32 AM|
|Australian mainland||Cape Howe, New South Wales||37° 30' S||149° 59' E||18:42 (12/31)||4:42 AM|
|Asia||Chaplino, Russian Siberia||64° 25' N||172° 16' W||21:26 (12/31)||10:26 AM|
|Africa||Fort-Dauphin, Madagascar||25° 1' S||47° 0' E||02:05||5:05 AM|
|African mainland||Mocambique, Mozambique||15° 0' S||40° 44' E||02:51||4:51 AM|
|Europe||Ukraine just west of Donetsk, Russia||48° 22' N||40° 2' E||05:11||8:11 AM|
|South America||Cabo San Juan, Argentina||54° 45' S||63° 45' W||07:43||4:43 AM|
|South American mainland||Cabo de Sao Tome, Brazil||21° 54' S||40° 59' W||08:04||5:04 AM|
|South American mainland||Punta de Monsaras, Brazil||19° 32' S||39° 50' W||08:04||5:04 AM|
|North America||Cape Race, Newfoundland||46° 40' N||53° 8' W||11:17||7:47 AM|
|North American mainland||Cape Breton, Nova Scotia||45° 57' N||59° 47' W||11:41||7:41 AM|
All of these calculations are made for sea level and include standard atmospheric refraction. There is a chance that at an elevated location near the described spot, the Sun will rise there first because of its altitude above sea level. If there is a 1000 m high mountain 100 km west from where sunrise occurs at sea level, the peak of the mountain will see the Sun rise at about the same time as at the sea level position. For hills and mountains near the coast, a 30 m (100 ft.) change in altitude will change the time in sunrise by about 1 minute.
9. What is the first place in the United States where the Sun rises on January 1, local time?
If territories are included, the first U.S. sunrise on January 1 is at about 7:25 local time (19:25 December 31 UT) at Peacock Point (19° 16' N 166° 35' E) on Wake Island. However, aside from the occasional government employee or contractor, Wake Island is uninhabited. The first inhabited land in the U.S. where the sunrise will occur is at about 6:45 AM January 1, local time (20:45 December 31 UT) in Guam at Inarajan (13° 17' N 144° 45' E) about 3 minutes after it rises on the peak of Lamlam Mountain, Guam.
Excluding territories, the earliest sunrise in the U.S. is nearly 15.5 hours later at about 7:05 Eastern Standard Time (EST), or 12:05 UT, at the summit of Cadillac Mountain, Maine (44° 21' N 68° 13' W). The earliest sunrise at sea level occurs at about the same time at Lubec, Maine (44° 50' N 67° 0' W) and Siasconset, Massachusetts (41° 15' N 69° 58' W) on Nantucket Island. About a minute later or 7:06 EST (12:06 UT), the Sun rises at the peak of Katahdin Mountain, Maine (45° 54' N 68° 55' W), which is also the time when Miami Beach, Florida (25° 47' N 80° 16' W), the first major metropolitan area, sees the Sun rise.
10. What is the last place where the Sun will set on December 31, local time?
For those who are nostalgic and prefer looking back on past accomplishments rather than forward towards the unknown future, the place to be is Falealupo, Samoa (13° 25' S 172° 45' W) where the Sun does not set until about 7:00 PM December 31, local time (06:00 January 1 UT).
1 The length of the calendar year is not an exact match to the length of the tropical year (the time between one spring equinox and the next). Nor are either the calendar year or the tropical year an exact number of days. As a result, the Sun's latitude varies by a few arc minutes from year to year. For example the Sun's declination at 0 hr UT on Jan. 1 between 1949 and 2008 varied from –23° 0' 43."5 and –23° 6' 22."4
2 The year to year change in the declination of the Sun at 0 hr on January 1 and the general east-west direction of the Antarctic coastline can cause fairly large changes in the place and time of sunrise. The positions for 2000 and 2001 are given as examples. Even larger changes may occur when non-standard refraction effects such as the Novaya Zemlya effect are included.