UPSC Prelims 2025 Q77: Geography – Astronomy & Earth - Sun System
Consider the following statements:
I. Anadyr in Siberia and Nome in Alaska are a few kilometres from each other, but when people
are waking up and getting set for breakfast in these cities, it would be different days.
II. When it is Monday in Anadyr, it is Tuesday in Nome.
Which of the statements given above is/are correct?
- (a) I only
- (b) II only
- (c) Both I and II
- (d) Neither I nor II
Answer: (a) I only
Explanation
Anadyr (Russia) and Nome (Alaska, USA) — either side of the International Date Line
| Detail | Anadyr | Nome |
|---|---|---|
| Location | Chukotka, Russia (Asia) | Alaska, USA (North America) |
| Time zone | UTC+12 | UTC−9 (Alaska time) |
| Side of the Date Line | West — calendar day is ahead | East — calendar day is behind |
The two places are close on the map, but the International Date Line (about 180°) runs between them through the Bering Strait.
Statement I — correct. When people wake up in both towns, they are on different calendar days.
Statement II — not correct. Anadyr, west of the Date Line, is ahead. So when it is Monday in Anadyr, it is Sunday in Nome, not Tuesday.
| Crossing the Date Line | Change |
|---|---|
| Going west (America → Asia) | Add a day |
| Going east (Asia → America) | Subtract a day |
Answer: (a) I only.
Why each option is right or wrong
- (a) CORRECT. They are on different days, but Anadyr is ahead: Monday in Anadyr is Sunday in Nome.
- (b) Incorrect. Statement II reverses the direction; Nome is behind Anadyr, not ahead.
- (c) Incorrect. Only Statement I is true; Statement II gets the direction of the day change wrong.
- (d) Incorrect. Statement I is true, because the Date Line passes between the two towns.
Key point
West of the Date Line (Asia) is one day ahead of east of it (America): Monday in Anadyr = Sunday in Nome.
Remember
When it is Monday in Anadyr, it is still Sunday in Nome.
Common mistakes
- Assuming the place farther east is always ahead in time; across the Date Line the rule flips.
- Forgetting the Date Line is the 180° meridian with zigzags around land, passing through the Bering Strait.
- Thinking close places must share a calendar day; Anadyr and Nome are hours apart in clock time but on different days.
Exam tip
Asia side = tomorrow, America side = yesterday. The sun's new day starts just west of the Date Line.
Sources
- NCERT Class VI — The Earth: Our Habitat, Ch 2 (Globe: Latitudes and Longitudes)
- NCERT Class XI — Fundamentals of Physical Geography (Time zones)