USAAAO 2026, I кръг — Задача 5
USAAAO 2026 - First Round · 9 февруари 2026 г.
Problem writers
Problem writers: Srihari (Hari) Balaji, Vincent Bian, Ferdinand, Hagan Hensley, Elizabeth Lee, Joe McCarty, Lucas Pinheiro, Feodor Yevtushenko
Условие
The following figure is used for questions 4, 5, and 6.
You are stranded on a remote island somewhere on Earth, at an unknown date and time (in the century). You look up and see the night sky.
(For avoidance of doubt, the illuminated side of the Moon is on the left.)
Which of the following is the best estimate of the month of the year?
(a) January
(b) April
(c) July
(d) September
(e) November
Отговори
- E
Решение
Solution: The moon is roughly illuminated with the illuminated side facing east (waning), which means that the Sun is about east along the ecliptic from the moon.
Since the moon is in Leo - where the Sun would be in September - this suggests the Sun is , or two months, east of this point. So the current month is November.
Answer: E
Оригинал в Архива: usaaao_first_exam_2026.pdf · официални решения: usaaao_first_exam_solutions_2026.pdf