Question

If a star crosses the meridian as seen from Greenwich, England, at midnight, when does it cross the meridian for someone at a longitude of 90° West?

A. 9 PM
B. 9 AM
C. 6 AM
D. midnight

Answer 1

If a star crosses the meridian as seen from Greenwich, England at midnight, it will cross the meridian for someone at a longitude of 90° West at 9 PM.

Step-by-step explanation:

The Earth rotates 360 degrees in 24 hours, so each hour it rotates 360/24 = 15 degrees. Therefore, if a star crosses the meridian as seen from Greenwich, England at midnight, it will cross the meridian for someone at a longitude of 90° West at 9 PM. This is because 90° West is 6 hours behind Greenwich time, and 6 hours before midnight is 6 PM.