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Sunrise on the Equinox
The Earth turns to the east as it rotates. It spins 1 degree longitude every 4 minutes. On the equinox, locations at the same longitude experience sunrise at the same time.

Animation: Sunrise on the Equinox



Seasons Comparison

Time and Longitude
Locate the Prime Meridian and Greenwich, England on the map.

  • Longitude: How far east or west of the Prime Meridian do you live (in degrees)?
  • Time: What is the time difference between Greenwich, England and your home town (in hours and minutes)?

Time Clues on March 9
These facts will help you use the time clues to estimate the longitude of the Mystery sites:

  • The Prime Meridian is the reference line you will use for measuring longitude.
  • Greenwich, England is the reference point you will use for measuring time.