Lost at Sea: The Search for Longitude
You're invited on a transatlantic cruise aboard an oceangoing yacht, the Miss Adventure,
leaving from England. Soon after setting sail, you encounter storms that
last for weeks. Then a devilishly thick fog envelops the ship for several
days. When the fog finally lifts, the sun is at its apex, and a speck of
land is faintly visible on the horizon. "Land ho!" calls the lookout.
The captain determines quickly with his sextant that the ship is at latitude
42 degrees north, but then discovers to his horror that his chronometer
has stopped. "Oh no!" he shouts, "Where are we?" Thinking
fast, you glance at your super-accurate watch, which is set to Greenwich
time. It reads 4:40 p.m. Knowing that Greenwich time is the time at the
prime meridian of the world, which is 0 degrees longitude, you perform a
quick mental calculation and check the map. "No problem, Cap'n,"
you call out confidently. "That land is...
(HINT: The Earth rotates in an easterly direction at a rate of about 15
degrees per hour, or 5 degrees every 20 minutes.)
(ANOTHER HINT: When the sun is at its apex, it's as high in the sky as it's going
to be that day. That means it's noon.)
A.) Havana!" (longitude: about 82 degrees west of Greenwich)
B.) Chicago!" (longitude: about 88 degrees west)
C.) Tashkent, Uzebekistan!" (longitude: about 70 degrees east)
D.) Cape Cod!" (longitude: about 70 degrees west)