Why would it be so catastrophic for Amelia Earhart to not know latitude or longitude?

Answer 1

This all has to do with navigation. In order to go from point A to point B you have to have a starting point of reference which is point A. Then you need to know your direction of travel typically by using a compass. If you knew your exact speed you would not need to know your position. However, a plane traveling in the air (over the ocean in this case) is subjected to cross winds, tail winds, head winds and other forces which do not allow the navigator to accurately determine speed and direction. These can be estimated with some accuracy but the further you go away from the known point of reference the greater the error. So knowing your position (Latitude and Longitude) is critical since the plane has a limited amount of fuel and would need to go from Point A to Point B as directly as possible. During the time Amelia Earheart flew, the only way to determine your position was by using the relative position of the Sun and stars (celestial navigation). The problem with celestial navigation is that it was not that accurate mostly on the order of 0.5 to 1.0 nautical mile (6080 feet) at its best. On cloudy days this method cannot be done and you fall back to time, speed and direction which is an estimate. So if you are trying to find a small island in the middle of the Pacific Ocean that is 0.5 miles wide, it is VERY easy to get lost by missing your target. Today we has modern satellites that can give you your Latitude and Longitude to within a few centimeters. This is called GPS (Global Positioning System).