## Casas Grandes

Apart from marking out straight roads, the Anasazi were also fanatical about going in a straight line. Chaco indeed has a last surprise in store for us.

Solve the following problem: go to a godforsaken canyon, proceed 100 kilometers north, and if while moving you have deviated from the meridian (compared to the one you started on), then relocate yourself on the original one within an error, say, of one degree or less.

This problem is equivalent to determining one's longitude after moving in a fixed direction, and was indeed the agonizing dilemma that sailors were faced with up to the end of the 17th century. In fact, while it is possible to determine the parallel (and hence the latitude) with solar observations or, at night, by working out the height of the celestial pole, it is necessary to know the local time in relation to the time of a known meridian (for example, that of Greenwich, which is conventionally designated meridian zero) to ascertain the longitude. We have been able to measure longitude with sufficient accuracy (at least sufficient to avoid maritime disasters) only since John Harrison, in the mid-18th century, succeeded in constructing a clock that was accurate enough to be carried aboard ships for reference. Thus, without a clock showing a reference time (or a GPS—namely a position finder based on satellites), there is only one way to solve the problem: not to make any mistakes right from the start, verifying meticulously one's position compared to the previous one on the horizon, exactly as if we had to mark out a road like the Great North Road, but this time for up to 100 kilometers.

Well, the Anasazi did just that. They moved almost exactly along the meridian for 88 kilometers northward, subsequently settling the villages known today as Salmon and Aztec Ruins. Then, they moved far southward, again along the meridian (Lekson 1999)—very, very far. Eventually, 624 kilometers from Chaco, we come across the southernmost settlement probably influenced by the Anasazi, Casas Grandes (also called Paquime), which today is across the Mexican border.

As we have seen, the phenomenon of the abandonment of Anasazi villages has not yet been fully understood. I believe it possible that one of the reasons was not practical, but a question of symbolism: in some instances, in fact, the Anasazi moved to places not because there was more water, or more food, or fewer enemies. They moved just because there was more south, whatever that might have meant to them.

## Telescopes Mastery

Through this ebook, you are going to learn what you will need to know all about the telescopes that can provide a fun and rewarding hobby for you and your family!

Get My Free Ebook