Science

Although being on a cultural, historic and hedonistic trip, sometimes I cannot but notice some scientific aspects of the things I encounter.

Pigments

Nowadays, the Mesoamerican pyramides look grey and sandy. However, that was not always the case. Apparently, when build they were painted in the brightest colors. One of which was Iron Oxide and sometimes - when erosion was benign - it partly remained:

Note the figure that looks like a cartoon reindeer on the left.

What also strikes the observer's eye are the greenish stones from which the Dominican monasteries are build:

But why, dear reader, art these stones green? You know it, they contain Copper Oxide. Obviously.

Okay, I admit, that might have been boring. Maybe an animal?

Eagle

Some of you might know, that the mighty eagle (águila real en Español, Königsadler in Deutsch) is Mexico's national animal. This is because the Aztecs once decided to settle in a place where they spot an eagle sitting on a cactus and eating a snake. This place happened to be downtown México city. The decision to settle in a place characterized by this event seems a little arbitrary to everyone, however this is how the story is told.

Anyway, since the eagle is such an amazing animal, some studies were done on it. In one very fascinating of these, they attached some sort of tracker to an eagle and followed its flights. Out came this:

I took this picture from an exhibit in Santo Domingo

One can see that the eagle follows the rim of a valley until it picks up thermal upwinds. Once it got into such an upstream, it circles in it, constantly rising. And then continues to look for the next upwind or shoots down to pick up a snake to be eaten on a cactus. Using these streams, the eagle can gain altitude without using a single wing beat. Isn't that fascinating?! Clever guy. Interestingly, paragliding works by the exact same principle.

Also, some pictures from the trip to Oaxaca:

Oaxaca

And updates from Mexico City including a funny dog on a motorcycle

Mexico City