Rikyū on Mercury, or How I Named a Crater on Another World After a Japanese Tea Master
As mentioned in my introductory post, I wrote instrument flight software for MESSENGER, the first spacecraft to orbit our solar system's innermost planet, Mercury. After more than ten years in operation, in 2015 the spacecraft ended its very successful mission by impacting the planet's surface, probably creating a new crater.
But it's a pre-existing crater that's the subject of this post. Since MESSENGER mapped Mercury's surface so well, hundreds of geological features were identified, and naturally each one gets a name. The International Astronomical Union (IAU), the group that infamously demoted Pluto from its full planetary status, explains how features come to be named:
When the first images of the surface of a planet or satellite are obtained, themes for naming features are chosen and names of a few important features are proposed, usually by members of the appropriate IAU task group. Later, as higher resolution images and maps become available, names for additional features may be requested by investigators mapping or describing specific surfaces or geological formations. At this point, anyone may suggest that a specific name be considered by a Task Group, but there is no guarantee that the name will be accepted. Names successfully reviewed by a task group are submitted by the task group chair to the Working Group for Planetary System Nomenclature (WGPSN). Upon successful review by vote of the members of the WGPSN, names are considered approved as official IAU nomenclature, and can be used on maps and in publications. Approved names are immediately entered into the Gazetteer of Planetary Nomenclature, and posted on its web site.
In other words, anyone can propose a name, and if it fits the established theme for the given type of feature and doesn't meet with any objection, the IAU approves the name. The theme established for the naming of craters on Mercury was "Deceased artists, musicians, painters, and authors who have made outstanding or fundamental contributions to their field and have been recognized as art historically significant figures for more than 50 years."
In 2013 when I heard that name suggestions were being solicited for the newly-imaged craters on Mercury and the theme was historically significant artists, I asked around to find out how to submit a proposal to name one of the craters.
It wouldn't be very controversial to say that Sen no Rikyū (1522 – 1591), also known simply as Rikyū, meets the IAU's criteria. He is widely considered to be the "father" of the Japanese Way of Tea, having had the most profound influence on this syncretic art of anyone in history. Tea master for the preeminent feudal lords of his time, he developed many of the utensils we use today, including Raku tea bowls developed in collaboration with a tile-maker of that name. In conjunction with the development of these utensils he cultivated and popularized a simple, intimate, rustic style of tea using Japanese utensils that contrasted with the expensive, ornamental Chinese-made utensils and formal settings that dominated the tea aesthetic until then.
With the name officially approved on June 18, 2013, this crater honors the most influential figure in the history of the Way of Tea. In the image at the top of this post, Rikyū is the crater in the center, just to the left of a slightly larger crater named for the Indian painter Raja Ravi Varma. (In my proposal I suggested that the chosen crater be particularly bowl-shaped; you can judge for yourself whether this 22.4-kilometer-diameter crater resembles a bowl more than any other crater on Mercury.)
