Black Triangle sighted near here: 35.202187, -101.835552
Plugging the coordinates of the clue into GoogleMaps yields the address 299 SE 11th Avenue, Amarillo, Texas. Looking at the street photos in this locale, one sees not far off a black truncated pyramid of a building, currently housing Channel 7 television, which one might think could serve as the "Black Triangle" of the clue (although that's not it, as you will see). Amarillo also has the distinction of possessing the only facility for nuclear weapons assembly and dissassembly in the United States, owned by Pantex; surely this could be a plot point in an apocalyptic, highest-stakes-possible thriller -- such as The Lost Symbol could well be.
However, as it turns out, the solution to this clue involves, not the location mentioned in the clue, but the identification of the "Black Triangle" itself.
According to a long-standing and consistent set of rumors, the SR-91 Aurora is a hypersonic reconnaissance aircraft, developed for the U.S. Air Force to replace the famed SR-71 Blackbird. (An artist's conception of the Aurora aircraft is shown above; click for a larger image.) Hypersonic aircraft would be among the ultimate surveillance technologies.
As it happens, one explanation that has been given for years for UFO sightings is that at least some of them are glimpses of test flights of secret high-performance aircraft. In fact, as a reader on this blog -- Machine.Elves -- noted in a comment on another post that, some time ago, there was a famous sighting in Amarillo of evidence of the Aurora aircraft. This alerted my trusty research staff -- directed by, and entirely composed of, my brilliant imzadi y esposa, Kathleen Koltko-Rivera -- to discover Sandy Tamayo's comment on the Dan Brown Facebook fan page, noting that:
On March 23, 1992, near Amarillo, Texas, Steven Douglas photographed the "doughnuts on a rope" contrail and linked this sighting to distinctive sounds. He described the engine noise in the May 11, 1992, edition of Aviation Week & Space Technology.
Thus, the "Black Triangle" of this clue refers to a glimpse of the Aurora aircraft, in Amarillo, Texas. As Machine.Elves also pointed out, what I call the more fringe-y part of the conspiracy community claims that Black Triangle aircraft are being used to further the aims of a grand conspiracy that is attempting to create a New World Order (a phrase which is mistakenly claimed to be the translation of "Novus Ordo Seclorum" on the reverse of the Great Seal of the United States; see my comments on Clue #35). (And a great big tip of the hat to Machine.Elves for bringing this all to my attention, with thanks to Sandy Tamayo.) This solution, the Aurora aircraft, was confirmed by Frank Nelson, an executive at Doubleday, Dan Brown's publishers.
It's not hard to see how this might work into The Lost Symbol. As I mention above, the Aurora aircraft would be cutting-edge technology for surveillance -- for either the forces of good or evil. In addition, however unlikely it would seem to me to do this, the Aurora could be used to transport Robert Langdon around the country at Mach 5.
Incidentally, just to complicate matters further, it is worth noting that there is another way in which the term "Aurora" might work into The Lost Symbol. AURORA is also the name for a cryptographic algorithm, that is, a mathematical system to create a coded message. Developed by Sony and scientists at Nagoya University in Japan, the algorithm is said to have certain weaknesses. This is interesting, given that the Twitter clues for The Lost Symbol include several instances of codes that failed, that is, codes that were broken. These include the Enigma machine (Clue #46) and, especially, the code used in the Babington plot (Clue #15 and Clue #95).
[The image of the artist's conception of the Aurora was created on Jan. 6, 2008, by "Henrickson" with contributions from Bret Danielson. It was obtained from Wikipedia, and is used here under license from the Creative Comons Attribution--ShareAlike 3.0 License, and the GNU Free Documentation License.]
Copyright 2009 Mark E. Koltko-Rivera. All Rights Reserved.