Monday, September 21st, 2015 18:17 Lat: 0° 0’ 0” Long: 91° 37’ 61” W
No matter where you are, you stand in the center. Our perspective marks the focus of our unique personal sphere stretching from horizon to horizon and arcing above and below in all directions. Yet, in a world that is itself a sphere, there must be a place on its surface, which is more central than others regardless of where you stand. There must be a bisecting line that will split a sphere into two symmetrical bowls whose rims, on meeting, re-form an edge-less orb. On Earth, we call this line the equator. Today we crossed this line.
The distinctiveness of the equator has been recognized by the cultures who have lived along its contour well before we had developed world maps, globes, or satellites, and certainly before we came upon the concept of those other traveling spheres called planets. Yet, in the absence of all these tools–and through nothing more than careful observation of daily, seasonal and yearly cycles–we have and we can continue to discover the equator. Even more remarkable, through observation and reasoning, we can glimpse the nature of our planet and its place and motion in the cosmos.
To begin, consider the significance of the single observation that sunlight is not evenly spread across the Earth. At some times and in some locations we are flooded with light, while in others we are dealt nothing but darkness. There is a narrative to be read in this unequal distribution and in the patterns that separate light from dark. Pay attention and you can begin to see the world from a single point wherever you are. Shadows tell the story of the sun’s path, the points of sunrise and sunset identify the seasons, mindful stargazing reveals the distance separating you from the equator. You can experience all this in your own life if you look closely. Pay attention to the sun as it rises and falls along its daily journey and you’ll notice morning’s long shadows shorten until the sun reaches its noonday zenith then grow again as evening comes. Trace the shifting points of sunrise, zenith and sunset throughout the seasons and you’ll notice that the they all appear to migrate along the horizon like Canada geese— traveling further south in the winter, and north in the summer. Measure the angle between horizon and the North Star, Polaris, (or, if you are in the south, the Megallanic Cloud of the Southern Cross) and you will have determined your latitude.
Weave all of these clues together and you can begin to see the underlying cause-and-effect relationships which reveal the secrets of Earth’s position and motion in space: The sun’s daily journey is a clue to planetary rotation. The position of sunrise zenith and sunset point to the tilt of the Earth’s axis and hint also to one’s latitude, which can be pinned down more fully by looking at those special points in space lying directly above the poles.
Wherever you are there is a compelling geographic story to be read within the elements of the everyday. Yet, there are special times (in special places) when you may experience the exceptional—if you take the time to look. Today was one of those times.
Across the Earth, the sun reaches its zenith (its highest point) at noon because the planet’s rotation has presented that locale—and all others of similar longitude—directly to the sun. The wandering nature of sunrise and sunset that you observe exists due to the Earth’s tilted axis, a twenty-three and a half degree bow that it makes to the sun or to space depending upon the season. Twice in the Earth’s yearly revolution around the sun its tilt is perfectly perpendicular to the sun’s rays and light is cast directly upon the equator. These are the autumnal and vernal equinoxes (also known as the first day of fall and the first day of spring respectively). If you are on the equator, and it is the equinox, and it is noon. This is what you get*:
What is special—and peculiar—about this photo (besides how funny I look of course)? Look closely. Read the clues. Can you tell?
*Minor caveat: the perfect alignment of date, time and position to allow me to be exactly on the equator at noon exactly at the equinox (this year, falling on September 23rd at 2:22am Galapagos time) was impossible given our journey. This picture was taken at noon (exactly) thirteen nautical miles south of the equator 37.5 hours prior to the precise equinox. With all this said, I’d say this is both incredibly close and surely close enough 🙂