No, It’s Not upside Down!
For the past week we have not seen the Sun much – even nights have been cloudy, and the temperature has been below freezing for more than a week. So combining those conditions with thoughts of warmer climes, and recent correspondence (aka e-mail) with a long-time friend living in New Zealand brought back memories of a trip I took with my wife, Sue, to New Zealand to attend an Astronomical Conference in New Zealand.
Remember the 80’s song by Men at Work
that asked the musical question “Do you come from a land down under?” That lyric gained new meaning for me while at that conference. I was politely corrected when I said that I came down to New Zealand. “No, no,” my hosts said, “You came up to New Zealand.”
Have you ever wondered why we refer to folks from Australia and New Zealand as being from down under? How did their neck of the woods become down under and ours, conversely, up top? How is it that north is assumed to be at the top of the Earth and south at the bottom of the Earth? For that matter, is there really a top or bottom to the Earth?
Hold a ball in one hand. Touch the top of the ball with your other hand. Directly opposite this point is the bottom of the ball. Turn the ball around in random directions a few times and again touch the top of the ball. Turn the ball around in random directions a second time and again touch the top of it. Did you touch the same spot on the ball each time? Was the bottom the same each time? So where would the top or the bottom of the ball be? Think of the ball as the Earth and each of the spots that were the ‘tops’ as different places on the surface of the Earth.
Now try this:
Nosotros casa es su casa
Take either a reticulated Earth globe or a globe that can be taken off of its mounting and set it in a large cup or bowl that will serve as the base. Adjust the globe so that your location on Earth is at the top. Mark this location on the globe with a straight pin or matchstick held with putty. Next, rotate the base so that globe’s north pole is aligned with true north and it’s south pole with true south. The Earth globe is now positioned with respect to the Sun exactly as the Earth is positioned in space with respect to the Sun. (Note that the shadow of your marker will mirror the shadows of all other objects cast on Earth with regards to compass direction.) From this ‘space’ perspective, you are clearly at the top of the Earth. Notice what point on the surface of the Earth is directly opposite your location, or at the bottom of the globe.
If there is land at that location, imagine your counterpart doing this same activity. Who do you think your counterpart would consider to be at the bottom? Imagine doing this for other locations around the Earth. What does this tell you about where the top and bottom of the Earth is?
Your answer would have to be based on your frame of reference (you are on top wherever you are). This, unfortunately, is not the traditional way of looking at things around the globe.
“Be Careful Opening the Overhead Bins”
It has been a common and accepted convention to think of north as being at the top and south at the bottom. This thinking has established our perceived understanding of our place on the Earth and the vocabulary associated with this line of thinking.
This Northern Hemisphere–bias has even influenced how many astronomy books depict the Moon and constellation patterns. To someone from south of the equator, constellations and Moon phases are upside down according to the Northern Hemisphere–based star maps.
So, is there actually a top or a bottom to the Earth? It’s up (or down) for you to decide.
Thanks to Eric Jackson for planting these ideas in my head!
Click here to go to the Qué tal in the Current Skies web site for more observing information.