Tag Archives: lunar phases

Do Things Really Look Different From "Down Under"?

I wish I could answer this question from experience. When I was ten years old, a neighbor lent me a book called The Complete Adventures of Blinky Bill – Blinky Bill was a koala – , and I fell in love with Australia. It would be truer to say I fell in love with the stories about Blinky Bill and his marsupial friends, because they were all I knew about Australia. It’s a good book. It made me want to go off and explore Australia immediately – a desire which, regretfully, I have never had the opportunity to indulge. Still, the Land Down Under has always had a special place in my imagination since then.

Most of us have heard that water goes down the drain one way (counterclockwise) in the Northern Hemisphere and the opposite way (clockwise) in the Southern Hemisphere. This is supposed to be due to the Coriolis Effect. To be very brief, the Coriolis Effect is the way the Earth’s rotation makes large bodies of fluids – like water and air in the oceans and the atmosphere – start to spin. The Coriolis Effect is what causes hurricanes to form. But it does not affect the way water goes down a drain in either hemisphere. The amount of water in a bathtub or toilet is too small to be affected by Coriolis forces. You can prove this yourself by filling the sink a few times and watching it drain. Sometimes the water will start to rotate, and sometimes it will just drain away with no spinning motion at all. You can run a finger around the drain clockwise to start a clockwise rotation, or make it drain counterclockwise if you like. It will not change due to the Coriolis Effect.

Tropical cyclone storms are another matter. These rotating storm systems (called “hurricanes” around the Americas and “Typhoons” around Asia) form because of the Coriolis Effect, and they turn counterclockwise in the Northern Hemisphere and clockwise south of the equator. The huge amounts of air and water involved are affected by Coriolis forces, unlike draining water in a sink or tub.

What else looks different in the Southern Hemisphere? If you watch the moon change phase throughout its cycle, you will notice that the change happens from right to left. (Click here for a really good animated model.) In the Southern Hemisphere, the pattern is reversed: the phases change from left to right! This would seem very strange to me. Maybe someday I will get to visit Australia and find out for myself!

Another thing that looks different from the Southern Hemisphere is the starry night sky. Since the Southern Hemisphere looks out on space in the opposite direction from the Nothern Hemisphere, the field of vision is completely different. Near the equator, the view from either hemisphere is most similar, but the difference increases the farther you go toward either pole. (Click here for a great map of the stars from both hemispheres.)

It will never be the same to see something online as it would be to see it with your own eyes. I have always enjoyed traveling and hope to keep discovering and exploring new places as long as I live. St Augustine once said, “The world is a book, and those who do not travel read only a page.” How true.