Re: If you're in the Antarctica, are you upside down?

Hi Jennifer,
Nice question! I recently moved from Amsterdam, The Netherlands, in the northern hemisphere to Sydney, Australia in the south. I can tell you that some things do appear quite different. For example, the "man in the moon" is definitely upside down compared to how it was in the north. And one of the famous constellations in the night sky, Orion, looks quite different to me-Betelgeuse, the bright red star is at the bottom, the belt of 3 stars runs from bottom right to top left and Sirius, the bright dog star in the next constellation is above Orion, not below. It's all quite confusing!

But to answer your question-no, we are not upside down. This is because of how gravity works and how we define "up" and "down". On earth, the force of gravity pulls everything towards the centre of the earth. We define "down" as the direction that gravity pulls us and "up" as the opposite direction. So my feet down here in Australia are being pulled towards the center of the earth, just as yours are, wherever you live, and in the opposite direction, the sky is still above me. So in that way, up and down are the same for all of us.

Of course, if you could step back and see the whole earth and 2 little people standing on it, one at the north pole and one at the south pole, their heads would be pointing in opposite directions and you might say that one was upside down compared to the other. But remember, down is the way gravity pulls us, so down is really the same for both of them.

By the way, this is why for the astronauts in space, there is no up and down. They are falling freely around the earth and do not experience the pull towards the centre, so there really is no up and down for them. Often they tell stories of watching the earth through the window, then turning around to see their crewmates apparently working "upside down" behind them! But once they turn themselves in the same direction, everything seems normal again. I find that very strange and would love to experience it.

I hope this helps your question,
Neil Saunders