The Stars Go Backwards in Australia
Well, at least for northerners they do. With winter thick upon us and temperatures well below zero the past few days, my mind turned to summer. Then to Australia, where summer has been underway for nearly a month. Sydney's temp...
Well, at least for northerners they do. With winter thick upon us and temperatures well below zero the past few days, my mind turned to summer. Then to Australia, where summer has been underway for nearly a month. Sydney's temp should hit 85 degrees tomorrow.
Anyone who's ever traveled to the southern hemisphere knows how unfamiliar the night sky appears. There's a whole new set of constellations down there. Ones that have been hiding beneath a northerner's southern horizon for years. To see them, we must jump a plane and travel the curve of Earth for hours to coax them into view.
Learning the southern sky constellations of Pavo the Peacock, Octans the Octant or Vela the Sails requires a good map. You can create your own with Stellarium (download at stellarium.org) or sign-up / login at Heavens-Above , select "Change your observing location" under Configuration, scroll down and click "add new". Then select the city of your choice, return to the homepage and click on Sky Chart under Astronomy for a map showing the sky anytime from your new southern city. Another easy option is the interactive map at Sky Map Online .
While you're fathoming those new stars, don't forget to turn around and look at the old, familiar crew. For a vivid sense of having traveled far, there's nothing like facing the northern sky (from whence you came) and seeing all the star patterns completely upside down. Not only that, but the stars, moon and sun all travel "backwards" compared to what we see in the north. Instead of moving from left to right across the sky during the night/day as you face south, they travel from right to left as you face north. Totally nuts!
Likewise the lunar phases. Here in the north, the moon fills out from right to left as its phase waxes from crescent to full. From the southern hemisphere, the direction is reversed. The waxing crescent moon looks like a waning crescent to northern eyes.
It sounds bizarre because we see all those things happening in our southern sky, while for down underers it all takes place in the north. The simple act of turning around reverses the normal directions. If we face south in the southern hemisphere we see the faint south pole star, Sigma Octantis in Octans, and the south polar constellations of Chameleon, Tucana the Toucan and Pavo the Peacock. They pivot around the pole star, albeit a much fainter one, just like the northern circumpolar constellations circle about our north star, Polaris in the Little Dipper.
If only to have our celestial perspective shaken up and altered, I'd advise a trip below the equator for northerners and above it for those down under. And just think. For those in the deep south, Orion's a summertime constellation, one you'd see while swatting flies on a balmy night. I wouldn't mind a piece of that right now.
As for that old saw about water going the opposite way down a bathtub drain in the southern hemisphere, the answer is yes and no. Mostly no, but I'll let Scientific American present the case.