Written by Kelly Herbst, Astronomy Curator for the Virginia Living Museum. Updated every two weeks, more or less.

Wednesday, March 28, 2012

How to Have an Astronomical Vacation

It's easy!  Just look up!

Okay, I'll stop being a smart aleck.  But truly, it is easy to make any vacation astronomical...and looking up really is the key.

We're in vacation mode in my house these days.  Spring Break for my daughter's school is next week, and our family is spending that week in Disneyworld!  It was my Dad's favorite place to go with his granddaughter (and her parents could come too, as long as they didn't try to set any ground rules!), and being there always reminds me of him.  But what has this got to do with astronomy, you're thinking.

If you're already an astronomy buff, you probably know that the sky looks different depending on where you are on the surface of the Earth.  To many folks, this is an incredible revelation.  We don't often think about it, but where you are standing on the Earth can completely change your perspective.

I was asked once after a live sky show in the planetarium how many moons the Earth had.  Since the question came from an adult, I was a bit surprised.  But the lady asking seemed very sincere, so I told her that Earth has only one moon, with the rather unimpressive name The Moon.  She seemed disappointed and told me of her recent trip to Australia, where she saw a large, bright object in the sky, which she thought was the Moon at first.  But something about it didn't look right.  So she thought maybe the Earth had another moon, one that could only be seen from the Southern Hemisphere.

What she was seeing was the regular good ol' was just upside-down.

She looked at me like I had 5 heads.

The Moon as seen from both hemispheres of the Earth.  Images of the Moon from Scientific American (left) and Wunderground (right).  Text and compositing by Kelly Herbst.

But think about it.  The Earth is a sphere, and wherever you go on it, you are standing on the outside of the sphere.  When you travel to the Southern Hemisphere, you have essentially turned yourself upside-down compared to when you are in the Northern Hemisphere.  So things you see in the sky will look upside-down to you!  The lady who had seen the upside-down Moon was amazed...and realized at that point that she had been seeing some familiar constellations, like Orion, upside-down too.

People standing on the Earth.  Notice that someone in the Southern Hemisphere would see things in the sky inverted from the way they would see them in the Norther Hemisphere.  Credit: Kelly Herbst

Now, in Florida, nothing will appear upside-down for us, or even substantially different.  Since we'll be further south than we are in Virginia, we'll see some things on the southern horizon that normally we don't, and the northern horizon will be a bit more hidden from our view.  But even that small change can be worth examining...after all, you never know just what you'll see when you take the time to look up.

So next time you're on vacation, whether near or far from home, spend an evening looking at the sky.  Sometimes a new perspective is just what you need.

Have a great Spring Break!
Carpe noctem!

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