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!

Thursday, March 15, 2012

Sorry, I Was Looking at the Planets

Holy cow, if you haven't been outside lately, get out there tonight.  It's amazing.

I should have updated yesterday, but circumstances beyond my control kept me away from my computer most of the day.  But no matter, one day late doesn't really make a big difference right now.  We've got a planet-palooza underway out there tonight, and there's more to come.

If you've been outside on any clear night in the early evening over the past month or so, you've likely seen two brilliant objects shining in the west.  They are well visible even before the Sun fully sets.  Two bright white shining "stars."  Guess what - those two stars are Venus and Jupiter.  Venus is the brighter of the two.  In fact, it's the brightest object in the sky after the Sun and the Moon.  Jupiter may be the biggest planet in the solar system, but it's much further away (about half a billion miles) and so it looks fainter than our lovely next door planetary neighbor.  These two gorgeous planets have reached their closest approach to one another in our sky, and will now begin steadily moving away from one another.  Keep's going to be a phenomenal sight to watch these planets part from one another night after night.

Venus and Jupiter in the skies of Pennsylvania in February 2012.  Photo by Jack Fusco.  Courtesy Astronomy Picture of the Day.

To see our other planetary neighbor, the red planet Mars, simply turn around 180 degrees from where you see Venus and Jupiter.  Mars is shining a beautiful deep orange on the eastern side of the sky, again, easily visible well before the sky is truly dark.  A bit dimmer yet again than Jupiter, it is still an impressive sight, especially since the color of Mars is so very obvious.  Past its brightest and slowly fading, Mars will gently, and later more rapidly, dim from our view over the next few months or so.  Enjoy it while it lasts!

Still not enough?  Wait a while, until Venus and Jupiter have set.  By late evening, golden yellow Saturn will rise and join Mars on the eastern side of the sky.  The color difference is lovely between Mars and Saturn.  Break out your telescope and you'll be treated to an delightful view of Saturn's majestic rings.  Breathtaking!

Did you miss our March star party?  It was a fabulous night of clear crisp skies and brilliant planets.  But don't worry, we'll be doing it again on April 14.  Jupiter will have sunk too close to the Sun for good viewing by then, but Saturn will consent to rise earlier, joining Venus and Mars to maintain a powerful trifecta of planets in the early evening skies.  Plus we'll be marking the 100th anniversary of the sinking of the Titanic with special shows in the planetairum.  You can get more information on our website.  See you in April!

Now, if you'll excuse me, I gotta get back to those planets.  :-)
Carpe noctem!