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

Tuesday, June 21, 2011

Are Aliens All Wet?

Greetings all!  Yes, I know, I'm a day early.  I decided to post today because I've got the day off tomorrow, and I'm spending it with my daughter.  So...let's take a question.

My friend Pam posted the following:

Kelly, why is water the determining factor in finding life on other planets? Doesn't that limit our definition of life to a terrestrial, Earthly paradigm? Couldn't other forms of life exist that require a molecule other than water for survival? 

So I thought I'd talk a little bit about this one (hence the title!), as it's an excellent question (thanks Pam!).  Simply put...yes.  And yes.  It's entirely possible that some kind of lifeform could exist that doesn't require water, and in fact, requires some other compound for survival.  So the question becomes...what would that lifeform be like?  How could we test for it?

You see, all of our physical searches for life beyond our planet have involved robots, which think like a computer.  We can tell the robot to test if certain conditions are met, and it can tell us yes or no.  So what conditions do we program it to look for to see if life is present?  Well...the only life we know requires water.  We know that life forms that require water generally do similar things, like respirate, produce certain kinds of waste products, reproduce themselves and things like that.  These give us parameters to test.  Life based around something other than water is so foreign to us, we wouldn't even know what to begin to test for!  So we make the decision to search for "life as we know it" - that is, water and carbon based.  While this definition limits the kind of lifeforms we are likely to find, it does at least give us a starting point to work from.

So the next question becomes: where can we find water?  Well, water can be found in a whole lot more places than just Earth.  Come visit the museum for our daily 12:30pm planetarium show "Oasis in Space."  It's a beautiful and exciting full-dome program that takes you on a journey through our solar system searching for water.  You'll be surprised at how many places water is hiding right close by!

But let's face it...any life we find here in our solar system is probably going to be minor - something like bacteria, plants, or maybe fish.  When most people talk about aliens, they mean the "take me to your leader" variety...a sentient being that we can carry on a conversation with.  If such highly developed life were present elsewhere in our solar system, we'd probably already be aware of one another.

So what about life on planets beyond our solar system?  There are some 500-plus confirmed other solar systems out there...and the numbers are only going to get bigger.  NASA's Kepler mission is in orbit right now, identifying potential planets, with over 1200 now awaiting confirmation.  Some of them are even approximately the same size as Earth.  Does this mean they are inhabited?  We can't say for sure.  These stars and their attendant planets are hundreds or even thousands of light-years away, and it will be a while before we can figure out if any of these planets have water, let alone support life.  And keep in mind - Kepler is surveying only a tiny portion of the cosmos:

The Kepler mission's field of view (NASA)

So just imagine how many planets there must be in the entire Milky Way galaxy!  That's a lot of planets to check if you're waiting for E.T. to phone might want to put the phone on vibrate and go catch a movie in the meanwhile.

Thanks again to Pam for a great question!  And please folks, feel free to post whatever questions you have in the comment section.  I look forward to hearing from you!

See you again in two weeks!
Carpe noctem,

Wednesday, June 8, 2011

Welcome Aboard!

Welcome to my new blog!  Some of you may already know me from years of Skylights columns in the Daily Press, and from weekly Sky Updates on WHRO for years before that.  Since both of those outlets for astronomy information are now gone, I've decided to try my hand at the 21st century version of such things.

My goal is to update this space every other Wednesday with information about the sky, current events in the world of astronomy and space science, things happening at the Virginia Living Museum, and the occasional (okay, probably more than occasional) sci fi movie or book reference.  I hope you'll find it a fun read, and full of information that you can share and enjoy (ha!  First Hitchhiker's Guide to the Galaxy reference!) with friends and family.

Just to get acquainted a bit more properly, here's a picture of me looking quite commanding at the control desk of the Abbitt Planetarium.  We actually call it the Battle Bridge (and there's your first Star Trek reference!), and it's where I spend a lot of my time.  Come visit sometime!

Actually, come visit this weekend.  This Saturday, June 11, is the second Saturday of the month, and the second Saturday of every month is when the Abbitt Planetarium and Observatory open at night for a Star Party and Laser Light Night.  During this summer, we're expanding the fun with free early evening events in our Conservation Garden, and of course the Wild Side Cafe will be open from 6-10pm.  Observing the night sky is free too (weather permitting), and we'll begin setting up our telescopes around sunset (8:30pm these days).  You're welcome to bring along your own observing equipment if you like, or just drop by and check out the heavens through one of our telescopes.  It's always a fun time.  In the planetarium we'll have Virginia Skies (a live, guided tour of the night sky for that evening) at 7:30pm, Laser U2 (family-friendly) at 8:30pm, Hypnotica (awesome techno music) at 10pm, and finally Pink Floyd's The Wall at 11:30pm.  The shows are $6, or $10 for a double feature (half price for members!).  If you're a 2011 graduate, bring your tassel to the admissions desk and we'll give you a dollar off.

Finally, one thing I couldn't do with Skylights or the Weekly Sky Update was take questions from interested people.  Well, on a blog that's entirely possible!  So please feel free to leave me a comment or a question, and who knows?  You might see your topic show up in future post!

Carpe noctem,