Birth of a Planetarium Exhibit - Themes

This is part three of an ongoing series about the overhaul of the Fiske Planetarium .  For the other parts of the series, click here.

The Universe is a big place, chock full of an unimaginable variety of phenomena.  Everywhere we look, something new and exciting is happening.  So, when it comes time to pick what's important out there, we're faced with a big task.  How can we best boil down the vast intricacy of the cosmos into a clear, digestible message?

The cosmic microwave background is the oldest light observable in the Universe.  What does it tell us about the course of astronomical exploration?  (Image credit: ESA)

The simple answer is that we can't - there is no single driving force which shapes everything we see.  Instead, I've chosen to highlight a number of ideas which carry through large (figuratively and literally) swaths of nature.  At this point, they are: 

  1. Water and life: The search for life outside of Earth drives our exploration of nearby planets and moons as well as piques our interest about the exoplanets which now seem to teem in the galaxy.
  2. Active surfaces: The surfaces of the planets, moons, and stars we've observed are far from static.  From the geysers of Enceladus to dust devils on Mars to "earthquakes" on the Sun, environments in space are in constant motion.
  3. Electricity and magnetism: Much of the normal matter in nature exists not in electrical balance, but in a charged or excited state.  These atoms and molecules are thus slaves to the electric and magnetic fields inherent in most spinning objects.
  4. Gravity: From the orbits of planets to the collision of galaxies, gravity is the dominant force on cosmic scales.  It binds together the matter which comprises all the large objects in the Universe. 
  5.  Origins: What was the Big Bang?  Why did our universe form as it did?  Astronomy and fundamental physics intersect at the birth of the cosmos and, more than thirteen billion years later, we're still searching for clue about how it all came together.

Do these five themes cover every all possible natural phenomena?  Of course not.  But, from biology to chemistry to geology to physics, these ideas do  span the breadth of scientific inquiry.  The study of the Universe, after all, is just one (rather large!) aspect of the study of nature.

Of course, just as it's wrong to think that these themes cover everything, it would be a mistake to believe that every phenomenon slots easily into only one category.  Take, for example, the cosmic microwave background (CMB).  The CMB is the oldest light in the Universe - it was emitted just 380,000 years after the Big Bang when the Universe first became transparent.  Sounds like Origins is the right theme, doesn't it?  But every blip and blemish in images of the CMB, like the one seen here, represents a small fluctuation in density of the early cosmos.  Gravitational instabilities in the dense regions collapsed them into the structures which would eventually become galaxies.  So Gravity would be a plausible theme, too.  In the end, I went with Origins, because at this point there are a lot more examples of gravity to choose from.

As the exhibit matures, these themes are sure to develop.  Perhaps we'll even need to add another.  But focusing our exploration of the Universe down to a few key ideas will help guide visitors through what amounts to centuries of discovery.