Why is Pluto no longer a planet? Thanks to the International Astronomical Union (what a mouthful!) declassifying Pluto as a planet in 2006, this is yet another question our kids can ask that some of us might not know how to answer. This is when it’s good to be a Chicagoan because we have places like Adler Planetarium to turn to when we need our kids to think we’re all-knowing. Read on to hear how their temporary exhibit What is a Planet? is providing simple answers to a big question.

Adler What is a Planet 6

Our definition of a planet has changed a lot in the past 500 years. Actually, there wasn’t an official definition until 2006—can you believe that? The word itself has been used along the way to describe the Sun, the Moon and asteroids. And Earth, our most favorite planet of all, wasn’t even considered a planet at one point.

Adler What is a Planet 4

The mission of the exhibit
Who knew people were so passionate about Pluto? They are. And scientists found that out when they demoted Pluto, the last planet to be discovered, from a full-fledged planet to a dwarf planet. People, kids in particular, felt Pluto was being picked on because of its meager size. Letters were written to the voting body who made the decision in defense of this little guy, but its label remained the same – dwarf planet. The purpose of the What is a Planet? exhibit is to explore the reasons behind developing the new definition of what makes a planet and explain why Pluto just didn’t fit the bill. We could give you the answers, because of Adler we know them, but we’ll let you explore the exhibit yourself to find out.

Adler Planetarium Artifacts

Why we love it
You can walk in virtually clueless about how astronomers classify planets and within minutes have a pretty solid understanding of the definition. And, more importantly, be able to explain it to your littles when they ask. What’s also cool is you can walk in with very little interest in the topic and walk away with a newfound appreciation for the world of astronomy—which, the same could be said with any exhibit you visit at Adler. It’s a pretty fantastic resource we have at our fingertips.

Adler Should Pluto be a Planet

Things to look for
Visitors can cast a vote on how they feel about Pluto’s demotion in an interactive voting poll that shows results in real time. Also, explore artifacts from the Adler collections that illustrate the ever-evolving definition of a planet.

Don’t miss out!
Take note! What is a Planet? is only on display from now through August 18, 2019, so pencil in time soon to check it out!


While you’re there
Save time for a visit to the Community Design Lab. Visitors can test different materials to find out which would survive the journey to 100,000 feet above Earth’s surface, build a DIY telescope-mount for smartphones and become an instant astrophotographer by testing it on real telescopes and explore daily scientific challenges developed by Adler experts. With 600 ounces of marshmallows, 10,000 popsicle sticks, 12,000 yards of duct tape, 120 ounces of shaving cream and a steady supply of bubble wrap and cardboard, the design possibilities are endless!

Other ways to explore Adler
Take your fun to the next level by scheduling an Astro-Overnight where kids can participate in hands-on activities and see sky shows. Your kids will be over the moon if you sign them up for summer camp to discover new worlds, engage in eye-opening experiments and play next to Lake Michigan.

What are you waiting for? Show your kids science can be fun!

Adler Planetarium
1300 S. Lake Shore Dr., Museum Campus
Online: adlerplanetarium.org

— Maria Chambers

Photos courtesy of Adler Planetarium