Planet Nine

Planet Nine, the Adler's new sky show, is now playing!

The Search Is On

Included With Museum Entry +2 Pass!

In July 2015, the New Horizons spacecraft gave us our first close look at Pluto, the most famous dwarf planet in the outskirts of our Solar System. The New Horizons flyby was big news, and the pictures it continues to send back to Earth reveal a world far more complex than anyone realized.

Using nothing but their wits (and high-powered telescopes and a thorough understanding of orbital mechanics), these intrepid explorers are making new discoveries about how our Solar System formed—and what it may be hiding.

Follow Mike Brown and his team at CalTech as they uncover dwarf worlds like the remarkably bright Eris; Haumea, an egg-shaped object rotating incredibly fast; and Sedna, whose orbit takes it deep into the far reaches of the Solar System. Is there a new planet beyond these distant objects? We’ll tag along on Mike Brown’s first night searching for the ninth planet at the Subaru Telescope in Hawaii. Join us on the hunt!

Planet Nine collaborators Mark SubbaRao, Patrick McPike, and Mike Brown are the 2017 Vizzie award winners for People’s Choice from the National Science Foundation!

Run Time: approximately 30 minutes

**Please note that the Adler’s Definiti Space Theater will not be playing shows between September 16-November 18, 2019, as the surrounding space will be under construction for a new exhibition. Showings of Planet Nine and Skywatch Live! will move to the Grainger Sky Theater. One World, One Sky will be unavailable. We apologize for the inconvenience, but look forward to sharing a new experience with you coming fall 2019!

Join us on the hunt for 'Planet Nine' with the Adler's new sky show!
Join us on the hunt for 'Planet Nine' with the Adler's new sky show!
Join us on the hunt for 'Planet Nine' with the Adler's new sky show!
Join us on the hunt for 'Planet Nine' with the Adler's new sky show!

Explore these dwarf planets with Mike Brown and his Caltech team in the Adler’s new sky show!


The discovery of Eris prompted the International Astronomical Union to agree on an official definition of “planet” in 2006. Eris is almost exactly the same size as Pluto, yet it weighs 25 percent more. It is also remarkably bright, reflecting 97 percent of the light it receives from the Sun. To put that in perspective, the Moon reflects just 12 percent of the Sun’s rays.


Shaped like a football, Haumea rotates incredibly fast—once every four hours! This object’s fast rotation causes its unusual shape. Were it rotating more slowly, gravity would pull it into a sphere, which is why it qualifies as a dwarf planet even though it isn’t round.


Sedna’s orbit takes it deep into the far reaches of the Solar System, almost 20 times as far as Pluto ever goes. A year on Sedna is 11,400 times as long as a year on Earth! But perhaps the most interesting thing about Sedna is the hints it gives us that there are many more objects yet to be found at the edges of our cosmic backyard.

Join the Hunt For Planet Nine From Anywhere!

Zooniverse Adler Logo

Continue the search for a possible new ninth planet by joining Zooniverse’s Backyard Worlds: Planet 9 project.

Help scientists and researchers classify real celestial objects in our Universe from image artifacts in data from NASA’s Wide-field Infrared Survey Explorer (WISE) mission. No specialized training or expertise necessary. You may come across undiscovered features of our Solar System, like brown dwarfs and low-mass stars—possibly even the hypothesized Planet 9!

Anyone can become a Citizen Scientist—even you!

Accessibility-Symbol-Signs-45057-lgClosed captioning of narration at Adler sky shows (except for Skywatch Live!) is available for guests who are deaf or hard-of-hearing via their personal mobile devices. To access captioning, visit Assistance with this service is available at the box offices or in theaters.

The Adler also provides assistive listening devices for guests that may need support hearing shows and presentations in all three theaters. Guests can learn more and check out the system at either box office. 

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