The Great Planet Debate:
Science as Process

A Scientific Conference and Educator Workshop

August 14-16, 2008

The Johns Hopkins University Applied Physics Laboratory
Kossiakoff Center, Laurel, MD

Click to view the debate footage

View the debate

Listen to the discussion'

Listen to the conference panel discussions

View the Public Service Announcement

Post-Conference Release: Scientists Debate Planet Definition and Agree to Disagree

Background and Objectives

Top scientists and educators will convene in Maryland this summer to explore a basic, but controversial, question: What is a planet?

The Great Planet Debate (GPD) conference includes two days (August 14-15) of scientific sessions to discuss and debate the processes leading to planet formation and the characteristics and criteria used to define and categorize planets.

An educator's workshop follows on the third day (August 16th) to provide a forum on how the planet debate can be used to spark scientific inquiry in the classroom.

Read this press release for further background on the GPD Conference >

Click here to see the official GPD poster >

An open-to-the-public debate between Dr. Mark Sykes of the Planetary Science Institute and Dr. Neil deGrasse Tyson of the American Museum of Natural History will start at 4:30 pm EDT on August 14th. The debate, which will be moderated by Ira Flatow, the host of Science Friday on National Public Radio, is free to everyone and will be posted on this web site after the event for those not already registered to view the webcast.


Days 1 and 2:

During the first two days of the conference, we will present what we have learned about planetary bodies over more than 40 years of robotic exploration of the Solar System and what we are learning about planets around other stars. The IAU’s dynamical definition of a planet will be presented, as well as an alternative geophysical definition. The utility of each will be debated, along with other potential planet definitions.

Panel discussions, featuring scientists who are prominent in the debate on planet definitions, are planned for Thursday and Friday afternoons. A debate between Neil deGrasse Tyson and Mark Sykes, moderated by NPR's Ira Flatow, will take place starting at 4:30 pm EDT on Thursday and will be posted on this web site after the event. A buffet banquet will follow the debate and is available to anyone who registers for it, even if you don't plan to attend the other portions of the conference. A reception on Friday afternoon concludes the scientific portion of the conference.

Day 3:

The third day of the meeting will be an Educator Workshop to discuss how the question of "The Great Planet Debate" should be treated in schools and how that can be used as a springboard to discuss science as a process, as well as other topics in planetary science.

Call for Papers

Scientists and Educators attending this conference are invited to submit contributed abstracts for oral and poster presentations.

All contributed abstracts must be submitted by email to the SOC Chair (Mark Sykes) at by 8:00 pm (EDT) on Friday, June 27, 2008. Abstracts should be limited to one page, including graphics, tables, and references.

Please indicate in your email which type of presentation you prefer (poster vs oral). Please note that most contributed papers will probably be in the form of posters.

*Abstracts are no longer being accepted*

Visitor Information

Information on lodging, restaurants, maps, and local attractions can be found at:
Note that all visitors are expected to make their own travel and hotel arrangements (i.e., you do not need to contact the APL Travel Office).



planet definition, dwarf planets, pluto, ice dwarfs