Our friend Bill from the Mid-Hudson Astronomical Association came to visit again. He had a lot of fun videos and simulations on his computer. We started off our meeting with a game. We were the International Astronomical Union (IAU) and we had the task of reclassifying everything in the solar system, using scientific data. Each group had to decide what information they would use as criteria. We had three groups and we had two different approaches. One group classified objects according to what the orbited (i.e. Sun vs. planets.) The other two groups classified objects by their overall composition.
This was an activity from the Astrophysical Society of the Pacific. You can download it from their webpage: http://mintaka.sdsu.edu/projectastro/resources/solarsystem_sort_activity.pdf
Then Bill shared with us some things he learned in a course he is taking about the Solar System. The "Bulls Eye" Model divides the Solar System into zones by object characteristics and Pluto is out of place as a planet. Here's the diagram:
That was Bill's last visit to our class. We'd like to thank him. We will miss getting to see him!
1 comment:
I hope you also bring in someone from the astronomy community who supports classifying Pluto as a planet.
It should be noted that the IAU’s controversial demotion of Pluto is very likely not the last word on the subject and in fact represents only one interpretation in an ongoing debate. Only four percent of the IAU voted on this, and most are not planetary scientists. Their decision was immediately opposed in a formal petition by hundreds of professional astronomers led by Dr. Alan Stern, Principal Investigator of NASA’s New Horizons mission to Pluto.
Stern and like-minded scientists favor a broader planet definition that includes any non-self-luminous spheroidal body in orbit around a star. The spherical part is important because objects become spherical when they attain a state known as hydrostatic equilibrium, meaning they are large enough for their own gravity to pull them into a round shape. This is a characteristic of planets and not of shapeless asteroids and Kuiper Belt Objects. Pluto meets this criterion and is therefore a planet.
For more on why Pluto is a planet and worldwide efforts to overturn the demotion, visit my Pluto blog at http://laurele.livejournal.com
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