Tuesday, March 23, 2010
And the answer is...
...Ceres and Eris, (along with Pluto, Haumea and Makemake), make up the five dwarf planets within our solar system. Why is that significant? Well, Ceres is actually the smallest known dwarf planet, and it resides in the asteroid belt between Mars and Jupiter. Eris is the largest known dwarf planet in our solar system, and has an orbit more distant than Pluto's. There's a great image of the three of them here.
I have a poster from National Geographic in my cube at work that has some facts and relative size depictions of the 8 planets in our solar system along with 3 of the 5 dwarf planets - Ceres, Pluto, and Eris. This poster was put out shortly after the IAU decision in 2006 to define what is and isn't a planet. That was nice of them since every other space poster since the 70's depicting 9 planets just became outdated.
That decision wound up with Pluto being demoted, and caused some public outcry. People, it seemed, were very attached to Pluto as a 9th planet. Well, that's really an understatement. Some people (including astronomers) were actually outraged at the reclassification. There's even a petition website. In Illinois last year the state senate voted that Pluto was to be a planet again for a day. Pluto is the underdog, and people like to root for an underdog. Pluto has 3 moons for goodness sakes! It's not a planet? Who says?
Well, actually some really smart and very well reasoned people said, "look, we weren't right originally". We need to alter our thinking to go further. We need to shift our paradigm a bit. There are other bodies in orbit around the sun - some larger, and some smaller than Pluto. It makes more sense to group Pluto into this other classification with these four other celestial bodies.
I like having that poster in my cube because it is a daily reminder that often people get caught up in their way of thinking and can't break free. And then one little piece of extra information can alter their view of a topic, or push someone to a different way of looking at the world. Those are the kinds of stories that energize me. Being open to learning something new or different. Being willing to admit a mistake. Knowing when to hold on and when to let go. We didn't lose a planet with Pluto - we gained Ceres and Eris and a bit more understanding.