There are certain things that I learned in school that I've never questioned - certain facts that I was taught year after year until they became indisputably true. One impeachable truth was that there are nine planets in our solar system. I'm sure many people even remember a mnemonic used to recall the names of the planets - "My Very Educated Mother Just Served Us Nine Pizzas" is the one that I was taught.
Well, anyone who hasn't been in a coma the last ten years knows that this is no longer quite true. Pluto, the lonely ninth planet at the farthest reach of our solar system, has been kicked out of the club and relabeled a "dwarf planet." And Mike Brown, an astronomer from CalTech, is solely to blame.
Ok, maybe not "solely." But it was Mike and his team's discovery of several large, planet-sized objects in the Kuiper belt outside our solar system that set off a chain reaction of planetary announcements, attempted discovery-thefts, and meetings of the International Astronomical Union (IAU) that eventually led to Pluto's ousting.
Brown brings his intelligence and passion for astronomy to his story. What would seem to be a fairly straightforward memoir, beginning with his schooling and recounting how he met his wife and started a family while working on his career, is spiced up a bit with the revelation that Brown's work was almost stolen by a group of scientists in Spain. You see, in the field of astronomy, the basic unspoken rule is "He who announces it first, discovered it." Basically, if Scientist A finds a planet, and then the next day Scientist B finds it, and Scientist B announces his discovery first, then Scientist B gets all the glory. Brown makes a strong argument for why scientists shouldn't rush into such announcements - it's better to do the research and compile all the facts first before making lofty announcements. That way, there's no need to retract anything - imagine, for example, announcing you found a planet twice the size of Pluto, only to later realize it's actually only half the size. Why not save looking like a greedy fool and wait until you have all the facts?
Another subject that Brown discusses in depth is the definition of the word "planet." In astronomy, it turns out there is no real concrete definition. As the science has evolved over hundreds of years, the word has changed as well. Normally, when most people think of the word, they think of large objects that revolve around the sun. But does that also mean that asteroids should count? Or moons? How large is large? In the end, the IAU had to come to a decision about what counted as a planet and what didn't, and as a result, Pluto's fate hung in the balance along with Brown's discoveries.
Even though I knew the eventual outcome for Pluto, there was still a bit of suspense in regards to the IAU's decisions. I never realized how much I had taken the word "planet" for granted. But I suppose it makes sense since, in the grand scheme of things, we truly know very little about our universe. We're still learning every day, and like with any science, terminology and long-standing "truths" are bound to change.
I've never been very interested in astronomy, but I still found this to be a great little read. It's definitely worth a look, especially if you've always wondered why Pluto lost its status as a planet.
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