Discovering a new planet or killing an existing one?

Before 2006 people didn’t even consider it conceivable that the Solar System could be changed. Until the day the International Astronomic Union determined that Pluto would no longer be a planet. And there is one responsible person for that resolution: Mike Brown. I don’t mean that he personally wanted to downgrade Pluto from the rank of planet to that of “dwarf” planet. But he unwittingly influenced the fate of Pluto and changed people’s idea of what a planet is.

Pluto could still be a planet if it had not been for a bet dating back to 1999. Yes, a bet, you understood correctly. It was a bet between Mike and one of his colleagues at the California Institute of Technology. Mike was convinced that in the next five years an astronomer would find a new planet, bigger and further away than Pluto. And he was confident enough to think he would be the one.

So, every night for more than five years, Mike and his assistants Chad and David aimed their telescope to the heavens. They used to take several photographs one after the other, looking for something moving. Until they came across a body moving very slowly, meaning that it was far beyond Pluto. It was the furthest object they had ever discovered, and also the brightest one. With this information, they immediately assumed that this object had to be very, very massive.

But astronomy is a science. Every discovery needs data to be proven, and data needs time to be collected. No estimate is allowed. This is a very important lesson I learned from this book: never draw conclusions too early! It was not the first time for Mike and his team to overestimate the dimensions of celestial objects.

“There are two types of bodies that can reflect a lot of sunlight: the big ones covered with earth or the smaller ones and covered with snow or ice, and they reflect the same amount of sunlight," Mike wrote in the book. This is probably the hardest aspect of astronomy. There are so many variables to consider and objects are so distant from Earth that everything is much more ambiguous. But this is also the reason why so many people, including me, are fascinated by this discipline!

To decide which was the case, Mike and his colleagues took pictures of the object with the Hubble Space Telescope. The result was a surprising: the object they had discovered was just about the same size as Pluto. Mike’s discovery was completely scaled down, but it had tremendous implications on the history of astronomy anyways.

This discovery was not significant in the way that it changed the Solar System as it is. It was significant because it changed the Solar System as we think of it. The Solar System has been, is and will always be the same in its composition. But this brought the debate on Pluto to a critical point. If the new body was classified as a planet, where would the border of the Solar System be? And if it was not, why would Pluto be considered a planet, since the two bodies have roughly the same diameter?

After a long discussion, the International Astronomical Union opted for reducing the number of planets to eight: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. People wouldn’t use anymore the typical “My Very Educated Mother Gave Us Nine Pizzas” to remember the name of planets. They would just replace “Nine Pizzas” with “Nachos”. And I, as an Italian citizen and a pizza lover, felt very disappointed with it. How can you even compare pizza to nachos? This itself would have been a solid argument to keep Pluto in the category of planets, don’t you think so?

By the way, Mike believes that the IAU’s decision was right and he was not even too sad for the loss of his planet. Even if he could have been the only living discoverer of a planet. But this is the real purpose of science. Not pursuing personal gratification, but helping people to have a better knowledge of the universe.

Overall, this is a book that blends together both humanity and science, feelings and concepts. But most importantly, it gives the opportunity to realize that nothing is fixed, that everything can change at any moment. You must be aware that you have the ability to change your life and you should never give up. And even if it doesn’t turn out to be the outcome you desire (in the same way as Mike’s discovery didn’t result to be a planet), you have to be proud of yourself.