I had an astronomy class last night. I learned that the hit of a 10 km asteroid on this planet can wipe out all humanity, that a 5 km one can destroy a continent, and that a 600 mts meteorite can destroy three countries. I also learned a bunch of stuff about black holes, supernovas, when the universe will collapse, and an Earth-like planet called Kepler-186F. Also, that a meteorite of 1 mt smashed a car in Russia, and that there have been more than 1000 meteorites falling on this planet. Oh! The most important part: There is a chance of a 600 mts meteorite falling on this planet in the year 2036.
My eight-year old teacher takes a deep breath and says: “I really hope that meteorite doesn’t fall here”.
I did not take that comment lightly. I used to have similar fears when I was a kid, but instead of being afraid meteorites falling in the future, I got a bit obsessed about earthquakes. That fear was very real; I even remember making scape plans in the building where I used to live. More than thirty years later, immediately after living through the 8.8 Richter scale Earthquake in Santiago, Chile, I got a strange feeling of relief. Finally, the Earthquake had happened.
When my kid made that comment, I was tempted to tell him, “that’s not going to happen, don’t worry”. Instead, I asked him: “What’s the probability of that meteorite hitting the planet in 2036?” Without thinking twice, he answered: “2.7%.”
I thought about it for a moment, and asked him, “Do you know what a percentage is?” His answer was, “no”. Alright then, we had some space to maneuver. I roughly explained to him the concept of percentages, and he got it. Just then, I allowed my self to tell him, “there’s nothing to worry about. There’s 97 scenarios without meteorites colliding planet Earth, against 3, that include that meteorite hitting the planet”. He smiled, and then I knew he’d gotten it.