I am pleased to see half of the Nobel Prize in Physics this year go to the first confirmed discovery of a planet orbiting a star like our sun. Since then, evidence for thousands of planets circling other stars has been gathered, including a kind of census conducted by the Kepler orbiting telescope, from which scientists drew this estimate:

There is at least one planet on average per star.[See abstract below.] About 1 in 5 Sun-like stars[a] have an "Earth-sized"[b] planet in the habitable zone.

I have had a longstanding interest in discoveries of planets around other stars. What I remember is how many false starts there were and the period when some scientists said that the lack of confirmed discoveries of planets around other stars meant that there might not be any. In hindsight, excessive optimism about the accuracy of detection methods led to a period of excessive pessimism about the existence of exoplanets.

To me, then, the eventual confirmed discoveries of exoplanets were a triumph of faith over doubt. By faith I simply mean a belief that influences action that, at the time, is based on inadequate evidence. In this sense, we all have to make decisions based on faith very frequently. I emphasize this point in my post “The Unavoidability of Faith.”

I’ll save any discussion of other intelligent life in the universe for another post, but I want to point out something very interesting about exoplanets from the standpoint of popular culture: being literally light-years away, sending probes to exoplanets is dauntingly difficult and might require not only key technological advances, but also enormous patience. But imaging exoplanets, while quite difficult, is something we can hope to do even in my lifetime, let alone in the lifetime of those who are now young graduate students. There is now a growing list of exoplanets that have officially agreed-upon proper names; there is hope that some exoplanets will become familiar to even elementary school students, as the list of their known properties grows.

It is hard to keep up with the onrushing discoveries about exoplanets, but I hope someone will put together a high-quality children’s book on exoplanets that reflects at least everything we know today. Both exoplanets themselves and their discovery are inspiring to me, and I think would be inspiring to many youngsters.