One of the best classes I ever took was the honors astrophysics and astronomy class taught by Jeffrey Bennett at the University of Colorado in the late 1980s and early 1990s.
Professor Bennett is one of those rare scientists who can find the excitement in science and share it with ordinary folks in a way that recreates the way they see the world. Others who had similar gifts include Richard Feynman and Carl Sagan.
I have not spoken with Professor Bennett in many years, but was pleased to find that he just published a new book called Beyond UFOs: The Search for Extraterrestrial Life and Its Astonishing Implications for Our Future. I bought and read it, and was not surprised to find it earning a place next to my personal favorite on this subject, Stephen Webb’s incomparable If the Universe Is Teeming with Aliens… Where Is Everybody? Fifty Solutions to Fermi’s Paradox and the Problem of Extraterrestrial Life.
The reason I’ve always loved the study of space and the potential that intelligent life exists elsewhere in the universe is that it pulls together almost everything we know and want to know. To successfully search for intelligence beyond Earth, we need to understand geology, physics, biology, history, and mix them with a solid helping of imagination. As we search, we realize that it’s overwhelming to think that there are other civilizations, maybe millions of them, and equally overwhelming to think that we’re alone on this pale blue dot in the vastness of space.
One of the unavoidable realizations of studying space is a deeper appreciation for what a nice planet we’ve ended up on, and how important it is that we not ruin it.
Which is why I want to share with you this thought from Professor Bennett’s Beyond UFOs, page 109:
The topic of mass extinctions also holds a cautionary lesson for us. Human activity is driving numerous species toward extinction. The best-known cases involve relatively large and wide-ranging animals, such as the passenger pigeon (extinct since the early 1900s) and the Siberian tiger (nearing extinction).
But most of the estimated 10 million or more plant and animal species on our planet live in localized habitats, and most of these species have not even been cataloged. The destruction of just a few square kilometers of forest may mean the extinction of species that live only in that area.
According to some estimates, human activity is driving species to extinction so rapidly that half of today’s species could be gone within a few centuries or less. On the scale of geological time, the disappearance of half the world’s species in just a few hundred years would certainly qualify as another of the Earth’s mass extinctions, potentially changing the global environment in ways that we are unable to predict.
During past mass extinctions, the dominant animal species — those at the top of the food chain — have never made it through to the other side. Today, we are the dominant species. Perhaps our intelligence would enable us to find a way to survive while other species perish around us, but I wouldn’t count on it. Those who ignore history are doomed to repeat it, and geological history tells us that perpetrating a mass extinction is not in our best interest.
Unless we want to be replaced soon by the next dominant animal species — some type of insect, perhaps — then we’d be wise to heed the lesson of the past, and start doing a much better job of preserving the remarkable biodiversity upon which our survival depends.
