“Whether we’re alone in the universe depends on whether alien societies overcame the climate change their advances created, says astrophysicist Adam Frank at the University of Rochester who argues that argues that we have never been in a better position to answer question of are we alone , thanks to a revolution in our knowledge gained by powerful telescopes like Hubble and space probes like Voyager. Indeed, the chances that there has never been another civilization in the universe are as low as one in ten billion trillion. But whether there is still one out there today is a more complicated question.”
Speaking from his home in Rochester, New York, Frank explains to Simon Worral in National Geographic (and to Joe Rogan in the video below), how, after being rejected because of its New Age connotations, the Gaia Hypothesis has gained acceptance in the scientific community; how climate change is an inevitable feature of civilization building; and why we need to grow up as a civilization if we are to survive climate change.
The first revolution is that we have been visiting other planets in our solar system. We have now sent probes to pretty much every kind of object in our solar system, including Mars. And from this we’ve learned about climate and how planets work in a generic sense. There’s an app you can pull up that will give you the weather on Mars. We have climate models for Mars, Venus, and Saturn, and we know a huge amount about climate as a generic planetary phenomenon, not just on Earth.
The second revolution is studying the Earth’s history going back 4.5 billion years. We have been able to unspool in some detail the long history of the Earth and its life co-evolving over that time. We see that Earth has been many different kinds of planets, sometimes a snowball world, sometimes a hothouse world without ice. In the beginning there were no continents; it was pretty much a water world.
The last big revolution is the exoplanet revolution. When I was a graduate student in 1985 I did not know whether there were any stars in the universe with planets around them. Now we know that the universe has ten billion trillion planets that are in the right place for life to form. Those three revolutions completely changed not only how we think about life and planets, but also leads us to think very differently about exo-civilizations.
The big question we all want to know is are we alone? What’s your view, based on the evidence?
In 2016, Woody Sullivan and I wrote a paper where we took all of the data from the exoplanet revolution and asked ourselves: What can we say with this data about exo-civilizations or aliens, as people like to call them? With science you have to tune the question to the data you have. And the question we could answer with that data was: How bad does the probability of forming a civilization on a random planet have to be for us to be alone, for us to be the only time in the entire history of the universe that there’s ever been a civilization? That number is 1 in 10 billion trillion.
That number tells me that the only way that we can be the only civilization in cosmic history is if the odds are that low or lower. As long as there’s a probability larger than that, then it has happened before. So unless nature is really perversely biased against forming civilizations then there have been others.
Whether there are others in existence today, I cannot answer. It all depends on this important factor in the Drake Equation, the average lifetime of a civilization. You could have planets creating civilizations all the time, but if nobody makes it to more than, say, 200 years, then right now we would be living in a sterile galaxy. We can say that, yes, there have probably overwhelmingly been civilizations before us. The next step is, does anybody last long, particularly when climate change is going to be a natural consequence of civilization-building?
Image credit top of page: With thanks to Robin Florie at Art Station