Good morning. Are we alone? Do we live in a Universe that is populated with many, many intelligent species, or are we, as human beings, just the only intelligent life anywhere in the Universe? The last couple of centuries have been a triumph of modern astronomy.
We can now trace back the history of the Universe to just seconds after the Big Bang, when our Universe began. We can watch the Cosmic Microwave Background and map out the structure of the very early Universe. We can track the very first stars that formed in the first few hundreds of millions of years after the Universe was born. We can track the formation of galaxies. We understand nearly everything that there is to know about the way that the Universe was born and the way that the Universe continues to evolve, except for one very glaring exception: life.
We know that in the very first few hundreds of millions of years after the Earth formed, life arose on our planet. We know that from fossils like these, stromatolites, that were formed by the very first organisms that existed on our planet, cyanobacteria. So very quickly, as soon as the Earth cooled off, after its formation, we know that life began here. And even more amazing than the fact that a self-replicating organism somehow came forth, amidst the laws of thermodynamics that govern our Universe, that life evolved fantastic complexity, and, in fact, eventually evolved intelligence. Amazingly enough, we now know that nearly every single star in our galaxy hosts a planet.
And something like one in five of those stars hosts a planet something like the Earth, at just the right distance from the star to have liquid water exist on the surface. But on any of those planets did life arise? Did something similar to what happened on our own planet happened on those other planets? We know that the galaxy is awash in water, it’s awash in organic molecules, and complex chemistry. All of the things that we know were necessary for life to begin on this planet exist in abundance throughout the galaxy.
But did life ever arise on any of those planets? And even more pressing of a question: did that life – if it did arise – did it ever go on to develop intelligence? Is intelligence a common outcome of life? Is intelligence a driven process? Does life proceed towards intelligence for some reason that we don’t yet understand, or is intelligence simply some evolutionary fluke that only happened on one single planet that maybe did develop life? And again, even more interesting, if intelligence does arise commonly, how far can technology progress? How advanced could very advance life become? The Universe is nearly 14 billion years old, and our Galaxy is something like 12 billion years old. So there could be life out there if it evolved intelligence that could be dramatically more advanced than the life that we have here on this planet.
Now, we don’t have any way of directly detecting intelligent life, so we use technology or can use technology as a proxy for intelligence. Here, on this planet, we have been producing technology that has been emitting signals that would be detectable at very, very large distances, well out into the Galaxy for hundreds of years These are things like high-power TV and radio transmitters that we use for communication systems here on Earth, radars that we use to map other planets in our Solar System, or asteroids that we have in our own Solar System, and also laser technology. We don’t do this yet here on our planet, but it’s an amazing fact that if you take our most powerful lasers and our largest mirrors, and you pair them together, for the fraction of a second that our most powerful lasers can produce light, they can outshine the Sun by factors of a thousand and more than a thousand light years away. We have just announced a brand new program that we think is going to be humanity’s best chance ever to answer this question.
It’s called “Breakthrough listen.” It’s humanity’s boldest attempt ever to determine whether or not we are alone as intelligent beings. It’s a 100-million-dollar ten-year project that will use three telescopes to conduct the most comprehensive, sensitive, and intensive search for extraterrestrial intelligence in history. We’re going to use optical telescopes, one called The Automated Planet Finder, that is just about an hour away from here, near San Jose at Lick Observatory, and two of the world’s largest radio telescopes, the Parkes Telescope in Australia, near Sidney, and the Green Bank Telescope in West Virginia, here in the United States. The Green Bank Telescope is one of the world’s largest movable structures, and it is, in fact, the largest fully steerable antenna that we have here, on this planet.
With the telescope like the Green Bank Telescope, we could detect a human-like technology nearly to the center of the Galaxy. We’re going to search a variety of different types of objects. We’re going to conduct a survey of a million stars, about a thousand light years or so off the Earth. We’re going to conduct a comprehensive survey of the entire plane of our Milky Way Galaxy, and we’re going to search a hundred nearby galaxies to see if that very, very advanced life might have developed the necessary technology to transmit at truly extraordinary distances between galaxies. Let’s take a look at how that’s going to work.
Here’s an animation of the Milky Way Galaxy. Imagine that somewhere in the Milky Way Galaxy intelligent life arises and begins to transmit. If they did so, their transmissions would proceed at the speed of light out from their star, for as long as that intelligent life existed. And that would form a bubble of electromagnetic radiation that we might be able to detect here on Earth. But how long do these civilizations live? They might develop life, intelligent life, and then some technology, and a radio signal.