Astrophysicist Dr Andrew Siemion has the dream job of any sci-fi fan: finding aliens. He serves as the Director of the UC Berkeley Center for Search for Extraterrestrial Intelligence (SETI) Research and is one of the leaders of Breakthrough Listen, the largest ever scientific research program aiming to find evidence of civilizations beyond Earth. Via SETI@home, anyone interested can keep tabs on their research. At the 2018 SHIFT Business Festival, Dr Siemion gave a talk about Intelligent Space, discussing aliens and what we can learn from them.
Dr Siemion’s work, like any research on life outside Earth, is fundamentally based on the Drake Equation. The equation, created in 1961 by Dr Frank Drake, estimates the number of active, technologically advanced, communicating civilizations in the Milky Way. In spite of its age, the Drake equation continues to be a central tool in the search for alien intelligence, because it outlines an effective roadmap of what we need to learn and look for: manifestations of extraterrestrial technology, or technosignatures.
The detection of civilizations intelligent enough to produce technosignatures began through trial and error. In 1924, researchers detected low-frequency radio signals that they thought came from Mars, but in the end the signals were found to have come from Earth. Similarly, the Wow! signal of 1977 was long held as possible proof of alien life, but today, the scientific consensus is that this, too, was due to radio interference from Earth.
Perhaps surprisingly, radio signals are still the target of observation. It is believed that if an intelligence were trying to let us know about their existence, using radio waves is the likeliest way they would do it. Breakthrough Listen focuses on passive listening, meaning that the researchers monitor radio signals that are coming towards Earth.
Even though many things in our search for the aliens out there still remain the same as many decades ago, Dr Siemion reminds us that we have also learned much. For instance, today we know for a fact that nearly every single star in our galaxy hosts a planet – and about one in five stars hosts a planet resembling ours. Breakthrough Listen is only one part of the larger Breakthrough Initiative; Breakthrough Watch aims specifically to identify and characterize Earth-sized, rocky planets within 20 light years of Earth.
Along with our scope of knowledge, also our technological capabilities have increased. One of the challenges in using radio signals to find alien life is that we have no way of knowing which frequencies they might be using, so researchers have to tune into multiple channels to try and identify signals that appear artificial. To help with this, Breakthrough Listen has deployed dedicated hardware to the Green Bank Telescope in West Virginia (GBT). These on-site spectrometers can scan billions of radio channels at once.
We also now have telescopes more powerful than ever, like the GBT and the Parks Telescope in Australia. With these and through collaboration with other research programs, Breakthrough Listen has recently been able to collect more data than ever before. This data is being released into a public archive, available for download so that those with technical expertise can contribute to the creation of algorithms and analysis techniques to make the most of the vast new dataset – effectively crowdsourcing the search for alien life!
The quest for extraterrestrial intelligence continues to lead to new discoveries about the universe around us. Around the time we were enjoying this year’s SHIFT, the Parks Telescope was redirected towards and interesting object: BZ509, which may be of interstellar origin. The first object determined to have traveled from another system is Oumuamua, or I1. It is a cigar-shaped interstellar asteroid detected by GBT in December 2017. At that time, Oumuamua was rapidly moving through our solar system. Whether artificial or not, it was identified as a highly interesting target for Breakthrough Listen, as it could provide important information about the conditions of its place of origin, perhaps even giving some hints about the probability of intelligence there.
It is possible that the exchange of objects between planetary systems is much more common than we think. Theories like panspermia postulate that life is transported between stars by comets, asteroids and other travellers, and even that artifacts of a distant civilization may have made their way to our solar system at some point. “After all, if human beings are capable of sending our technology to other stars – as intended by the Breakthrough Starshot program – why couldn’t another intelligent civilization do the same thing?” (Breakthrough Initiative).
When considering the exchange of objects or signals between star systems, one must bear in mind the distance in space – and the time it takes to travel such distances. Any indication of an alien civilization will be from the distant – as in some 100,000 years distant – past of that civilization. However, what is past for them is most likely future for us, as we have only been a technological species for a tiny moment.
So it follows that if we find signs of life having evolved in another system and evidence of that life having developed intelligence…then observing that life just might teach us something about our own future.