SETI and the search for extraterrestrial life

The quest to determine whether or not humans are the only intelligent life forms in the universe is ongoing. Though there has been no definitive proof as of yet, experts are still searching. Chenoa Tremblay, a project scientist at the Search for Extraterrestrial Intelligence Institute, delivered the keynote address during the Math in Space and the Unbreakable Bonds of STEM event hosted at Texas State on in April.

“Are we alone in the universe, is a question that I've been exploring through parts of my career over the last few years, and it's a question that human races supposedly have had for centuries,” Tremblay said. “One of the things about astrophysics and observational astronomy is that we are in a unique position in which to try to seek an answer to this question, and that's something that I've been working on. My challenge is to try to understand and decide if there is a prevalence of intelligent beings somewhere within the universe, and that's a significant challenge that requires astronomy, physics, mathematics, engineering, computer engineering and a number of other skills.”

Tremblay discussed the connections between mathematics, physics and astronomy in modern science. She said her job would not be possible without math. She gave a bit of history to show the intertwined relationship between astronomy and mathematics. She said Henrietta Swan Leavitt discovered the correlation between Period and Luminosity, which is an astronomical relationship that allows us to measure distances. Without that discovery, Edwin Hubble would not have discovered that galaxies existed.

“Without this mathematics, that revelation would have never happened,” Tremblay said. “We really needed mathematics in order to do astronomy and to build it.”

She said to get a more expansive image of the sky, one can build a very large telescope or utilize arrays of them.

“When we do that we use mathematics to combine these, [which] simulates a single antenna,” Tremblay said. “

With SETI, Tremblay spends half of her time working as a project scientist, also known as a project manager, for the Commensal Open-Source Multimode Interferometer Cluster on the Karl G. Jansky Very Large Array, which is designed to search the entire sky for extraterrestrial intelligence. She said there are two analogous but separate fields in the search for extra terrestrial intelligence: biosignatures, and technosignatures. Biosignatures are discoveries related to things happening within the atmosphere of planets for certain molecular structures that either “signify that somebody is modifying their environment” or the presence of bacteria. Technosignatures are what Tremblay searches for and are electronic signals that suggest communication or technology building.

“Technically, anybody can be communicating across any wavelength across the electromagnetic spectrum. But what happens is that as soon as you get into an atmosphere, it's really hard to project certain wavelengths,” Tremblay said, adding that larger wavelengths are less likely to be impeded by travel through an atmosphere and across the vast distances in space. “Radio waves is thought to be the best way to go about doing this search, at least in the beginning. … So their suggestion is that we look at radio waves. And also we can build radio technology relatively cheaply, so maybe somebody else can as well.”

Tremblay added that this can be limiting in that it likely wouldn’t account for a very long period in the development of a civilization, because we only started using radio waves to communicate in World War I.

Tremblay said that astronomers have a lot of control over sensitivity, frequency and distance in bandwidth of the signals being searched for. The only issue is the vastness of space.

“Across our own galaxy only, we've only searched two times ten to the minus 16th of the galaxy [which according to the Tiger Algebra website is 0.0000000000000002],” Tremblay said. “So where are all the aliens? We don't know, but we haven't searched enough to actually answer this question.”

Tremblay said in the past decade, SETI has received private funding and has collaborated with other entities to operate twelve telescopes around the world – a number that continues to grow. The search for extraterrestrial life continues.