This article was first published by The Conversation. Space.com's Expert voices: Op-Ed and Insights was contributed by the publication.Predrag Slojepcevic is a Senior Lecturer in Biology at Brunel University LondonNalin Chandra Wickramasinghe is an Honorary Professor at the University of BuckinghamIs the universe our only source of information? Since 1959, the SETI (Search for Extraterrestrial Intelligence), program has attempted to answer this question. American Astronomer Carl Sagan and others believed there must be other human-like civilisations and that we could communicate. Skeptics, however, aren't convinced. They argue that there is no evidence to support such civilizations and they are extremely rare.If other human-like civilisations don't exist, are there other forms of life that might be better suited to spreading in the cosmos than ours? Would it be possible for these lifeforms (non-human SETI), to communicate with one another? The results of our new study, published in Biosystems. The cosmic rulers may be microbes like bacteria. They are far more intelligent than we think. We show how microbes can mimic the SETI program with no human intervention.We must challenge our anthropocentric preconceptions in order to understand microbes. Many people think that microbes are single-cell organisms that cause disease. But the truth is quite different. Microbes are multi-cellular, loosely organized entities. Bacteria is one example. It lives in member colonies of many billions of colonies that are capable of "thinking" as well as decision-making.A typical bacterial colony looks like a cybernetic entity, a "superbrain", that solves environmental problems. Importantly, all bacterial colonies are connected to a global supersystem of bacteria called the bacteriosphere. Over the last three billion years, this "world-wide web" of genetic information has controlled the flow of organic materials on Earth in a way that will never be surpassed by human capabilities. They also cycle essential nutrients like carbon, nitrogen, and sulfur.Bacteria is the dominant living organism on Earth today. Life will slowly end if bacteria is removed from the biosphere. Bacteria might be better suited to cosmic travel and communication than we are. Recent research has shown that terrestrial bacteria can survive in space for at most three years. It is possible to live longer. It is clear that microbes can survive in space for at least three years.Many versions of the panspermia hypothesis, which asserts that microbial life exists and can travel throughout the universe, support this idea. Recent mathematical models support this idea by showing that microbial travelers may be possible in the solar system as well as throughout the galaxy.Microbial SETIHow would microbial SETI function? The bacteriosphere may be able to replicate the human SETI steps. The ability to understand cosmic-scale information is step one of human SETI. Radio telescopes can be used to analyze distant planets that might have potential for life. The second step is to create technologies and knowledge that can be used to determine if there are any habitable planets. The third step is to announce our presence on Earth and try to contact intelligent extraterrestrials if they respond.The picture below shows our version of microbial SETI. The cosmic-scale information is only available to microbes with a limited ability. Cyanobacteria, for example, can detect the visible portion of electromagnetic spectrum from the sun (step one). Phototropism is a biological phenomenon that occurs when plants turn towards or against the sun or another light source.(Image credit: microbial seti)The second step was critical to the development and maintenance of life on Earth. Cyanobacteria created a biotechnology called photosynthesis, which converts water, sunlight and carbon dioxide into oxygen, and nutrients. Over a long evolutionary process, this transformed the dead planet into the living one known as the bacteriosphere. The complexity of microbes then led to the creation of plants and animals over 600 million years. Despite this, bacteria is still the dominant form of life on the planet. Photosynthesis is a form bacterial technology that has fuelled life on Earth for centuries.Step three is about communication and attraction between microbes that have similar chemistries. If they have similar chemistry and metabolisms, extraterrestrial microbes will be able integrate seamlessly into Earth's bacteriosphere. It is also possible to do the opposite. The possibility exists that microbes from Earth could travel to space via asteroids, and then seed life in other parts of the cosmos. Humans could also act as microbial vectors through their microbiomes as future cosmic travelers.Understanding the evolution of intelligence is essential to appreciate microbial SETI. This will allow us to better understand the capabilities of bacterial intelligence and how they relate to human and microbial SETI. Some biologists believe that intelligence in humans is only a small part of a vast array of natural intelligence, which includes plants and microbes.It is also important to reconsider technological signs as indicators of intelligent civilizations. According to Freeman Dyson, technologically advanced civilizations must have high energy requirements. This could be achieved by creating cosmic megastructures (dubbed Dysonspheres) around the planets. These structures can capture energy from their host star. Such spheres can be found by checking whether the light from stars has been blocked.However, it is not worth searching for human-like civilisations if they are rare. It may be better to look for biosignatures that could indicate microbial life on planets.One way to find extraterrestrial life is to search for gases in the atmospheres of planets. These gases are all made by microbes. Although the discovery of phosphine within Venus' atmosphere was promising, a new study suggests that it could have been sulfur dioxide. We cannot help but keep trying. The James Webb Space Telescope, which will launch later in the year, should be capable of scanning the atmospheres of planets orbiting stars other that our Sun.This article was republished by The Conversation under Creative Commons. You can read the original article.Follow Expert Voices to keep up with the debates and issues. You can also join the conversation on Facebook and Twitter. These views are the author's and may not reflect those of the publisher.
