For generations, man has gazed into the starry night sky scanning the stars and constellations, pondering the thought of whether we are alone in this vast universe and for the most part, believing that we on Earth are not alone. Finding intelligence or simple life forms is an imperative question to answer. Our views on our existence would inevitably shift knowing that we are not alone, not unique and actually part of a much bigger society. According to NASA there are approximately 8.8 billion habitable planets like Earth, orbiting a sun-like star in a goldilocks zone in our Milky Way alone. Since the 1960s SETI have searched for signals from intelligent life and digital information has been transmitted into space for alien explorers to discover. Unfortunately we have only been met with deafening silence. Is it possible to be the only intelligent life form in the entire galaxy?
Recently, NASA announced its discovery of liquid water flowing down steep relatively warm Martian surfaces. Using imaging spectrometers, researchers detected signatures of hydrated minerals on these slopes where the streaks were seen on the red planet. The first piece of evidence for water on Mars was found in 2000, where gullies discovered were suggested to have a liquid origin, but this has been debated for many years. NASA observations have indicated that rivers and oceans were prominent features in its early life. Billions of years ago Mars had been thought to have appropriate conditions for microbes to develop due to the amount of water present. However, as Mars is relatively small and with a weaker gravitational pull relative to Earth, it has been suggested that over time the liquid water had evaporated and escaped the atmosphere, leaving less water on the Mars surface and a less suitable condition for life to evolve.
Intelligent life forms do not spontaneously appear (apologies to creationists), but instead evolve over billions of years. The approximate age of the universe is 13 billion years and Earth formed roughly 4.6 billion years ago. After 500 million years, the Earth’s atmosphere begun to stabilise and slowly cool down to a suitable condition for life to exist. Fossil evidence suggests that life on Earth existed approximately 3.5 billion years ago, undergoing five mass extinctions caused by various factors such as sudden methane release and volcanic eruptions. The most famous mass extinction took place 65 million years ago, in which a 10km wide comet or asteroid smashed into the Earths rocky surface releasing energy equivalent to a billion nuclear bombs and wiping the dominant species, the dinosaurs. Steve Brusatte, a palaeontologist at Edinburgh University says that “if it wasn’t for that asteroid, then humans probably wouldn’t be here. It’s as simple as that”. We are indeed extremely fortunate that we exist, that organisms on Earth have survived five mass extinctions due to catastrophic natural hazards and continued to evolve over the years into intelligent life forms. This success story seems highly unlikely to occur regularly throughout space. If intelligence was common throughout the galaxy, we would probably find more evidence, for example on Mars, but it seems that intelligent existence is a scarce phenomenon.
The presence of intelligent life may be improbable, but it is not impossible and our existence is proof of that. Earthlings survived against the odds and a similar journey could have taken place elsewhere in the universe, we just haven’t discovered it yet. There could be an extra-terrestrial intelligence thousands of light years away pondering the same questions, asking itself, are we alone? But in this moment in time, as incredible as telescopes may be, they are not advanced enough to explore distant star systems in detail and find intelligence. Astronomers have broadcasted radio signals radially outwards for nearly 100 years, but the furthest distance it has reached due to attenuation is 70 light years, which is microscopic compared to our 100,000 light year wide galaxy. To quote Neil deGrasse Tyson “Life doesn’t exist anywhere but earth? That’s like filling a cup with ocean water and saying there aren’t any whales”. It would be greatly ignorant to suggest that we are alone in this universe based on the lack of evidence, we are only just getting started.
In January 2016, our search for intelligence continues as Yuri Milner funds the most extensive search for life yet, the Breakthrough initiatives project. This study will allow astronomers to eavesdrop on planets that orbit millions of the closest stars to Earth and up to a hundred nearby galaxies. The radio surveys will cover ten times more of the night sky than previous programmes and cover five times more of the radio spectrum. This project is backed by SETI founder Francis Drake and cosmologist Stephen Hawking amongst other profound astronomers. Hawking says “It’s time to commit to finding the answer, to search for life beyond Earth”. Breakthrough initiatives will not broadcast signals into space because the scientists on the project believe there is more to gain from listening than transmitting signals into the cosmos.
Although there has been a lack of success in our search for intelligent species, we have been successful in other areas. From looking far into the distance we have expanded our knowledge on various aspects of astronomy; from star systems to habitable planets and technological limits. However, the motivation to find alien life is not like any other research project, if successful, it would change the entire world’s perspective on life in similar ways as Darwin’s work did. The answer does not only apply to the astronomers studying the cosmos, the search for intelligence affects us all. In my own experience, my interest in physics was sparked by the idea of discovering alien life, I continued to read and watch documentaries related to astronomy and physics and as a result, I sit here writing an article near the end of my degree on the very same idea which ignited my interest physics. This is why I believe promoting projects like Breakthrough or SETI are extremely important, it is a captivating area of science which will not only continue to progress but also grasp the attention of younger generations, inspire and provoke thought amongst millions.
The presence of intelligence signifies a tremendous several billion year journey of evolution and survival. The existence of humans is down to the survival of very few life forms surviving mass extinctions and fundamentally the extinction of the dinosaurs. In my view, the reality of human existence, based on scientific evidence alone tells me that we are extremely lucky, through billions of years of life and death, eventually Earth became host to intelligent life.
Unfortunately, our search for alien life has been unsuccessful so far, but worth it. The search for intelligence is a motive to sweep the night sky, study and learn more about the cosmos, but not only will it benefit scientists, it will continue to inspire younger generations and bring the public closer to science. In an era where we are less dependent on religion and ancient myths, the search for intelligence can provide the answers we as a race have been looking for, it will shift the world’s perspective on the universe and ourselves, whether we are alone or not.