We often ask what is life and how is it defined? It is a query that intersects with both scientific inquiry and philosophical contemplation. Dr. Sara Imari Walker poignantly noted in one of her books how scientists, in a number of conferences, would start off by saying that life is hard to define but would then go on to try to define it.
All life that we know on Earth is carbon-based and it stores its genetic information as deoxyribonucleic acid, DNA and uses proteins to carry out functions like metabolism, motility and others. Regardless of how we analyze it, the fundamental truth remains: we can only observe and understand what information is contained within life whereas, how that information got assembled will perhaps always be an enduring mystery.
The absence of definitive evidence of extraterrestrial life challenges our understanding in the quest of astrobiology, whose central goal is to find evidence of past or present life beyond Earth, if at all it exists/existed.
Since at present, there is no life beyond Earth detected and no evidence of past alien life has been found, does it mean that we are alone or that the universe is lifeless? The difficulty in answering this question parallels the challenge that Leonardo da Vinci faced five centuries ago when he grappled with what “water” is. Today, with the help of molecular theory, it is easy to define water as H2O because regardless of its state- liquid, solid or vapour, water stays as H2O. However, no such clear consensus or definition exists for understanding what life is.
It is possible-though no such evidence exists- for different forms of life to exist on Earth or elsewhere in the solar system and beyond but remain undetected. It may be a form of life that is unlike the DNA-protein life that we know.
Scientists have devised many ways to look for life elsewhere such as in situ investigation of the solar system, where a spacecraft lands on celestial bodies and conducts experiments at the surface. Biological examination is another way in which samples from such bodies are brought back to Earth either in a controlled manner (as samples brought back by a dedicated spacecraft) or uncontrolled manner (as meteorite debris due to a big impact). The light coming from the atmospheres of other worlds is also used to determine the chemical composition of their atmospheres with the hope of finding chemical signatures of another biosphere. Besides looking for life elsewhere, the search for intelligent beings in other star systems is also carried out under what are popularly known as SETI experiments.
All this would perhaps naturally lead to a broader question: how does knowing whether life exists elsewhere in the universe matter at all to us on Earth? Our limited understanding of life’s fundamental characteristics itself tells us that we may not even be taking the right approach towards the search for life or the story of life elsewhere.
Experts offer many reasons why somebody or something might be out there, yet still beyond our detection. The ultra-cautious, on the other hand might remind us that, while a lifeless cosmos seems unlikely, we have zero information one way or the other.
From a Christian perspective, we are not alone. The Bible provides a foundation for understanding God’s creation and explicitly declares that He has indeed created extraterrestrial beings called angels that are not constrained by the universe’s laws of physics or the universe’s space-time dimensions. Genesis 1:26-28 suggests the creation of life, in human form as a focus on Earth only. What may be open for debate is whether there are living beings, of human form elsewhere in the universe too. From a scientific perspective, we are trained to keep looking.
Thus, as we search for the truth that lends meaning to our endeavours, it becomes clear that discovering whether life exists or not elsewhere in the universe holds profound significance. Such a discovery would not only deepen our understanding of life’s nature but also reveal something fundamental about the relationship between science and faith. After all, what is the value of scientific exploration if it offers no insight into our place in the cosmos?
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