We detected the first exoplanet in 1995. Since then, the existence of more than 4,000 others has been confirmed, and considerable effort is now going into determining whether any of them can support life. Other researchers are looking closer to home as well, probing Mars and, more recently, Venus for signs of ancient or extant extraterrestrial organisms.
This search for life beyond our planet raises fundamental questions about our place in the universe and what exactly it means to be alive. Finding the answers requires us to tackle three interlocking challenges: understanding the matter from which life is made; understanding how life first came into existence, finally understanding life’s most complex configuration — consciousness.
If we can make progress here, it will do more than answer the question of whether we are alone in the cosmos. It will also transform our understanding of ourselves and our planet. Such self-knowledge could greatly increase our capacity to shape the world we live in, and will be crucial for charting the future of life on Earth and further afield.
We have already come a long way on the first of these challenges. While many mysteries remain, the fields of molecular biology and organic chemistry have given us unprecedented insight into how matter supports the functions of life, and creates the inner workings of the cells all organisms are built from.
But while this knowledge has dramatically improved our ability to read and write in the language of life, we still have few ideas about how it started from first principles. At some point in the distant past, simple chemical reactions quite literally took on a life of their own, but how and why remains unclear.
We do know some of the key ingredients. The first organisms must have had a protective barrier to separate chemical reactions integral to their existence from those occurring in the wider environment. The right chemistry also needed to be encapsulated inside this barrier to ensure the organism could thrive and proliferate. This must have included catalytic elements that can harness energy from the environment to power the reactions necessary to sustain a living entity. A system for encoding and replicating the instructions for this internal chemistry would also have been crucial.
We understand how today’s cells solve these problems, using processes like the Krebs cycle to release energy stored in nutrients and catalytic processes to make components to sustain life with DNA and RNA controlling the duplication mechanism. But modern organisms are the product of millions of years of evolution and the chemistry of early life on Earth must have been much simpler. The challenge facing us is something like having to reverse engineer the Wright brother’s first airplane using only the schematics for the Space Shuttle.
This is where the hunt for life on other planets could serve us well. While we can dream of finding life on Mars, the prospect of discovering some early chemistry that predates the first cell and sheds light on the journey towards life’s existence is just as exciting.
As we take our search beyond our solar system, we will also be forced to confront more foundational questions. For instance: is there a specific set of conditions and chemical precursors that creates an optimal pathway for achieving life? Or are the organisms found on Earth just one of life’s many possible configurations and could it also arise out of entirely different chemistries and utterly alien environments?
While we have a long way to go in solving these riddles, our growing command of the foundational matter of life and our increasing ability to probe other worlds is putting them within reach. Such a fundamental understanding of the origins of life could have profound implications for medicine and could even open up the possibility of building new life from scratch.
The prospect of such God-like abilities is both exciting and frightening, and makes the final question concerning consciousness all the more important.
Modern society is built on thousands of years of accumulated knowledge and scientific discovery, but humans remain a product of their evolution and are driven as much by ancient animal urges as by rationality. Understanding how this tension governs our behaviour and how our consciousness is tied to our biology will be crucial to predicting where this knowledge will take us.
Here the challenge seems much more daunting. Our understanding of the human brain is still rudimentary and, despite the name, artificial intelligence is a long way from helping us recreate true intelligence — let alone consciousness. It is not even clear whether we have a brain that is capable of truly understanding itself. Much like our inability to grasp what came before the Big Bang, consciousness may be a mystery we can never solve.
However, that doesn’t mean we shouldn’t try. Efforts to deconstruct and reverse-engineer the brain will be critical, but we should also make use of the powerful and largely unused tool of social media. The data collected by these services could help us unravel the psychology of an entire species and we should ensure it is accessible to scientists seeking to make sense of consciousness.
Across all three of these challenges, there is also a need to think about life differently. Rather than taking the traditional biological approach of simply trying to understand the function, we need to approach these problems more like mathematicians or physicists and deconstruct them in order to capture their essence.