What in the World is Astrobiology and What Does Johnny Durkin Have to Do With It?

Astrobiology is more than a field of study; it’s a multidisciplinary exploration of some of the most profound questions humanity has ever asked.

What is life?

How did it originate?

Are we alone in the universe?

These are not questions with simple answers, and that’s precisely what makes the field so exhilarating.

For me, the journey into astrobiology began when I transferred into the School of Earth and Space Exploration at Arizona State University. This program opened the door to an interdisciplinary curriculum that included biology, chemistry, physics, geology, geochemistry, astronomy, and engineering. Each discipline contributes a piece to the grand puzzle of life’s mysteries, making astrobiology an intricate tapestry of scientific inquiry.

What Is Life?



The question, “What is life?” seems simple at first glance, but its complexity becomes apparent the moment we try to define it. Life surrounds us in countless forms, from the tiniest microbes to towering trees and intelligent humans. Yet when we dig deeper into the essence of what makes something “alive,” the lines blur. Is life merely a set of chemical processes, or does it encompass something more profound? This question is not just philosophical—it lies at the heart of astrobiology.

Defining Life: The Traditional Approach

Traditionally, life is defined by a set of characteristics that distinguish living organisms from non-living matter. These include:

Homeostasis: The ability to maintain internal stability, such as temperature or pH balance.

Metabolism: The conversion of energy and matter into usable forms.

Growth: The capacity to increase in size or complexity over time.

Reproduction: The ability to create offspring or replicate.

Response to Stimuli: The capacity to react to changes in the environment.

Evolution: The ability to adapt and change over generations.

While these criteria work well for organisms on Earth, they may not encompass all possible forms of life. For example, viruses lack metabolism and cannot reproduce independently, yet they evolve and interact with their environment.

Are viruses alive? The answer depends on who you ask.

One of the most captivating aspects of astrobiology is how we define life—and the truth is, we don’t have a universally accepted definition.

Consider a thunderstorm. It grows, expends energy, interacts with its environment, and eventually "dies," yet we don’t classify it as alive. Why? This philosophical and scientific gray area is where the research of astrobiology thrives. Life, as we understand it, is both a biological reality and a conceptual framework we’re still refining. We don’t know exactly what it is or where it began or even where it came from.


The origin of life is one of science’s greatest unanswered questions.

How did non-living chemicals transition into the first living organisms?

Theories abound, but no definitive explanation has emerged, making the origin of life an area of vibrant scientific inquiry. One possibility is that life began here on Earth through a gradual chemical evolution. Simple organic molecules, under the right conditions, could have combined into more complex compounds, eventually forming self-replicating structures like RNA. This scenario likely involved environments rich in energy sources—such as hydrothermal vents, volcanic pools, or even lightning strikes. Experiments like the Miller-Urey experiment in the 1950s demonstrated that amino acids, the building blocks of life, could form under simulated early Earth conditions. These findings offer tantalizing clues but leave the bigger picture incomplete.

Another compelling hypothesis is panspermia, which suggests that life, or at least its building blocks, didn’t originate on Earth but arrived from elsewhere in the cosmos. Meteorites containing amino acids and other organic compounds have been found on Earth, showing that the ingredients for life are widespread in the universe. Could a meteorite have delivered these molecules to our young planet, setting the stage for life to emerge? Alternatively, life itself might have originated on another world or even within the dense molecular clouds of interstellar space. Recent discoveries of complex organic molecules in space, such as glycine in comets, support the idea that the building blocks of life are not unique to Earth. If panspermia is correct, life on Earth could be part of a larger cosmic story—a single thread in a vast interstellar tapestry.

Still, the possibility remains that life originated entirely on Earth but under circumstances we have yet to fully comprehend. Hydrothermal vents on the ocean floor provide a particularly intriguing setting. These vents release mineral-rich water heated by geothermal energy, creating environments with steep chemical gradients—ideal conditions for the synthesis of organic molecules. Another possibility is volcanic pools, where cycles of drying and wetting could have concentrated organic molecules and facilitated their combination into polymers like RNA. Even more speculative is the idea that lightning strikes in Earth's primordial atmosphere played a role, as shown by the Miller-Urey experiment. These varied hypotheses reflect the incredible diversity of environments where life might arise, emphasizing the adaptability and potential universality of life’s chemical roots. Whether the spark of life came from Earth’s own chemistry or from the cosmos beyond, understanding its origins will deepen our understanding of biology, chemistry, and the history of our universe.



Ultimately, the origin of life remains an enigma.

How Do We Search for Life?

The search for extraterrestrial life takes many forms. The Search for Extraterrestrial Intelligence (SETI) uses radio telescopes to scan the cosmos for signals from intelligent civilizations. Closer to home, missions like the Europa Clipper and the upcoming Enceladus probe aim to investigate the subsurface oceans of icy moons in our solar system, while Mars sample return missions seek signs of ancient microbial life on the Red Planet.

Even here on Earth, researchers are exploring the concept of “weird life”—organisms with fundamentally different biochemistries, potentially challenging our assumptions about what life can be. These efforts collectively expand the boundaries of our understanding. So this is where I too focused my efforts.

My Take: Aliens Are Out There and Here's What They'll Look Like

My own astrobiology journey led me to focus on extremophiles: microorganisms that thrive in the harshest environments. Space is cold, and water is often ice. What could live at the interface of ice and liquid water? What simple life forms can survive with minimal energy inputs? These questions drove my undergraduate research as part of a NASA Space Grant project.

I studied Arctic sea ice algae as analogues for extraterrestrial life. These diatoms not only endure extreme cold but also reproduce using light energy and limited nutrients. They embody the resilience we might expect from alien microbes. Excitingly, biosignatures produced by similar Arctic diatoms—specifically dimethyl sulfide (DMS)—have been detected on the exoplanet K2-18b. Could this be evidence of extraterrestrial life? Only time, and more research, will tell.

Why Astrobiology Matters

Astrobiology’s beauty lies in its ability to unite fields of science to address universal questions. It’s a discipline that requires creativity, collaboration, and an openness to challenge our assumptions. My journey so far has taught me that the search for life isn’t just about finding aliens; it’s about understanding ourselves, our origins, and our place in the cosmos.

This blog marks the beginning of writings where I’ll delve deeper into these topics, sharing insights, resources, and ideas that have shaped my perspective.