• What is Astrobiology?

    Given our recent (and completely unanticipated) bump in traffic, I think now would be as good a time to introduce people to astrobiology, the field to which I have devoted my professional life, and the subject of many of the discussions here at PaleBlue.blog. Let’s start by answering a question that has caused some confusion as of late:

    What is Astrobiology?

    The closest thing I’ve seen to a universally-accepted definition of astrobiology is the one also found on Wikipedia:

    Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe.

    A Brief History of “Probably Nothing… So Far”

    When one lives and works in the DC area (like I do), one is often asked “What do you do for a living?” When I answer this question (“I look for ways to look for aliens”), I am often asked the same follow-up question: “Have you found anything yet?” The best short answer I can to give to this question is: “Probably not… but it’s complicated.” You see, most astrobiologists make the assessment that there has been no convincing evidence that we have detected life on another planet. However, a few claim that the Viking Lander discovered life on the surface of Mars, or that there is evidence for fossilized life in the “Alan Hills meteorite.” Both these claims have their merits, but both also have very serious problems. Because scientists are a conservative bunch, and because “I found aliens!” is quite the stunning conclusion, the astrobiology community remains unconvinced based on the balance of evidence presented thus far. That said, the options for life beyond Earth are far from exhausted… and so the search continues.

    A Field Without Any Data

    One common critique of astrobiology is that given the above conclusions (that there aren’t any known aliens), ”Astrobiology is a scientific endeavor without a single data point.” Such critiques miss the point… in more ways than one. First of all, look at the definition above. Astrobiology is not “the study of aliens.” It’s the study of life in the universe. That includes this. And this. And… this. And lest you think that all of that only encompasses “one data point” I suggest you take a look at this.

    OK, but what do Astrobiologists DO? And how is that different than biology?

    Given that there has not been a positive detection of life to-date, much work in astrobiology focuses on the possibilities for life beyond Earth. To do that, we try to tackle fascinating questions that yield complex answers: How can we look for life? Where are the best places to look for life elsewhere? What are the limits of the life we know of?  What common properties does all Earth life share? Would alien life also have to share these properties? How has life affected the planet Earth through time? How have changes to the Earth affected the evolution of life? How did life start on Earth? Astrobiologists research these questions with a wide variety of tools: chemistry, biology, physics, planetary science, geology, astronomy, and anthropology. You can’t answer these questions on biology alone. Sure, sometimes these tools are used by astrobiologists in isolation to make tremendous advances in both astrobiology and in their own disciplines. But many times, these questions require us to leverage these tools off each other to make exciting new discoveries that would not be possible without a dedication to collaboration. Astrobiology is more than biology: it’s biology in a planetary and astrophysical context, studied on geological timescales and extrapolated to the limits posed by physics and chemistry.

    So… it’s complicated… but that’s what astrobiology is, and that’s what we do.

    More broadly, we are scientists, and do the things that scientists do. We work late into the night within labs, on computers, at observatories, in the field, and throughout the oceans. We do this to rigorously pursue answers to questions we have been collectively asking for as long as we’ve had the capability to collectively ask questions. We don’t have the answers to all of them yet, but we’re working on it. And rest assured, when we do have the answers, we’ll be sure to let you know. Stay tuned…