When I talk about what I do, I usually like to give the general definition of astrobiology as "the study of the origins, evolution, and radiation of life in our universe".
However, when I personally think about what astrobiology means to me, I think I can just as easily say that "astrobiology is the human pursuit to understand life". Astrobiology is more than just the science of studying past and present life on Earth and looking for life elsewhere. To me, the most important aspects of astrobiology lie in the philosophical realm. Astrobiology takes the power of science and applies it to the oldest questions we humans have asked about why and how we came to be, without needing to fall back on mysticism or the supernatural.
For me it means organics and water, as we factually know that life can spawn from carbon compounds and the ph neutral amphoteric chemical. Any other medium that might lead to life is still only theory. We now know that organics and water are part and parcel products of stellar evolution. See video
Organics and Water in Space: The Spectroscopic Legacy of the Herschel Space Observatory https://astrobiology.nasa.gov/seminars/featured-seminar-channels/na...
The definition of astrobiology always strikes me when I start marveling about the trillion-trillion circumstances that gave rise, in a dynamic way, to all life on our planet...I think you can't really talk about defining astrobiology in any sense unless you include some aspect of the human condition about uniqueness, obscurity, chance/fate and expectations. Perhaps this is just some kind of arrogance, but I believe that astrobiology touches on these kinds of philosophical aspects, at least more so than some other fields (including my own field of focus, geology!).
Thanks folks! I see astrobiology as an integrated science framework, which allows scientists such as microbiologists, geologists, astronomers, etc, to understand each other and work on common problems. I do appreciate the philosophical aspects of astrobiology like Graham and Zach pointed out, a great deal, which is why I love the field so much. I think it just raises one's awareness of a cosmic context, and increases one's sensibility to how interconnected the Earth as a system is with its biology, but also with its space environment. That in itself is very healthy from a scientific perspective, as it is easy to get bogged down into details.
I usually use the textbook definition of astrobiology as "the study of the origin, evolution, distribution, and future of life in the universe". But I'm going to go a little philosophical on this one for the discussion here. One of my favorite ways of thinking about cosmology and why it is such an important discipline is really "we are how the universe thinks about itself" (not sure where that idea originates, does anyone know? I've seen it a few places). For astrobiology we could go one further with "astrobiology is how the universe thinks about how it can think about itself". Gulp! So astrobiology is clearly pretty important to understanding our place in the cosmos, which makes it all the more exciting!
The study of anything that relates to the bigger picture of Life in the Universe. :)
I have always appreciated the science of astrobiology for how amazingly it combines the two disparate scientific streams – Astronomy and Biology, in general, and proposes the whole concept of biological universe. I feel an innate proximity with this science as I can relate my own radical questions about life, and creation as whole, to it. So, I personally see astrobiology as sheer “Natural Philosophy”, which seeks to understand the ultimate puzzle of provenance through natural laws. As Carl once said that “somewhere, something incredible is waiting to be known”, astrobiology leads the search of that “unknown” on the basis of known scientific rationales. I think astrobiology endows us with a vast cosmic perspective, that we are so intimately connected with the cosmos and arose from the universal physical principles. Another inherent feature of astrobiology, which is most appealing to me personally, is that astrobiology is really a “science of optimism”, which believes that life exists elsewhere in the universe and can be detected; which never gives up on the pursuit of exploration despite uncertainties.
A beautiful expression that I’d like to cite here:
We shall not cease from exploration And the end of all our exploring Will be to arrive where we started And know the place first time
- T.S. Elliot