When thinking and talking about “astrobiology,” many people are inclined to think of alien creatures that often look rather like us, but with some kind of switcheroo. Life, in this view, means something rather like us that just happens to live on another planet and perhaps uses different techniques to stay alive.
But as defined by NASA, and what “astrobiology” is in real scientific terms, is the search for life beyond Earth and the exploration of how life began here. They may seem like very different subjects but are actually joined at the hip; having a deeper understanding of how life originated on Earth is surely one of the most important set of clues to how to find it elsewhere.
Those con-joined scientific disciplines — the search for extraterrestrial life and the extraordinarily difficult task of analyzing how it started here — together raise another most complex challenge.
Precisely how far back do we look when trying to understand the origins of life? Do we look to Darwin’s “warm little pond?” To the Miller-Urey experiment’s conclusion that organic building blocks of life can be formed by sparking some common gases and water with electricity? To an understanding the nature and evolution of our atmosphere?
The answer is “yes” to all, as well as to scores of additional essential dynamics of our galaxies. Because to begin to answer those three questions, we also have to know how planets form, the chemical make-up of the cosmos, how different suns effect different exoplanets and so much more.
This is why I was so interested in reading about a breakthrough approach to understanding the shape and nature of interstellar clouds. Because it is when those clouds of gas and dust collapse under their own gravitational attraction that stars are formed — and, of course, none of the above questions have meaning without preexisting stars.
In theory, the scope of astrobiology could go back further than star-formation, but I take my lead from Mary Voytek, chief scientist for astrobiology at NASA. The logic of star formation is part of astrobiology, she says, but the innumerable cosmological developments going back to the Big Bang are not.
So by understanding something new about interstellar clouds — in this case determining the 3D structure of such a “cloud” — we are learning about some of the very earliest questions of astrobiology, the process that led over the eons to us and most likely life of some sort on the billions of exoplanets we now know are out there.… Read more