Earlier this month the journal Nature published an article written by myself, Debra Fischer, and Victoria Meadows. This commentary piece sketches out the case for a deep revision of how the study of exoplanets and the quest for life elsewhere is both conceptualized and implemented globally.
The idea, in a nutshell, is that exoplanetary science has more or less exploded out of nowhere in the past couple of decades and hasn't yet found its optimal slot within an array of related scientific disciplines and communities. In fact, we argue that part of the problem is that there are so many disciplines and fields where exoplanetary science is relevant, and where it also needs to draw on accumulated knowledge, that the real place for it is at the center of a systems science web.
That's a viewpoint almost guaranteed to annoy someone. But I think expressing it is the only way to make sure we don't miss out something critical in how we pursue some very big questions.
Systems science is about understanding interactions between phenomena, and is a sophisticated extension to more traditional approaches to questions. For example, in the past we might expend all of our scientific efforts on isolating and 'cleanly' examining a property or behavior - from things like electrons to human brains. This is a critical way that we learn about the natural world. Removing noise and extraneous correlations from a phenomenon can help you pin down root causes and mechanisms. It's a wonderfully rational and powerful strategy.
Except those fundamental properties may never actually be so isolated in nature. The result is that we can sometimes struggle to understand how natural systems are working even if we know how all the components function in special, laboratory conditions. To push further along we need to both step back and get deeper into the weeds.
Parallels exist with the phenomenon of emergence. For example, we might understand the behavior of a single water molecule very well. But the behavior of fluids or snowflakes would neither be an obvious consequence or a tractable problem without higher-level appreciation of the properties and relationships of much more complex systems where quadrillions of water molecules are interacting. You'll learn more about fluid dynamics pouring a glass of water than you will by studying the properties of hydrogen and oxygen.
Exoplanetary science is also a lot like Earth science, where systems approaches are very familiar. To begin to understand how our planet functions you need to understand how all the pieces fit together, from atmosphere to oceans, chemistry to geophysics. But today we have the field of 'Earth science' in part because this world has long been the only planet we could study in sufficient detail to be interesting. If the last few centuries had included similar access to other planets in the solar system, or further afield, the science would have developed very differently.
The data we currently have on exoplanets is obviously rudimentary in the extreme. Ask an astronomer about a newly discovered world and they'll say something like: there's a planet, it's more or less this diameter, it's more or less this mass, it perhaps has an atmosphere, and this is the kind of star it orbits. The information content doesn't begin to match the richness of Earth science.
But there's a key difference. For this one crudely characterized world there are millions (probably billions) of other rocky worlds waiting to be unlocked with our telescopes. In a very real sense, what we lack in detail for now, we make up for with sheer number. Building big data on exoplanets, hand-in-hand with intense studies of a few luckily-suited worlds, should let us construct a hybrid approach - overlapping with, and extending traditional areas like Earth science and planetary science of the solar system.
To manage that we actually have to start doing proper exoplanetary science right now. In other words, it's time to move to a bold vision of exoplanetary science that is really exoplanetary systems science. It would be the generalization of other systems science approaches to planets, and eventually to life's origins and cosmic nature.
Finding other life, and learning about where and how it starts looks like an even bigger challenge than figuring out planets. Except it's really where we want to go, it's the aim point for all this research in my opinion. And we're increasingly recognizing that life on Earth is no more separate from the planet than a car is from its engine. Life is an expression of the deep physics and history of a world; a piece of energy dissipation, a participant in the great planetary circuits of electron flow and chemistry - an emergent force of mind-boggling complexity. To figure all of that out we must at least get the exoplanetary piece in shape.
Doing this won't be entirely straightforward. In our Nature paper we argue for a reworking of funding structures, and for professional scientific societies and organizations to start gathering people to hash out the details. We'll see if anyone heeds this call.