In Conversation: Voices on “On Water” — Prof. Dr. Ulrike Ernst-Auga

Water Worlds and Outer Space

In the search for extraterrestrial life, water is considered a key element. Why do we so readily associate water with life—and what does that reveal about our own understanding of life?

So far, we know only life on Earth—and all known life depends on water. That is why we also search for liquid water and possible traces of past water on other celestial bodies. Yet this reveals a fundamental epistemological limitation: we are searching for unknown forms of life using criteria derived from our experience of life on Earth. The search in space therefore brings us back to a more fundamental question: not only “Where is there life?” but first of all, “What is life—and how would we recognize it if it were entirely different from what we expect?”

Mars, too, once had large quantities of liquid water; today, what remains is mainly ice and traces of former bodies of water. Does this story of water in space ultimately also tell us something about the fragility of water systems on Earth?

Yes. Mars is a striking reminder that the conditions on a planet are not immutable. Where dry landscapes extend today, we find traces of a past in which liquid water shaped the surface. Looking at Mars therefore also means looking back at Earth: water is not a self-evident and infinitely available resource, but part of delicate planetary systems. The search for water in space can therefore help us recognize anew just how precious and vulnerable the conditions are that make life on Earth possible.

Decolonizing Astrobiology

Your research brings postcolonial perspectives into dialogue with space research, among other fields. What does it mean in concrete terms to decolonize astrobiology?

To decolonize astrobiology means critically examining which ideas of discovery, ownership, expansion, and progress we carry from Earth into space. Who gets to imagine cosmic futures, whose knowledge counts, and who decides what is worth protecting? The Moon, Mars, and possible extraterrestrial life do not become resources at our disposal simply because we are technologically capable of reaching them. Decolonization therefore opens up the possibility of thinking about space research not as a continuation of conquest, but as a form of exploration that connects knowledge, protection, and responsibility.

When people talk about water on the Moon or Mars, terms such as “resource,” “discovery,” or “development” quickly enter the conversation. Do we need to develop a new language?

Yes—or at the very least, we need to think more consciously about the kinds of futures our language already projects. Terms such as frontier, “development,” “colonization,” or “resource” carry ideas of expansion, ownership, and availability into space. But we can also speak of preservation, sharing, care, encounter, and collaborative exploration. Perhaps we should learn to understand ourselves in the cosmos less as conquerors and owners, and more as part of a cosmic reality that does not belong to us.

Images of Outer Space

Many images from space appear immediate and objective—even though they are technically produced, processed, or assembled from data. What kind of idea of objectivity does this create?

Images of space can give the impression that we are seeing the universe directly and objectively—as it actually is. Yet telescopes, sensors, spectrometers, data, and algorithms make visible phenomena that our eyes would not be able to perceive at all. This does not make these images any less scientific, but it does show that objectivity is not an unconditioned “view from nowhere.” Scientific seeing is materially, technologically, and epistemically mediated—and precisely for that reason, we must also ask how visibility is produced and what remains invisible.

Long before we find extraterrestrial life, we already have images of it in our minds. How strongly do such images shape what researchers look for? Can images also expand our understanding of life?

Images shape what we are able to imagine as life in the first place—and therefore also what we search for. In doing so, we often project terrestrial ideas of bodies, landscapes, and habitability onto other worlds. Research on exoplanets, however, shows that knowledge does not begin with direct visual perception: spectra and other measurement data are used to develop ideas about possible atmospheres and biosignatures. Such visualizations can broaden our perspective—including our awareness that life may be very different from what our familiar images lead us to expect.

Your research connects space research with gender studies. What role do ideas of gender play in images and narratives of extraterrestrial life and other worlds?

Visions of space always also tell us something about what we understand by being human and about the cultural, religious, and gendered ideas we hold about the future. Historically, exploration, technological mastery, risk-taking, and conquest have been strongly associated with hegemonic masculinity. Today, this connection can also be found in technocapitalist visions of a multiplanetary humanity, such as those developed by private space companies. At the same time, we must ask which bodies, genders, relationships, sexualities, and forms of reproduction are represented in such visions of the future at all. Gender does not simply travel with us into space; rather, space reveals which ideas of humanity we carry from Earth into the future.

Which images of water in space or of extraterrestrial life have been particularly formative for you personally—and why?

I am fascinated by images that take us to the limits of the visible: traces of past water on Mars, spectra of distant exoplanets, or visualizations of the invisible universe. They lead us toward a reality that extends far beyond what our eyes can perceive directly. I am particularly moved by the thought that the universe itself continues to expand. Through instruments, data, and models, science makes some part of this immeasurable reality perceptible. Perhaps that is precisely where the beauty of these images lies: they show us not only the cosmos, but also the limits of our own vision—and at the same time expand it. What else might we learn to recognize as life if we are willing to see differently?

Prof. Dr. Ulrike Ernst-Auga

is a scholar of cultural and religious studies and Professor of Religious Studies and Intercultural Theology at Humboldt-Universität zu Berlin. She is also active in a range of international research contexts. Her research brings together religious studies, gender studies, and postcolonial epistemologies with questions of visuality, digitalization, and space research.

At the Langen Nacht der Museen Ulrike Ernst-Auga will appear at the Humboldt Labor as part of the “Meet the Scientist” format. Her contribution „Wer entscheidet, was Leben ist?“ (“Who decides what life is?”) focuses on questions of astrobiology, extraterrestrial life, and the scientific and cultural ideas that shape how we look at life in space.