Tthe astrobiologist Nathalie Cabrol was born in 1963 and grew up near Paris. She completed a PhD at the Sorbonne on the evolution of water on Mars and moved to the USA in 1994 as a researcher at Nasa Ames. She has worked extensively in the Atacama Desert and the Chilean Andes, investigating how life adapts to extreme environments analogous to those on other planets. Cabrol, who lives in Northern California, is now the director of the Carl Sagan Center at the Seti [Search for Extraterrestrial Intelligence] Institute. Her latest book, The secret life of the universe: An astrobiologist’s search for the origins and limits of lifewill be published on August 15.
How did you become interested in the heavens?
It is not difficult to be interested in the heavens, we are in the heavens! I remember watching the sky, five or six years old, and starting to ask myself, “What is this all about? Why does it exist?”
If you’re looking for extraterrestrial life, it’s a mistake to just look for it Earth-like planets and life as we understand it?
It’s not necessarily bad to look at our biochemistry and the kind of environment that brought us here. Astronomy tells us that the stuff we’re made of is so common, and we learn that carbon was created much earlier than we thought. And with the discovery of exoplanets [planets outside our solar system], we also realize that, while there is probably no exact replica of Earth anywhere in the universe, there are environments that are probably just as suitable for life, or more so. But from that point of view, we pinch ourselves to look for another version of ourselves. I look more at the universal markers of life – markers that will be true anywhere in the universe, regardless of biochemistry.
What makes you so sure there is something out there, rather than nothing?
The easy answer is Carl Sagan’s response: “It would be a terrible waste of space.” We have been intellectually searching for life for thousands of years, but have only been searching in a meaningful way with technology for 60 years, so this is a very young search. You also have to look at the distances. Even if it is by some miracle [alien life forms] think and communicate in similar ways to us and are interested in what is happening around them, our radio bubble is barely 200 light years across. It is small. Then there is the fact that we are looking for life, but we don’t really know what life is, or intelligence, or even less consciousness. We have no idea what those three things are. We’re still looking for them, which is good, because otherwise you’re not going anywhere.
Where in our solar system would you most expect to find life bubbling up?
I believe that Mars still has some big surprises for us. They won’t be on the surface, but unlike a lot of people I don’t think it’s going to be that far down. There is still volcanism on Mars and we know that there is water and lots of nutrients – magnesium, potassium and so on. Elsewhere in the solar system, Europa [a moon of Jupiter] may have an oxygen-rich ocean that offers a chance for more complex life to evolve. It also has sources of carbon.
We are talking about oceans under miles of surface ice.
Yes. And the thing is, you don’t have to invest in submarines to explore it; you can let mother nature bring you the goods. Because of the gravitational tides on Europa, you have these convective movements and a kind of slush that comes to the surface regularly. You land next to it, grab that stuff and see what’s there. You let the sea come to you.
But Enceladus [a moon of Saturn] is definitely my favorite. I love it because it just throws stuff at you in geysers or plumes [shooting up from the surface]. Obviously, slowing down a spacecraft to grab monsters is pretty complicated, but we can do amazing things on Enceladus.
Other planets give us lessons about what to expect global warming on earth?
If you look at what happens to a planet when a runaway greenhouse effect occurs, it’s Venus. And the planet that’s too hot that’s losing its water, that’s Mars. We have it right before our eyes.
What is your view on people like Elon Musk talking about colonize other planets?
Well, first of all, I hate the word colonization. And the idea of putting outposts on another planet because we’re escaping our own is an affront to the spirit of exploration. Migrants usually move because they are desperate for better conditions. This is not the case on Mars. It’s much worse. I think that we should go to Mars not because it is an easy escape, but because we have grown up and we are using it as a training ground for a much more mature civilization to take its first steps to become interplanetary, and later, interstellar. But we also need to use all that technology to look back at Earth.
Projecting ourselves into space challenges our brains to find solutions that we wouldn’t otherwise look for on our planet. Sure, send a Tesla into space [as Musk did in 2018] was not the right message when trying to create space policy and prevent planetary contamination.
There has been a lot of excitement about UAPs [unidentified anomalous phenomena] recently. Do you pay much attention to it?
As a scientist, UAPs are interesting to me because we must first accept them for what they are: unidentified phenomena. The leap I’m not making is to say that these are necessarily extraterrestrial phenomena, as in flying saucers and so on. We know that 96% of them will find a natural explanation. One thing to consider is that we are seeing a lot more unusual atmospheric phenomena because our planet is changing. And then there are unknown government activities that you were not supposed to see. Finally, there is the half percent or so that is unexplained. Of course I’m interested.
But Seti doesn’t like aerial phenomena – our instruments are pointed much further away. I always say, jokingly, that we look for ET in its own habitat, while people looking for UAPs try to see ET in ours. But if you tell me tomorrow that you have irrefutable evidence of an alien spacecraft caught on video somewhere, I will be the happiest person in the world.
