Finding Life Outside, Page 3

Our Future in Space: Finding Life Outside

Alexander Pavlov

Astrobiology is a new direction in science, which is really on the border of biology, astronomy, planetary science, and atmospheric science. People are interested in the origin of life and specifically how life evolved together with the environment, and whether life can be present on other terrestrial planets like Mars or elsewhere in the universe.

You really have to go to the boundaries of these disciplines to answer those questions. That’s why NASA has this new initiative to essentially sponsor that new direction which we call astrobiology. My interest in the astrobiology is from the climate standpoint. I want to know what kind of environment and what kind of climate was there at the moment of the origin of life, at the early evolution of life in particular.

The main interest is to study Mars, because Mars—I won’t say it’s the only place we expect to find extraterrestrial life in the solar system, but it’s the most reachable place. There are other potential places like Titan and Europa, but they’re much further away, although they’re extremely interesting as well.

But Mars is relatively accessible and there’s a whole kind of express of missions that’s being developed. It is important to know where exactly you’d expect some kind of life, if life was there. There are all sorts of questions we can get from the atmosphere. The discovery of methane on Mars is a very strong indication of life. But is that true? Is it confirmed that this is a direct sign of biology, since methane is a biogenic gas? So there are a lot of things that atmospheric science can give you. That’s why I see myself entering into this field.

The beauty of astrobiology is that you can have an idea and you’re working with scientists in different disciplines, biologists in particular. Biologists don’t know anything about planets or the Martian atmosphere, really. But if you know how the climate works and what to expect on the Martian surface, you can give a biologist a clue on how to set up a particular experiment in order to test what particular bugs are going to live there or not.

I think there’s a very strong indication [that there could be life on Mars]. There are so many suggestions that, well, the UV radiation is a problem, lack of water is a problem, ionizing radiation, superoxidants is a problem. It is a harsh place, there’s no question of that. It’s cold there. But the more we start learning about extremes of life, we’ll be smarter where to look. Don’t go to directly the surface, go a little bit underneath. You have ice there. The water is maybe not stable at the Mars surface because of the very low pressures. But if the ice is underneath, all of a sudden we have a layer that has water in it, liquid films. Yes, it’s not as stable as an ocean, but how much do you really need for the microorganisms to survive? Not much.

When you start doing all this, then the objections that people have about life on Mars kind of fall. You find out that, yes, there are bugs here which live in the Siberian permafrost, with conditions very similar to what’s there. There are microorganisms that can take extremely high dosages of radiation. The fact that Mars doesn’t have a magnetic field, and a very thin atmosphere bombarded by cosmic rays, is really nothing strange either. So really there’s no reason why not. I think we’ll be witnesses to this kind of discovery being made.