Is Life an “Artificial Category”?
“Nobody has a handle on exactly what has happened in the history of this planet.”
– Maggie Turnbull, Wisconsin Public Radio
I first heard Maggie Turnbull speak at the 2008 World Science Festival and found her thinking about the Universe as a “continuum” refreshing. I was fascinated that she’d only just received her PhD in 2004, was living with her parents in the north woods of Wisconsin where she was “making no money,” yet was onstage giving crisp cosmic perspective on the “laws of life” alongside luminaries Paul Davies and Steve Benner, with John Hockenberry as maestro.
But then NASA consultsTurnbull and her 2002 HabCat catalog (based on Turnbull’s PhD thesis) as a guide to habitable star systems. And, Turnbull’s interest in space science goes back decades, to kindergarten, where she first discovered an encyclopedia of the planets (though the Suzuki violin would vie for her attention in elementary school).
SciFi was also an influence, in particular Carl Sagan’s novel Contact, which was made into a movie by the same name with Jodi Foster, whose character was inspired by HabCat co-creator Jill Tarter, the now outgoing chief of SETI (Search for Extraterrestrial Intelligence).
HabCat catalog grew out of the European Space Agency’s Hipparcos space astrometry mission in 1989 and resulting Hipparcos catalog, which charted 118,000 stars, followed byTycho catalog with more than two million stars plus details on ESA’s Celestia 2000 CD-Rom.
The herculean task for Turnbull was sifting through all these stars and identifying the most habitable systems, fleshing them out using as criteria: x-ray luminosity (most important), color, rotation, metallicity and other features. More recently, she winnowed the candidates to two lists of five: (1) Beta Canum Venaticorum, HD 10307, HD 211415, 18 Scorpii, 51 Pegasi, and (2) Epsilon Indi, Epsilon Eridani, 40 Eridani, Alpha Centauri B, Tau Ceti.
In addition to serving as a consultant for NASA’s New Worlds Observer mission to discover Earth-like planets, Turnbull also advises MIT in its search for transits of habitable exoplanets. Her headquarters are at Global Science Institute, the non-profit research organization she created at Antigo, Wisconsin. Turnbull and a small team at GSI now devote the bulk of their time to science education, environmental preservation and sustainable development, but Turnbull likes to think of GSI as a future NAI (NASA Astrobiology Institute). She is also active in community affairs in Antigo as an alderperson on City Council.
Maggie Turnbull’s BS degree is in astronomy from the University of Wisconsin-Madison. Her MS and PhD are also in astronomy, with a minor in cell biology, from the University of Arizona. She was an NAI Postdoctoral Fellow at Carnegie Institution’s Department of Terrestrial Magnetism.
My conversation with Maggie Turnbull follows.
Suzan Mazur: You have an asteroid named after you 7863 TURNBULL. Congratulations.
Maggie Turnbull: Thank you.
Suzan Mazur: Located somewhere between Mars and Jupiter?
Maggie Turnbull: Right. That’s the asteroid main-belt.
Suzan Mazur: What’s the asteroid made of and is it habitable?
Maggie Turnbull: Definitely not habitable. Far too small. There’s always the possibility of internal cracks and crevices filled with ice or ice water that could conceivably be utilized by microbes, but I’m going to say, no, this is not a habitable object. There are thousands of these asteroids in the main-belt between Mars and Jupiter. Composition-wise, most are what we call carbonaceous and are rich in organic compounds and silicate minerals.
Suzan Mazur: It was named for you by whom?
Maggie Turnbull: By Brian Skiff, who discovered the asteroid in 1981. He’s at Lowell Observatory in Flagstaff, Arizona. The way it works is that an asteroid discoverer gets to chose its name whereas comets are automatically named after the discoverer.
Suzan Mazur: Were you were brought up in a science family and when did you first develop an interest in astronomy?
Maggie Turnbull: Dad is a medical doctor and has always been very interested in science and the natural world. He’s collected butterflies for a long time. Very outdoorsy. Mom likes numbers, she’s an accountant. I’ve been curious about space from a very young age. I remember being fascinated by an encyclopedia of the planets in kindergarten.
Suzan Mazur: When did you get your first telescope?
Maggie Turnbull: I didn’t have a backyard telescope growing up, so I kept myself occupied with books about science and nature. Pictures from the big scopes, plus imagination, kept me excited about space.
Suzan Mazur: You were brought up in Wisconsin?
Suzan Mazur: You’ve indicated that the laws of life are being drawn too narrowly, saying you “mentally resist” defining the parameters of life because so far we only have one example of it — life on Earth. You’ve also said that “as scientists we always want to categorize everything, but is it possible that it’s just a continuum of a one-based system?” Would you expand on those comments?
Maggie Turnbull: It’s a very human tendency to want to put things in categories: This is alive and this other thing is not alive. But those categories are artificial. The Universe does not know anything about those categories.
We want to be thinking in terms of a continuum. That continuum can be along whatever parameter — different behaviors, different relationships with other parts of the system. But defining life as a category — as something in a box and whatever is outside the box is non-life — will continue to produce exceptions.
By some definitions, a human would not even be considered to be alive. If only one human were in a box in space, there’d be no way that human could reproduce. A single human would in that instance not fully qualify as a life form.
Even though categorizing things according to specific characteristics is useful for organizing human thought, it will never allow us to describe the whole system. We need to get over our obsession with defining things as living and non-living.
Suzan Mazur: As an independent astrobiologist what is your affiliation with NASA?
Maggie Turnbull: I started a small non-profit, non-academic organization here in Antigo several years ago called Global Science Institute. I have a cooperative agreement with NASA for research related to questions NASA is interested in.
Suzan Mazur: NASA’s official definition for life is no longer still limited to “a self-sustained chemical system capable of undergoing Darwinian evolution,” is it?
Maggie Turnbull: All I can say is, if NASA has an official definition of life, I don’t agree with it, and neither does life.
Suzan Mazur: Would you know if NASA is still financing and otherwise supporting research pegged to the Darwinian model?
Maggie Turnbull: I don’t know exactly what you mean by “pegged to the Darwinian model.” NASA supports research in genetics and in mechanisms that allow for survival in extreme conditions.
It’s really all about our collective desire to investigate things and the technology catching up as well as our understanding of how the Universe works. Scientists in many ways are their own worst enemies. There’s so much disagreement in the scientific community because of all the objectives being pursued simultaneously. Often the result is a loss of focus. Scientists end up rehashing the same questions and the mission disappears.
For example, the mission concept I’ve been developing the past few years is one where most of the technologies are now available and it’s a matter of organizing those technologies to demonstrate that they can be effective in combination to observe Earth-like planets around nearby stars. Not far-away stars like with Kepler, but the stars you can see with your naked eye. In order to do that we need a more collective agreement that we’re going to invest in such a mission.
Suzan Mazur: Are you mostly privately funded now?
Maggie Turnbull: No, NASA is the big game in town for astrophysics research. The Global Science Institute has been funded by private donations to carry out other community projects, however.
Suzan Mazur: How much funding are you currently receiving from NASA?
Maggie Turnbull: There are a few grants, primarily through the NASA Astrobiology Institute. There are different teams funded by NAI.
Suzan Mazur: Are we talking about a few million dollars?
Maggie Turnbull: I am certainly not making millions from doing this work. One of the teams I’m working with right now is at Arizona State University and those are five-year awards of $1 M – $1.5 M a year for the whole team of 20-30 collaborators plus students.
Suzan Mazur: Funding of origin of life research is increasingly a contentious issue because there’s a schism between the neo-Darwinists on one side and on the other many of the evo-devo scientists, symbiogeneticists, geologists, mechanical engineers, natural scientists, cognitive scientists, linguists and others. Would you comment?
Maggie Turnbull: I don’t know much about it. I’m really an astronomer at heart. My focus is on the stars. I have very simple objectives when it comes to finding habitable planets and whatever the biologists want to say about the evolution of life is fine with me. At the end of the day though nothing matters until we find it.
Suzan Mazur: Until we find what?
Maggie Turnbull: Until we find life on another planet.
Suzan Mazur: So you don’t think that much about origin of life issues.
Maggie Turnbull: I think about origin of life, but personally I’m more interested in exploring other environments and finding out whether there are life form systems there. Evolutionary biologists would get a lot out of that search as well. I’m looking for the variety of life in the Universe.
Suzan Mazur: How much of science would you say is social momentum, i.e., not objective?
Maggie Turnbull: I would say a lot of it is social momentum because science is about a community of thinkers. By thinkers I mean scientists as well as non-scientists. Because when the American public is keenly interested in something, it is much easier for Congress to make the case for funding it. What scientists want, however, often does not concur with what the public wants. I don’t mean to be harsh in saying this, but the truth is that when scientists want to do what they want to do, they try to sell it as something the public should care about.
It takes so long to get a PhD and to build a career in science. Once that’s achieved, a scientist is hemmed-in as far as what they’re expert at and able to work on. A scientist can’t easily reorient their research just because the American public wants to study something else. So scientists try to persuade Congress to pay for the research they want because that’s what they know how to do. Scientific progress thus is 99% a wait for consensus.
Suzan Mazur: What is the closest and most habitable star you’ve identified?
Maggie Turnbull: It depends on how you define habitability — (1) everything is just right for a technological civilization having evolved on a planet, or (2) a system that could have planets in the habitable zone. In the latter case, I’d say it could be a star system as close as our nearest one, Alpha Centauri. However, there are three stars in that star system. And even though the habitable zone is technically stable and safe around all three of those stars, and those stars are close together, it’s hard to imagine how water would be delivered to planets in the habitable zone.
All of our oceans, for instance, resulted from water being released from asteroids and comets impacting Earth and originating further out in the solar system. But if Earth were a system of three stars, like Alpha Centauri, water might have been ejected from the system and Earth could now be dry because we didn’t get those water deliveries from comets and asteroids.
It’s important to look at the whole system and assess. Alpha Centauri is interesting just because it’s the nearest star. There’s no way we can not look at it. It’s a sun just like our own. We have to look at it. But in terms of habitability, we do have to be skeptical.
Suzan Mazur: How well is the SETI program working out engaging 60,000 citizen astronomers to search for ETI (Extraterrestrial Intelligence)?
Suzan Mazur: We now have one Hollywood director venturing into the mining of asteroids. Do you expect that we will seriously reinvigorate anytime soon the visionary plans from the late 1970s,i.e., space colonization and Gerard O’Neill‘s ideas?
Maggie Turnbull: It seems so. SpaceX, the private space transport company, is a perfect example. Finding the technology that gets us into space in an increasingly affordable way is of great interest. How could it not be?
There are resources out there that we could use in order to continue growing as a civilization. Whoever in the private sector figures out how to access them stands to make a huge profit. The success of such a venture will revitalize space exploration. We need to look to the private sector to fund these projects. Government resources alone are no longer sustainable.