Posted by: dacalu | 19 April 2012

Astrobiology and Meaning

Today I had the privilege of addressing the Astrobiology Science Conference (2012, Atlanta) on the topic of astrobiology and meaning.  The talk was part of a memorial session commemorating 12 scientists who have passed away in the past 2 years.

I must apologize for being unable to include the slides.  The bracketed words between sections indicate a slide advance for the presentation.  The content should be understandable without it.


In memoriam Baruch Blumberg, Elisabetta Pierazzo, Bob Shapiro, David Gilichinsky, James Scott, Lynn Margulis, Michael Drake, Ron Greeley, and Susan Niebur.


Astrobiology and Meaning


[Title Slide]

In daily life we rarely have opportunities

to think about the important questions,

the big picture issues of life and meaning.

For most of us, it’s a matter of looking at a very narrow slice of the universe –

if we are lucky, doing experiments or making observations

more days than not;

if we are less lucky getting caught up in the politics of funding,

and teaching, and institutions

in a way that can distract us from the things we care about most.




How many of you can identify with this comic from XKCD?

It must be said that science is hard.

And astrobiology can be particularly hard,

because, often, the questions we ask are so big

relative to the data we have.


[Data à Planet]

It can be easy to get sidetracked from our initial passion.

I’m guessing for most of you, that’s a passion for

understanding the universe,

not just collecting facts,

but really forming a serious and solid

intuition for the way things are.

For others, there is a deep desire to communicate

these essential truths about reality,

for forming a connection with students, educators

and, on occasion, even policymakers

so that the work of the explorers and innovators

can spread out to other people as well.


That passion gets played out in the daily work of science,

taking a small but digestible bite out of the big issues

and making progress.

Not terribly glamorous, but useful, important,

and surprisingly fulfilling.


[Photo Slide]

Today we remember nine people who found the work fulfilling,

nine people who shared a willingness to understand the universe,

a sense of perspective, a sense of humor,

and an incredible talent for taking all those little pieces

and making them into a meaningful whole.

Barry, Betty, Bob, David, James, Lynn, Mike, Ron, and Susan.


Astrobiology can be a funny business.

Some have said that we study nothing

–       after all, we have not discovered any extraterrestrial life.

Those of us who do astrobiology

know that that is the opposite of the truth.

In some ways we study everything.

We’re trying to create a coherent whole

out of astronomy, biology, chemistry, planetary science,

and many other disciplines.

I’m not sure that’s any more satisfying.

Too much, or too little.


[Roadmap Questions]

The NASA Astrobiology Roadmap highlights these three questions:

How does life begin and evolve?

Does life exist elsewhere in the universe?

What is the future of life on Earth and beyond?

That narrows things down a bit.

It’s clear that we are dealing with life in the universe.

But I must confess – I’m still a bit dissatisfied,

and always have been with these questions.

They seem a bit too broad.

“How does life begin and evolve?”

sort of covers everything, doesn’t it?

“Does life exist elsewhere in the universe?”

That’s a yes or no question.

Currently the answer is “maybe.”

“What is the future of life?”

Heat death.  In the meantime, very hard to predict.


[Life in Space]

So, in my book, I settled on the idea that astrobiology

was the study of life in space –

that is looking at life as it happens to planets,

or perhaps other bodies floating in the void.

Earth, from this perspective, is a single instance of life,

a single data point,

immensely informative, but still only one example.

Astrobiology involves characterizing that example,

while looking for another one.

I still use that definition, but it shares some of the same problems

as the roadmap definition.

It doesn’t hit home quite squarely enough;

nor does it convey what astrobiology is

without explanation;

nor, perhaps does it do justice to the rather large

body of information we possess

both about Earth and other stellar systems.



What then, is astrobiology?

Let me propose that astrobiology involves making pictures of the universe

– pictures in which life appears in context.

It’s something like cosmology in the older sense,

a discourse on the arrangement of the world,

but with a particular eye to scientific modes of understanding.

Astrobiology, then, would be a mosaic of scientific theories,

that we piece together to explain life.

It’s a way of putting living things, including humanity, in context.


[Aristotle and Lucretius]

This is not a new endeavor.

Aristotle and Epicurus were talking about

the nature of life in the universe over 2000 years ago.

Each tried to use observations about the physical world

to explain the origin, extent, and purpose of life.


From Aristotle we get many of the categories we currently use:

species and spherical planets and causal chains,

natural motion, physical substance.

On the other hand, Aristotle also thought

that the universe was steady state and eternal,

that things had inherent purpose,

that immaterial souls caused movement,

and that nothing at all existed

beyond the sphere of the stars.

Earth was the center of the universe.


Epicurus’ follower Lucretius gave us an entirely different picture.

He introduced a kind of cosmological principle,

saying the rules and the stuff must be the same everywhere.

He proposed an infinite cosmos with a finite history,

a cosmology reduced to particles and universal forces,

life arising from non-life,

and an infinite variety of inhabited worlds.

On the other hand, Epicurus thought

that the world was flat and falling through infinite space,

that worlds, like women,

formed wombs from which animals sprung,

but only during their childbearing years,

and that material souls could be formed from soul seeds

and cause particles to swerve from their original course.


I’m not trying to convince you that one was right,

or to show you how silly ancient Greeks were.

I’m trying to tell you that we are asking the same fundamental questions

that humans have been asking for all of recorded history.

Should we describe the universe as alive, with quiet bits?

Or as mechanical with animate bits?

Where does life come from?

What are the boundaries that separate and define the cosmos?

Is our little portion of space unique?

Are we alone?


[2 Yggdrasil Images]

The word “world” has a fascinating history.

It comes from the Old High German Weralt, translated by JRR Tolkien (and others) as the “Age of Man” or the present age.

Perhaps it would be more accurate and politically correct to render it as the context of humans.

For the Old Norse and Old English, this was Midgard, the middle enclosure on Yggdrasil, the universe tree.



For Aristotle and Ptolemy, it was a spherical locus of life –

At least life as we know it –

surrounded by a great firmament of crystalline spheres

The important events occurred on center stage.



For Dante and other medieval thinkers, it was an Earth encysted hell, fallen out of a boundless expanse of divine reality.

Not only was the world ordered, it was hierarchical.



Copernicus – with the help of Galileo, Kepler, and Newton –

moved Earth out of the center

so that the world meant what we now think of as a solar system.



Later, with the help of William Herschel (1738-1822) and Edwin Hubble (1889-1953), we came to realize that even the solar system was orbiting the center of the galaxy, and even the galaxy was one among many.

Our central location had – and has – been lost,

to the exigencies of astronomy.


The current astronomical cosmology looks something like this.

[WMAP + Cosmological Constant Equation]


And the world, once the entire experience of humanity, resting in a tree,

looks something like this. [Pale Blue Dot – Google Pale Blue Dot if you want to see this image of the Earth taken from the Voyager spacecraft.]

As of last week, the exoplanet encylcopedia listed 763 confirmed extrasolar planets.  Kepler reports over 2000 candidates and the number is growing daily.

World means something different now

and astrobiologists continue to play a role in changing it.


What I’m trying to say – with far too much academic verbiage –

is that astrobiology falls in this tradition,

we are in the business of making meaning.

Most of the time we work in our own individual bailiwicks,

producing knowledge

about basalt or bacteria,

planets or parasites,

engineering or evolution.

We do the slow hard work of turning observations into knowledge,

but every so often, we get together and compare

those shiny little pieces of understanding,

and try to assemble the bigger picture.


[Planets and Life]

In the introduction to Planets and Life, Sullivan and Baross say that

“Astrobiology is the scientific discipline of optimism –

optimism that the grand questions are not only fundamental, but tractable”

It would be insufficient to say that we are continuing

in the footsteps of Aristotle and Lucretius.

After all, Dante did that too.

I want to say that we add the particular benefit of very carefully

piecing together a scientific view of the universe.

The task of figuring out which questions may be addressed



[What is Life?]

We don’t just ask, “what is Life?”

We ask, “is this life?”  [ALH84001] “is that life?” [Hepatitus B Virus]

And what about this [Prion]

“What would it take to convince us?”

We ask “can we make it in the lab?”

We don’t just ask “is there life elsewhere?”

We ask what conditions are like on Mars [Whirlwind?] and Europa and Gliese (glee-za) 581c and we make observations.


Our pictures of the universe look a little different these days.

We’re more comfortable talking in equations and schematics,

but we’re in the same business of constructing models

for the context of humanity, and beyond.

Here is another modern conception of the world.


[Tree of life based on SSU rRNA sequences]

Perhaps you don’t think of the expanding universe and the tree of life as worlds, or as the sociologists say, “constructed worldviews.”

But they are.  Both are examples of mountains of data that have been condensed into a few thousand pixels.  Both represent human understanding of our place amidst the stuff of life.


[Little Metabolism]

Perhaps you like this picture of life better?

It’s a simplified schematic of terrestrial metabolism?


[Large Metabolism]

Or this one.  After all, more data is always better, right?

Does this answer the question, “What is life?”

Does it answer the question of how we relate to the universe?




We’re in the business of asking the big questions, the old questions,

the fundamental questions, in new ways – in scientific ways.

We’re in the business of consolidating the work of thousands

in astronomy, biology, chemistry, physics, planetary science,

and many other disciplines into one, comprehensive picture

of life in the universe.


I firmly believe that astrobiology has the long perspective.  I will never forget Jerry Soffen telling me that he knew this endeavor would take generations.  He took pride in the beginning – or at least new beginning – of a project that would take hundreds of years.  That was one of the things that inspired me to be an astrobiologist.

Each new planet, each new extremophile discovered convinces me that, perhaps, we’re asking the right kind of questions,

even if we don’t have the answers yet.

Like many of you, like our colleagues who died, I delight in the big questions,

and I delight in the fine balance of pushing our knowledge

just a little bit farther than we thought we could –

without, of course, going too far.


[Bones McCoy]

“It’s life, Jim, but not as we know it.”

An old joke, I know, particularly in this crowd,

but I wanted to emphasize the fact that we are explorers

in the physical sense, in the scientific sense,

and even in the philosophical sense

What we’re looking for is something like the life we know

– otherwise, we would never recognize it.

It’s also something different

– otherwise we wouldn’t care.

I can’t express enough the importance of this kind of thinking.

In an age of specialization, we are training people to

think critically across and between disciplines.

We are building a community.

Barry and the others devoted countless hours,

not only to the search for truth,

but to founding a society of broadly educated,

insanely curious,

progress and technology minded,

scientific meaning makers.

Sara Walker said just yesterday,

in the meeting of early career astrobiologists,

“It’s really because the community is so awesome

that these things work.”

She was talking about AbGradCon,

and the Astrobiology Primer,

and version 2 of the Primer (nearing completion),

and S.A.G.A.N.,

and a host of other projects,

including the notion that all of us might manage

to communicate enough to put together

a common picture of the world.



We remember Barry, Betty, Bob, David, James, Lynn, Mike, Ron, and Susan.

for their contributions to our picture of the universe.

Each one of them added something important

to the scientific mosaic.

They revolutionized our understanding of

cells, disease, habitability, planetary dynamics, life.


[Drake Equation]

Perhaps you’re familiar with this picture of the universe – the Drake Equation.

We’ve come a long way since Frank proposed this in 1961.

We’re training a new generation of scientists,

who see this as more than characterized uncertainty.

They see it as a challenge.



Each of the people we remember today was involved

in training and inspiring others.

They were mentors and advisors and inspirational teachers.

They set the stage for an age of discovery

unlike anything we’ve seen before.

Perhaps we’re not going to revolutionize the world

the way Aristotle did, or Copernicus, or Hubble

But I do think we’re in the business of rewriting the heavens

in a way that makes them more transparent, more real,

and more accessible.



And for all the high-falutin talk,

I have to say, most of us do it simply because it’s so much fun.

We find the universe interesting, and we want to figure it out.

We sit around drinking and talking about the cosmos.


[Apeds 2006]

We spend our free time working on astrobiology projects

with other people who find the big questions fascinating.

And we reach out to others.

Forming collaborations [A-Niebur]

And friendships [A-Pierazzo]


I have found a greater concentration of people in astrobiology

who truly care about what they do

who have an intense passion for the work

and for the community

than in just about any other endeavor.

People who want to ask the big questions.

People who want to study the universe concretely and

…(in carefully controlled environments)…

speculate wildly.

It’s exciting to be able to consolidate knowledge in new ways,

and it’s a pleasure to work with people who think critically

and creatively at the same time.



It’s hard to say what our cosmology

– our model of the world –

will look like in 10 years time,

much less 100 years in the future.

I cannot say, but I am thoroughly convinced that astrobiologists

will play a large role in putting it together.


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