The scoop: Somehow life in the solar system managed to arise, develop and evolve here on Earth. But is life less of a miracle, and more a matter of inevitable chemistry?
We chat with James Trefil, a physicist at George Mason University who is collaborating with others on the question of life's origins.
Dave on Earth (10:00 AM): Hi Dr. Trefil!
Can you see my message?
Why Science Guy (10:02 AM): Good morning -- yes, I can see your text.
Dave on Earth (10:04 AM): Excellent! Let's get started.
So is it rainy and gloomy where you're at? Because it's been like that here, for days. Feeling a bit stir-crazy.
Why Science Guy (10:04 AM): Yeah-- fortunately, I cut the grass on the last dry day -- it's going crazy!
Dave on Earth (10:05 AM): Good call -- otherwise your house might be hidden in a prairie
Why Science Guy (10:05 AM): Maybe so... it tends to get away from you this time of year
Dave on Earth (10:05 AM): Right :)
Speaking of things growing, we're here to chat about the origins of life.
You've done a lot of writing about science, and on the universe in general.
Most recently, you helped write this article on the latest idea regarding the origin of life.
Why Science Guy (10:07 AM): Yep! I started writing for Smithsonian many years ago, then went on to books.
The origin of life article is part of a large National Science Foundation grant -- it's called Frontiers in Integrative Biological Research.
It's made up of people from George Mason University, the Santa Fe Institute, Carnegie Foundation, and other institutions.
It's devoted to working on the origin of life problem.
Dave on Earth (10:09 AM): Interesting choice of words in the article, and in your last message...
In the article, the idea is that life is inevitable, and discovering why seems to be a problem.
In our solar system, was life inevitable? And what are the problems left for us to figure out?
Why Science Guy (10:11 AM): There is a longstanding dispute in the scientific community on the issue of chance vs. necessity when it comes to life.
Stephen J. Gould argued, "If you played the tape again, you'd get a different tune."
The main thrust of the Santa Fe group is that this isn't true for the origin of life.
Life develops according to known -- or at least knowable -- laws of chemistry and physics, and will arise wherever conditions are similar to what they were on Earth.
I guess we'd argue that life was inevitable of Earth.
Maybe on early Mars as well.
I don't think we have anything to say yet about Jupiter's moon Europa, which is the best hope for other life in the solar system.
Dave on Earth (10:14 AM): Now that's a quite a concept to chew on:
Given the right conditions, life is as inevitable as -- to recall grade school volcano experiments -- getting carbon dioxide when vinegar meets baking soda?
Why Science Guy (10:14 AM): Eric Smith (Santa Fe) posed the origin of life problem in an interesting way:
"What problem was there on the early Earth that was solved by the appearance of life?"
The problem is basically that geophysical processes push electrons in atoms to high-energy states, and life is the best way for them to get back down.
That's the basic idea, at least as far as origins go -- life is just basic chemistry.
I like to put it this way:
The chances of finding enough gold atoms in one place to make a ring, assuming pure chance, is something like... one chance in 10^123 (one followed by 123 zeros!).
However, we can make gold jewelry because the assembly of atoms isn't random. Rather, it's governed by well-known laws of chemistry and mineralogy.
In other words, the fact that a woman as classy as my wife said "yes" when I proposed may be a miracle, but my ability to buy a gold ring isn't.
Dave on Earth (10:18 AM): Ha! That's a good analogy to remember, for sure.
Now about life helping with "atoms in high-energy states."
Can you offer up an example?
Why Science Guy (10:18 AM): I have an example in my notes, but I want to make sure I get it right.
It basically involves carbon dioxide-- I forget the details...
Dave on Earth (10:18 AM): No worries. Want to grab your notes?
Why Science Guy (10:19 AM): I'll go get them now.
Dave on Earth (10:19 AM): Great!
Why Science Guy (10:22 AM): Ok -- carbon dioxide and hydrogen are produced in deep sea hydrothermal vents.
The energy of the system can be lowered if the electrons in the hydrogen "roll down the hill" to bind with carbon dioxide and form acetate.
Problem is, this is a very slow process (ordinarily). But it's quick in the presence of life.
So: The problem is that the electrons are stranded in a high energy state, the solution is provided by life.
Dave on Earth (10:23 AM): So in your example (and I'm guessing there are others), life is the most simple and efficient way to get rid of that "high-energy" state?
Well, "simple" being a relative term.
Why Science Guy (10:24 AM): That's one hypothesis that drives the work of the Santa Fe group
Dave on Earth (10:24 AM): So where do you fit into the Santa Fe group?
And what are the other ideas competing with those generated by it, at least in regards to the origin(s) of life?
Why Science Guy (10:27 AM): I'm basically the public outreach guy. I like to say that my goal is to be the Huxley to Morowits and Smith to Darwin :)
The main competing theory -- and one likely supported by most scientists in the field -- is the ribonucleic acid (RNA) world.
In this scheme, an RNA molecule (a critical component in life as we know it) assembles by chance in a prebiotic soup.
After that chance occurrence, it acts as an enzyme to drive chemical reactions.
This is an example of a theory depending on chance rather than necessity.
The construction of the original RNA is seen as a random event, but the laws of chemistry operate after that.
Us? We want necessity to operate right from the start.
Dave on Earth (10:28 AM): Thanks! Now I'm thinking about a specific part of your article.
You postulate how to explain how the U.S. highway system came to be, and the common approach is to explain why roads lead to cars, and cars lead to roads.
But that's backwards -- you have to look all the way back to the start of roads, beginning with foot trails, then wagon roads...
Then
where cities arose.
And how the needs and nature of those roads changed slowly over time...
Until a highway system is more or less inevitable.
But the take-home point seems to be: Little tiny incremental baby steps?
Why Science Guy (10:32 AM): Precisely -- this is the second major assumption of the Santa Fe group.
Instead of starting with life beginning complex, as it is today, it started as a simple set of chemical reactions.
Then the current complexity was added layer by layer, more or less like the highway system.
This is in contrast to the RNA view, where you start with a fair amount of complexity appearing by chance.
Another problem I have with the RNA world comes from debating "Intelligent Design" and Creationist types.
It's really hard to distinguish a random, unexplainable event from a miracle.
Dave on Earth (10:33 AM): Right.
So if we don't need a freak accident (or miracle as you say) with creating RNA, could we be looking at a universe teeming with life at almost every corner and not know it?
You mentioned that Mars doesn't have too much prospect, but Europa is different.
Why Science Guy (10:35 AM): Life may well be common, provided there are Earth-like planets orbiting in the habitable zone of the right type of stars.
Whether that life evolves into intelligence (or even multicellularity) is another question.
Honestly, I hope that's rare -- I don't want to meet any Klingons out there!
Dave on Earth (10:36 AM): Me either. An aggressive alien race, they are.
Not that we're any different!
Why Science Guy (10:37 AM): I'm not sure I'd want to meet us, either!
About Mars and Europa:
I am what is called a "carbon chauvinist" -- I think life has to be based on carbon, mainly because of simple chemistry.
That means you need liquid water for a long time.
Well, Mars lost its oceans early on. So if life started there it's probably long gone by now.
Europa has tidally heated oceans under a mile of ice, so there could be life down there...
You've probably heard that there are plans to poke around Europa on NASA's drawing boards.
We have a similar situation (google Lake Vostok) in the Antarctic, so the technology is available on Earth.
Dave on Earth (10:38 AM): Do you think we'll ever be able to peer underneath Europa's icy shell and know for certain?
...or would you even want to know?
There are some purists out there who'd rather us leave that world untouched (a little nod to Arthur C. Clarke's works here, of course).
Why Science Guy (10:40 AM): If there is life on Europa, we're probably talking about microbes or stuff like what's around our deep sea vents.
No little green men!
Dave on Earth (10:41 AM): Let's say there is microscopic life within Europa.
Do you think it'd resemble microbes here on Earth (returning to the inevitability aspect)?
Why Science Guy (10:42 AM): As I said above, it would probably be carbon-based.
That means that there has to be something such as DNA that carries the information to run the chemical reactions.
Whether it would have to be DNA? That is a to-be-determined question.
I wouldn't be surprised either way.
Dave on Earth (10:43 AM): Brings me to one of my last questions...
It sounds like you wouldn't be shocked if we found alien life right in our solar system's back yard, so to speak.
What about the rest of humanity -- are we too fixated on being an exclusive pocket of life to imagine that it's inevitable there are other life forms out there?
Why Science Guy (10:48 AM): Actually, I would be a little surprised if we found life in your own "back yard," although it would be a tremendous discovery.
If by the "rest of humanity" you mean educated people in the developed world, I doubt if flying saucers landing on the White House lawn would stay in the headlines more than a couple of weeks.
We're used to the idea of life out there.
My problem is usually to convince my students that it requires some special conditions.
Dave on Earth (10:48 AM): ...and not a miracle, correct?
Why Science Guy (10:48 AM): Definitely not a miracle. Just ordinary chemistry and physics.
As far as intelligent, technological life?
I subscribe to the Enrico Fermi argument:
If they were really out there, they'd be here already.
Does this get us into UFOs now?
Dave on Earth (10:49 AM): I think Discovery Space has explored UFOs plenty :)
We have this nice opinion piece up about UFOs already.
At any rate, thanks so much for chatting!
Why Science Guy (10:51 AM): You're welcome -- this has been fun!
Article posted May 5, 2009.
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