Six mind-blowing ideas
Posted: Monday, April 06, 2009 10:06 AM by Alan Boyle
NASA / JPL / SSI
An infrared view from the Cassini orbiter reveals the Saturnian
moon Titan's surface. Could Titan harbor life as we don't know it?
|
Is "life as we don't know it" closer than we think? Are microbes behind the world's biggest extinctions? Is most of our morality bound up in hidden "dark morals"? Blow your mind with six flights of scientific fancy from the Origins Symposium, presented by Arizona State University.
The weekend forum, organized to inaugurate ASU's Origins Initiative, focused on the beginnings of life, the universe and everything - including consciousness and culture. Among the luminaries in attendance were biologist Richard Dawkins, neuroscientist Steven Pinker, anthropologist Donald Johanson and a basketball team's worth of Nobel laureates. (On Saturday I almost got lost as I wandered around The Boulders resort with two of the nicest Nobelists you ever did meet, Frank Wilczek and John Mather.)
Physicist Stephen Hawking sent his regrets, due to a chest infection that put him in the hospital in California - but he also sent an audiovisual presentation that will be played at tonight's conference-closer. (Hawking went through a similar medical episode more than three years ago.)
Some of the weekend's presentations delved into the science world's best-known unknowns: What will we find at the Large Hadron Collider? What's the nature of dark energy and dark matter? How does consciousness arise? The experts also discussed some lesser-known unknowns that were no less intriguing.
During the conference sessions, I sent out enough Twitter tweets to confound a canary, but for those who weren't able to follow along in real time, here are six of my favorite mind-blowers:
Weird life under our nose?
Paul Davies, a physicist and astrobiologist based at ASU, says we've been so busy looking for life as we know it that we may be missing out on life as we don't know it. That's what he calls "weird life." Organisms that rely on metabolic processes other than the usual DNA-plus-protein routine may be dwelling "under our noses, or even in our noses," Davies says.
But it's more likely that weird life would be found in conditions that are inimical to life as we know it, living in isolated pockets of Earth's biosphere. Weird life could conceivably lurk far beneath Earth's surface, feeding off the energy and chemicals available deep below. Some of the chemicals essential for weird life may even be poisonous to our kind of life. For example, arsenic could play the role that phosphorus plays in our own metabolism.
What about silicon-based life? We probably wouldn't see that on Earth, but we could conceivably see it on Titan, one of Saturn's moons. That's according to Peter Ward, a biologist and paleontologist at the University of Washington. Titan's environment could allow for the existence of long-chain, silicon-based molecules known as silanes, analogous to carbon-based molecules on Earth. Might there be silicon-based life on Titan? Oh, if only Arthur C. Clarke were still alive!
Did the moon make us possible?
The current mainstream scientific view is that the moon came into existence 4.6 billion years ago as the result of a cosmic collision between Earth and a Mars-size planet gone wild (which is known in the literature as Theia). What impact did that catastrophe have on Earth's development?
Computer simulations show that the moon's presence has slowed down Earth's rotation rate from a little more than five hours per day to today's 24 hours, and the gradual slowdown is continuing. The moon also helps stabilize the tilt of Earth's axis, moderating what otherwise would be wild swings between summer and winter, Caltech planetary scientist David Stevenson notes.
Did the moon make Earth more hospitable for life? Stevenson says life probably would have developed in any case, but the moon's effects certainly have made things more pleasant for organisms like us. Another intriguing fact is that the apparent size of the moon and the sun are nearly identical as seen from Earth - and that may have helped spark our distant ancestors' interest in astronomy. Cue the "2001" music again, folks.
Life interrupted on Mars?
What about life on the Red Planet? There's ample evidence that liquid water flowed, trickled and pooled up on Mars billions of years ago, but scientists are still debating whether that would have been enough to allow for the development of life.
ASU planetary scientist Phil Christensen, who has been playing key roles on NASA's Mars Odyssey mission as well as the Mars rover missions, says the geological effects seen to date could have been created by liquid water over a time span of hundreds or thousands of years rather than millions of years. He theorizes that cosmic impacts could have sporadically melted huge volumes of ice in the Martian crust, creating flash floods and temporarily thickening up the planet's atmosphere.
Is it possible for life to develop from primordial soup in just 100 or 1,000 years? That's the big question that Christensen would like the astrobiologists to answer. In the meantime, he's thinking of ways for future Mars probes to nail down whether the liquid water lasted a long time, or was merely a flash in the pan.
Greenhouse extinctions
It's pretty well accepted that a cosmic impact, involving a monster asteroid or comet, set off the extinction event that led to the dinosaurs' demise 65 million years ago. But what about the other extinctions - including the world's biggest die-off, which occurred about 250 million years ago? In a recently published book as well as another soon-to-be-published book, Ward suggests that marauding microbes are among the prime suspects.
He calls this idea the "Medea hypothesis" - a moniker that mirrors James Lovelock's Gaia hypothesis and evokes the mother from Greek mythology who killed her own children. "Life is rather like Medea - a very nasty mother, not a good mother," Ward says.
One "Medea" scenario involves a rapid rise in carbon dioxide, usually from volcanic eruptions. That sets off a greenhouse effect, which reduces ocean circulation, which leads to oxygen-deprived dead zones, which encourage the rise of sulfur-reducing bacteria, which belch up hydrogen sulfide, which kills off species in the sea and on land.
The idea has been rather controversial, but it's worth thinking about - what with CO2 levels on the rise and hydrogen sulfide belching up off the coast of Namibia.
Humanity's mind-blowing rise
Donald Johanson, the paleoanthropologist who discovered the famous "Lucy" hominid fossil 35 years ago, cited some thought-provoking statistics about humanity's rise: Ten thousand years ago, the whole of humanity and our domesticated animals accounted for just 0.1 percent of Earth's total mammalian biomass. Today, that figure is 98 percent.
That demonstrates just how much the future of life on Earth has come under our control. Our survival was a close thing, however. ASU's Curtis Marean says genetic analysis indicates that the human species went through a bottleneck about 140,000 years ago, which reduced our ancestral population to as few as 600 individuals. (This time frame will ring a bell with "Battlestar Galactica" fans.)
Marean surmises that the 600 may have survived a climatic downturn at that time by congregating around the beaches of southern Africa and adding seafood to their diet. (The full research appears in the journal Nature.)
If humans had stuck to small-group hunting and gathering, our population would have hit a global equilibrium level of about 70 million, ASU anthropologist Kim Hill says. But because of the rise of agriculture and urban societies, the human population passed the 6-billion mark a decade ago, with more than 70 million added every year. For what it's worth, Hill observes that the number of known human occupations has surpassed the number of the world's known mammalian species (almost 7,000 vs. 5,400).
Dark morality
University of Virginia psychologist Jonathan Haidt blows my mind with his theory of dark morality - which is a social-science parallel to dark energy and dark matter. When it comes to morals, everyone agrees that we should whenever possible avoid harming people and provide care for the needy. The same goes for issues of fairness and reciprocity ("Do unto others...") Haidt calls these "visible morals," analogous to the 4 percent of the universe that we can see.
But those represent just the tip of the iceberg: Most of the mechanics of morality have to do with three "dark morals": in-group loyalty, respect for authority, and issues of purity and sanctity. This is what accounts for qualities such as patriotism, conformism and taboos about food and sex. (Haidt drew a laugh when he noted that conservatives tend to focus on sex, while "liberals are getting increasingly concerned with food.")
Haidt's online research, conducted through YourMorals.org, indicates that liberals put a high value on morality having to do with harm and care, fairness and reciprocity - but not on the dark morals. The more conservative you are, the likelier you are to value all five moral dimensions roughly equally, as shown in the graph accompanying this blog posting from Ethan Zuckerman.
Conservatives might be on the smarter track, at least if you size up things the way Charles Darwin did more than a century ago. In Chapter 5 of "The Descent of Man," Darwin delves deeply into the role of morality in natural selection:
"... When two tribes of primeval man, living in the same country, came into competition, if (other circumstances being equal) the one tribe included a great number of courageous, sympathetic and faithful members, who were always ready to warn each other of danger, to aid and defend each other, this tribe would succeed better and conquer the other."
"The kind of morality Darwin is talking about here is dark morality," Haidt said.
For still more mind-blowing ideas, tune in to today's Webcast of the Origins Symposium's public sessions.
Update for 1:50 a.m. ET April 7: I've revised the reference to Darwin's views to remove the implication that Haidt himself specifically said conservatives were on the right track. Haidt only implied that the kinds of moral values that Darwin cited in "The Descent of Man" included the kinds of values given more weight by conservatives than by liberals.
