≡ Menu

The Stars and the Odds

The universe so frequently sends the message that we humans are not entirely special. In fact, the notion of us as ‘privileged observers’ seemed to be dead as recently as a few years ago. Over the centuries we had learned that the Sun did not revolve around us, nor was the Sun itself the center of the cosmos, and with the understanding of its true position in a galaxy of stars, Sol became just another G-type star circled by planets. The recent ‘rare Earth’ hypothesis does challenge the idea that our planet is of a kind likely to be found elsewhere, but exoplanet discoveries will soon tell us whether or not Earth-like worlds really are common.

We may be getting used to the idea of Earth as just one of the vast billions of planets that are doubtless sprinkled through the Milky Way, but we have a long way to go in terms of our thinking about the future. For the one place where that sense of privilege seems to remain is in the idea that having achieved our planetary dominance, we are simply here to stay. The history of our planet tells a different story. Mass extinctions aren’t pretty, and new work at the University of Bristol makes the case that recovering from them can take tens of millions of years.

Three periods of extinctions occurred in the boundary between the Permian and Triassic periods some 251 million years ago, a series of ecological mega-disasters that some believe was driven by volcanism. In any case, the so-called ‘Siberian Traps’ coincide with this boundary, covering a vast area of Siberia in basaltic lava in a period of volcanic activity lasting for a million years. Ninety percent of life on the Earth disappeared, and recovery was agonizingly slow.

Sarda Sahney and Michael Benton (both at Bristol) have been studying the recovery of tetrapods, animals with a backbone and four legs. While life itself rebounded quickly after the disaster, their research shows that specialized animals involved in complex ecosystems took much longer to recover. From the paper:

Though globally tetrapods recovered quickly, the dramatic restructuring that occurred at the community level was not permanent and communities did not recover numerically or ecologically in the Early and Middle Triassic. It would not be until the great diversity of the Late Triassic, which included dinosaurs, pterosaurs, crocodilians, rauisuchids, aetosaurs, rhynchosaurs, trilophosaurs, sphenodonts, amphibians and mammals, some 30 Myr after the end-Permian event, that terrestrial tetrapod community diversity was restored.

Lycaenops, a victim of the extinction

Life’s essential resilience is unquestionable, but so is the fragile nature of any specific ecological niche. The end of the Permian saw extinctions so wide-ranging that the survival of any particular species hung by a thread.

Image: The sabre-toothed Lycaenops was a top predator of the latest Permian in South Africa. Lycaenops was a gorgonopsian, one of a group of highly successful animals that dominated faunas in the Late Permian, but were wiped out, together with 90 per cent of all species, by the end-Permian mass extinction. Credit: Mike Benton, University of Bristol

A tenet of Centauri Dreams from the beginning has been that we humans must expand into the cosmos if we expect our species to survive. The Earth may never again undergo volcanism like that associated with the Permian/Triassic boundary, and perhaps the next asteroid strike won’t occur for another million years. Perhaps. Individuals might choose to play such odds, but a technological culture at the brink of expansion into its planetary system cannot. Long-term, even a relatively settled and middle-aged solar system like ours is rife with potential danger.

Unprivileged as we seem to be, let’s push into nearby space as a hedge against planetary catastrophe, a species-wide insurance policy. And if we do continue to expand, we may well wind up as Freeman Dyson has so often speculated, evolving in our own separate ways according to the ecosystems we move into. That sense of a viable future no matter how we change along the way should drive us to look at all our options, both near the Earth and gradually outward as we expand into the Orion Arm.

The paper is Sahney and Benton, “Recovery from the most profound mass extinction of all time,” in Proceedings of the Royal Society B, published online January 15, 2008 (abstract).

Comments on this entry are closed.

  • tacitus January 22, 2008, 11:10

    I wholeheartedly agree with the sentiments of the post. Assuming that disaster doesn’t befall us in the couple of hundred years, it’s likely that humanity will look back on this time as the brief moment when we were aware of our vulnerabilities but not yet capable of doing much about them.

    As it is, and given enough warning, we already have the technology to avert or handle some of the disasters that could befall us, short of a real civilization ending event. We will cope with global warming, even if it causes immense misery along the way, and should we discover an asteroid on a collision course with Earth, we have a good chance of deflecting it given enough time.

    In 200 years we should be all but immune to asteroids and comets and our knowledge of the sun and geological forces should be advanced enough to clearly understand the risks and pitfalls that might be in the offing. (Just think back 200 years and what we didn’t know then!). So at some point in the not too distant future, we will know with much more certainty than today what the risks are and, of course, ways to avoid them. Then perhaps one day we will have to make the decision to head for the stars (assuming we do find a solar system as habitable as this one) in order to preserve the future for the human race.

  • Starfleet commander January 22, 2008, 13:46

    This is funny because I’m currently on a long forum thread about this same subject. Or at least on the idea of the “measurement problem” in QM, biogenic tuned universe etc…

    I think more and more evidence is coming to light which indicates that biology and “observers” are very important to the universe if not essential.

    Anyways I didnt want to drag this into a philosophical conversation as Im sure that not meant to be the point of the post.

    My view is that if we werent supposed to travel in space and colonise our neighborhood then nature would not have provided the laws and capability in order for it to happen. And to waste that priviledge would indeed be mind-boggling.

  • ljk January 22, 2008, 14:12

    Galileo supposedly said something similar to the Inquisition
    when they were trying to get him to denounce such crazy
    ideas as that Earth and the other worlds go around the Sun,
    that if we weren’t supposed to know such things, why then
    did God endow us with the ability to question and reason?

  • Heather January 22, 2008, 16:07

    I just finished reading Gorgon by Peter Ward, so finding this post through the folks at Universe Today was timely! Figuring out where we’ve been is a good way to assess where we’re going. From my reading, it appears that there were several things that got the great Permian extinction under way. The critters who survived seemingly did so because they were good at living in an oxygen-poor environment. We’ll just go ahead and take that to the next step with some further space exploration/colonization!

  • Ronald January 22, 2008, 17:52

    Yes, with Tacitus, I also agree that survival of humankind and human civilization are one of the strongest arguments for colonization of the Milky Way (beside the more philosophical arguments).

    I am not so sure though that in due time we will be able to counter all threats: incominf planetoids OK, but how about super volcanoes and a new ice age?

  • Administrator January 22, 2008, 18:04

    Ronald, indeed, volcanism may be the kind of thing we can’t control. I would imagine asteroid deflection technologies will be worked out long before we have any ability to control such natural phenomena, which makes that move at least into nearby space something we should not delay unnecessarily.

  • Jim Baerg January 22, 2008, 23:13

    & natural disasters aren’t the only problem. How many ways are there to trash your civilization & what are the odds of tripping over one of them in any given time period. Nuclear war & environmental pollution are 2 risks we are aware of now. Could there be others we might no see until it’s too late.

    Having lots of people living off earth means there are more likely to be survivors of any really bad mistake, who will then know one more thing not to do.

  • Hank Roberts January 23, 2008, 0:55
  • Gerhard von Müehle January 23, 2008, 6:49

    Upon impact, the larger pieces of Shoemaker-Levy blew fireballs thousands of kilometers high into Jupiter’s atmosphere…When Fragment G collided with the King of Planets two days after the first impact, the flash was so bright that infrared scopes all over Earth were momentarily fried. The scar left by Fragment G was larger than Earth itself, and the explosive energy released was the equivalent of a Hiroshima-sized nuclear bomb exploding every second for 13 years.

    Tom Bissell

    ‘Tis time New hopes should animate the world, New light should dawn from new revealings To a race weighed down so long…

    Robert Browning

    Too soon from the cave too far from the stars. We must ignore the whispers from the cave which say, “stay.” We must listen to the stars that say “come”

    Ray Bradbury

    The impulse to push further, to live longer, to journey farther, and to leave messages for those who follow us, when we inevitably falter and fall, these will perhaps be our most enduring features.

    Gregory Benford

    Saving the Earth and enlivening the universe are not questions of engineering, or physics, or even economics; they are matters of will power. We have the power. Now we must find the will.

    Marshall Savage

    Let Man Burst Forth, With Fire In His Light, And Spread Himself, Into The Far-Flung Night!

    von Müehle

  • ljk January 23, 2008, 8:29

    “All civilizations become either spacefaring or extinct.” – Carl Sagan

    Another answer to the Fermi Paradox.

  • george scaglione January 23, 2008, 9:23

    ljk,yes but,gulp,that means that alot must become extinct! sometimes i see how easily that could happen to us also!!! but on the other hand this very afternoon a soacecraft might arrive from the other side of the galaxy! who knows? had a friend once who would have answered when i said something like that…”from your mouth to gods ear!!” thanks very much, george

  • Edg Duveyoung January 23, 2008, 11:40

    Good news: we’re already succeeded!

    (Prepare for a sermon. Cut me a break. Live on my side of the fence for a few paragraphs.)

    With all our talk about humans transforming into “other creatures” that “fit” new ecosystems or, even, nesting inside AI machines, I ponder often what it is that we think we are preserving when each new “embodiment of mind” that moves us father from our original “home:” the human brain.

    At sixty-three years of age, I know about attrition.

    I know how my mind has changed over the decades and how many “usefulness-outlived toys” I long ago left on the cluttered floor of my history — careers, skill sets, passions, fads, educational degrees, friends, religions, dogmas, ideals, morals — every time I examine myself, I find a “constantly evolving into other forms of being” me. Fifty six years ago, for a few days, a Schwinn bike was my whole reason for getting out of bed.

    Whoever arrives on distant orbs will have notions we cannot resonate with, and in all probability they will not have any deeper grasp than we do about what the “next step” for civilization should be, though they may have a long list of “could be’s.”

    There is a way to ENTIRELY pierce this uncertainty about the future of us.

    To see our history of literally emerging from a chemical soup and finally devising a brain that can begin to comprehend a universe so vast, I doubt if anyone here thinks that humanity is the only intelligent life in the cosmos — surely the “intelligence” that’s behind the impulse to organize matter into ever more complex states (local decrease in entropy) is as potent a force in nature as the second law of thermodynamics.

    Since we are so comfortable with becoming engineered organisms or robots, why not just IDENTIFY with life in general? After all, humanity is thought to be moving into, what?, thousands of other kinds of “operational modalities,” and soonish enough, the varieties of “vehicles of thought” will be so expansive as to constitute numerous distinct species — or, well, life!!!!

    This is something everyone can do: dwell upon the concept of “pure life” being our deepest nature and that somewhere somewhen there will be a “form of us” evolving and pushing AWARENESS into the cosmos. To hold one’s breath and only want our present “meat robots” to be the “future us,” is a myopic parochial chauvinism — yet it is sinless to adore being what we are in particular — that’s cool, eh?

    Folks, we ARE that very “wave front of awareness.”

    We can be found thinking that we are the tippy top top of bestest mostest awareness as it is expressed here on earth, but miss not that everything ELSE is as pristinely AWARE as we. While we are, ahem, the preferred embodiment of that awareness that we wish to preserve, it is equally true that that awareness is found in the least creature — even bacterium are now known to communicate with chemicals they emit. Indeed, where ISN’T awareness found? Every religion holds this to be true: awareness is the basis of existence — for example, Christ says that the rocks themselves would cry out if He were to stop preaching the truth. Even the rocks!!!

    I know. I know. You’ve never met a talking rock. Don’t miss the concept in the bath water. Awareness is the primal identity — what car I drive, what clothes I wear, whatever “today’s ideas” are that flood my mind, these things will change, but the basic “awareness principle” will not. This is a principle already active throughout the entirety of existence.

    We already are on the most distant planet, and “they” will know that we are “over here” too.

    When I look into the dark, I know my eyes are not able to resolve it into the faint dots of light it contains; my meat bot’s camera lens just cannot “cut it,” but teleologically I know that what I call “I” is already cooking up spicy dishes for itself to consume in every dark corner-that-is-not-actually-dark. Somewhere there is a virus in pure glee as it finds a host, elsewhere a germ pogosticks with delight to find its preferred carbon source, or a whole planet’s Gaia has found a way to become, with each species being a “tissue,” an immense brain/mind/telescope/knower. What matters it to us if the talking-dog only wants to discuss bones recently dug up, or if a copper molecule snuggles up (migrates) to another copper molecule as like-attracts-like in an alloy. A bird of a feather knows another and resonance and attraction and communication and companionship is assured.

    This is LIFE: recognition of “other as self,” and it is already seen in the first moments after the big bang as the laws of nature, the very laws of nature! discover “themselves” and form tribes of distinct species of particles until a short time later there it is evolved enough to find itself having expanded to exploding stars that pepper everywhere with manifestations of PRIMAL AWARENESS. Then, suddenly, spontaneously forming amino acids in space clouds, planets that absorb their star’s radiance (love?,) and BLAM, wiggly thingies in the mud….a blink later, some guy is flagging down a taxi while texting about the latest fine essay by our beloved Paul Gilster.

    Can you feel the distance of time and vastness of space and the fecundity of materiality supporting your very next thought? Though you might want to describe it differently than I just did, you are exactly just that “next way of being” that infinite recursivity has devised.

    We are soaring throughout the stars right now. The “us” that’s peering into the light-filled darkness can only and always find another us already peering back.

    Let the volcanoes cover the Earth with red oceans of death and black shrouds of ash — nyah nyah nyah, can’t touch us!

    I will never be a star quarterback, but I have been Bret Favre.

    You will never be a giant throbbing planetary brain, but you’ve been one in many of your sci-fi readings.

    We will never set foot on Mars, but we are Oppy right now absorbing the sedimentation layers of Vicky like a nun loving her next rosary bead.

    I’m everywhere right now finding every you.

    Every biologist studying knows the presence of self staring back up from the petri dish.

    The physicist precisely knows how strongly a nucleus wants to be itself instead of an expansive wave form and delights at this in particular and at the majesty of laws of nature mystically arising from virtuality in general.

    So, who’s still reading this essay?


    I’m the you that cared enough to go this far into these words.

    Thanks to everyone here for being the me that didn’t have time to go where you all are right now. I love it that you’re elsewhere.

    Basking in plenitude here.


  • andy January 23, 2008, 13:38

    I’m going to disagree with Sagan here: There’s no reason why becoming spacefaring means you get to cheat extinction. It just means the probability of various possible ways to become extinct change, perhaps in favour of a longer time until ultimate extinction.

    “All civilisations become extinct. Some become spacefaring first.”

  • dad2059 January 23, 2008, 13:50

    Unfortunately, I know a great many people who’s take is “we should take care of the Earth we have” and “if human beings can’t take care of their nest, why should we spread our wastefulness into the Cosmos?”

    Many of these people would rather see us go extinct than to colonize space.

    Thanks Paul for reminding me that these people are wrong.

  • george scaglione January 23, 2008, 15:22

    heather…way to go!! so rarely do i see a female poster i had to write,right away to encourage you to keep on sharing your ideas!!! and, andy,yes going into space is not a sure way to cheat extinction but i’m sure it can help! also…dad,yes we surely must NOT go into space just to behave like children as we have all to often on earth! respectfully one and all george

  • ljk January 23, 2008, 15:58

    Carl Sagan’s phrase would not have been nearly as
    effective/mind grabbing if he had included caveats in
    his sentence, just as no one would remember Patrick
    Henry’s famous declaration if he said “Give me liberty
    or give me death, unless of course we can meet somewhere
    in the middle on this so no one gets really hurt or offended.”

    Maybe no civilixation/being will live forever, maybe not.
    Forever is a long time from now, so we just don’t know yet.

    If an advanced society can find a way to survive the ultimate
    demise of this Universe, that’s virtually immortality as far as
    I am concerned.

  • Hans Bausewein January 23, 2008, 16:32

    Maybe they mean that it is better to go extinct than to go on to destroying all habitable places in the universe.

  • ljk January 23, 2008, 17:23

    What the folks advocating extinction of the human race
    rather than spreading our so-called destructive tendencies
    to the stars are assuming we will be the same creatures
    that we are now by the time we do head off into the galaxy.

    More than likely this will not be the case.

    Of course I wonder how they would feel knowing that
    entire star systems are wiped out ever day all over the
    Universe by supernovae and black holes.

    And we probably shouldn’t mention that one day the
    Sol system and other systems may be turned into Dyson
    Shell for maximum efficiency of collecting solar energy
    and maximizing land area.

    As for Sagan’s quote, if we try to continue existing in
    our current state of civilization, we will eventually run
    out of resources and room if we stay on one planet.
    By then our civilization will have collapsed, so that as
    far as the rest of the galaxy is concerned, we will have
    vanished off the map.

    Is this what has happened to other societies that did not
    learn in time? We need to find out. And we can only do
    that by getting off this planet.

  • Ronald January 24, 2008, 19:07

    @andy: I usually agree with andy, except this time;

    I am not so sure that extinction (of a civilization) is inevitable.

    I would define civilizational immortality for practical purposes as a civilization that is able to exist beyond the lifespan of its star or the habitable stage of its planet.

    To achieve this longevity I think there are two general phases: the first is to learn to live sustainably on one and the same planet, not depleting nor polluting its vital resources. The next phase is expansion. At first I thought that they were alternative ways toward longevity, but I realize now that both are prerequisites: expansion of an inherently sustainable civilization.

    Civilizations are by nature expansionist, and yet they have come and gone, perishing because they were not sustainable (for various reasons, not just resources, but resources have often been crucial). Apparently, if a civilization is not sustainable in itself, expansion alone will not save it.

  • andy January 25, 2008, 8:57

    @Ronald: I disagree with your definition of immortality, if only because (to take a rather contrived counterexample) if a civilisation sticks around on its home planet then decides to move en masse in one monster generation ship to another planet when its homeworld’s climate gets too toasty, and the ship blows up, they’ve gone extinct but still qualify as immortal…

    Immortality with an expiry date is not immortality in my book. I’d demand a refund :)

  • Ronald January 25, 2008, 20:33

    I was referring to civilizational immortality, not personal, physical immortality.

    In that sense, yes, if the civilization is able to outlive its planet and/or star, it is practically immortal (even if its world accidentally blows up around).

  • Ronald January 25, 2008, 20:39

    Having said that, I realize I was a bit too hasty with the last part: if the entire world blows up on a civilization (or its world/generation ship), then obviously it was not so immortal after all, a bit clumsy to put all your eggs in one basket anyway. In that sense, I agree with you.
    However, I still think that immortality (or at least longevity and survival) of a civilization is not the same as that of an individual. The latter is clearly not required for the former.

  • ljk February 24, 2008, 0:33

    The Day the Seas Died

    The “Great Dying” at the end of the Permian period, some 250 million years ago, was the most catastrophic of the five mass extinctions in Earth’s fossil record. More than half of the families of living things died out, and as many as 95 percent of the planet’s marine species were lost. At the same time, perhaps 70 percent of the land’s reptile, amphibian, insect, and plant families became extinct.

    This mass-extinction event may hold clues to current global carbon-cycle changes, according to Jonathan Payne, assistant professor of geological and environmental sciences at Stanford University.

    Full article here:


  • ljk April 30, 2008, 23:52


    How Life on Earth Nearly Ended 250 Million Years Ago

    Douglas H. Erwin

    To read the entire book description or the introduction, please visit:


    Some 250 million years ago, the earth suffered the greatest biological crisis in its history. Around 95% of all living species died out–a global catastrophe far greater than the dinosaurs’ demise 65 million years ago. How this happened remains a mystery. But there are many competing theories. Some blame huge volcanic eruptions that covered an area as large as the continental United States; others argue for sudden changes in ocean levels and chemistry, including burps of methane gas; and still others cite the impact of an extraterrestrial object, similar to what caused the dinosaurs’ extinction. Extinction is a paleontological mystery story. Here, the world’s foremost authority on the subject provides a fascinating overview of the evidence for and against a whole host of hypotheses concerning this cataclysmic event that unfolded at the end of the Permian.