July 28, 2017

Review: Five Billion Years of Solitude by Lee Billings

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Where did we come from as a species, and where is the party headed? What’s the expiration date for life on Earth, and just how common — or rare — are we? Those are the big questions in modern day science. This week’s review tackles the latest thinking concerning all of these weighty subjects and more. Five Billion Years of Solitude: The Search for Life Among the Stars by science journalist Lee Billings is a fascinating look at the state of the field. We’re talking astrobiology and the search for extraterrestrial life and intelligence, a truly interdisciplinary endeavor that encompasses all of modern science from physics and astronomy to biology and psychology. [Read more...]

Review: Rare Earth by Peter Ward & David Brownlee.

A controversial classic!

It is perhaps one of the greatest scientific questions of our time. How common are we? Is our existence here in time and space a widespread occurrence in the cosmos, or are we so unique that we are effectively alone? The topic of this week’s review represents a landmark paradigm shift and is an often quoted book that I’ve always wanted to get around to reading and reviewing. Rare Earth: Why Complex Life is Uncommon in the Universe by David Ward & Peter Brownlee posits that animal life in general and intelligence such as our own in particular is a rare, perhaps a singular event in our corner of the galaxy. Published in 2000, its interesting to see how the science of the day stacks up to current thinking. For example, in 2000 a handful of exoplanets were known; almost all were “hot Jupiters,” and the prospects for terrestrial planets looked slim. To date, 779 extra-solar planets have been discovered using a variety of methods, providing researchers with enough data to classify and characterize various types of planetary systems.

It should be noted that the authors do point out that while animal life may be a tough hurdle, simple bacterial life may be common in the cosmos. Our own story lends some credence to this supposition; once conditions in the early history of life on Earth stabilized about 3.5 billion years ago, simple life arose readily. For almost 90% of the span of life on Earth, however, life remained at the simple one-celled stage. It seems that at least in our own case, going to complex multi-celled life was the hard part; but yet in less than a billion years, the explosion of plant and animal life led to dogs, cats, humans, Ipads, etc. How common this tale is remains to be seen. Certainly, the discovery of bacterial life past or present within our own solar system may lend weight to the first half of the Rare Earth hypothesis.
Among the factors that the authors site as conducive to life as we know it;

-An orbit around a single relatively stable star that maintains a steady output for many billions of years, long enough for life to develop;

-A stable orbit within the habitable zone of said star, a place where water can exist in liquid state;

-Condensation from a proto-solar nebula with a high “metallicity” (remember, to an astronomer, the universe is hydrogen, helium, & metal!) full of lots of great but scarce raw materials such as carbon, silicon, nitrogen, etc.

-A single large Moon that acts to stabilize the tilt of the Earth;

-A large “goal tending” planet like Jupiter that deflects a good portion of the life extinguishing comets that come our way.

-A stable position in the galactic habitable zone, not too close to the radiation-riddled core and not in the outer metal poor ‘burbs. A good distance from any life extinguishing supernovae or gamma-ray bursters helps too, a sort of “may you live in mediocre times” curse/blessing.

-Active tectonic plates allowing for subduction and sequestration via a rock and carbon cycle.

To this end, the authors add some interesting twists to the famous Drake Equation, allowing for the events that brought us here in the mix. Certainly, if some of the scenarios such as the formation of our Moon are mandatory, chances for life are slim. One only has to look at the caveats offered by our neighboring worlds of Venus and Mars to see how different the Earth could be.

Still, a nagging hunch pulls at the back of our brain as we read Rare Earth… just how viable is a statistic of one? Are all of these happy accidents mandatory, or can life, once it’s started, make due even under drastically different conditions? One could also point out that these conditions aren’t exactly stable or permanent; the tilt of the Earth’s axis does vary, the output of the Sun is increasing and fluctuates with time, etc. It would be great to have a better understanding of the minimum and maximum criterion for life as it relates to these events. Carbon is probably crucial; no other element forms such long complex chains, although silicon is sometimes also cited as a possible alternative. Water also makes a great ‘universal solvent…” but might oxygen be poisonous to some forms of life? Would we recognize life drastically different from us if we saw it? I’m reminded of Arthur C. Clarke’s Report on Planet Three, where a Martian scientist gives a long and convincing discussion on why life on a hostile planet such as Earth couldn’t be possible.

Read Rare Earth as a very timely and still largely pertinent discussion on one of the biggest questions of our time. I would also recommend James Kasting’s How to Build a Habitable Planet as a great look at how the Earth came to be. Either conclusion has stunning implications; of course, most of us root for sentience and a cosmos teeming with diverse life with Klingons and Vulcans bickering about treaties in a Galactic Federation… but if we are truly  ”it” in our tiny niche of time and space, doesn’t that make us and the Earth all that much more precious and unique, a jewel worth safeguarding and preserving?

17.10.09: Pondering the Possible Fate of the Earth.


Colossus-The Forbin Project: a Sci-Fi classic that kicked off the talks!

What’s the future of humanity and life on Earth? Will we have a good multi-billion year run until our Sun swells into a red giant boiling away our atmosphere, or will we first do the job of snuffing ourselves out? Earlier this year, some of the leading thinkers of our time gathered near Harvard University at the Arrow Theater to discuss just these weighty concepts. Dubbed Crossroads: The Future of Human Life in the Universe, each talk in the series was 30 minutes long and solicited an avalanche of enthusiastic questions. Some of the highlights:

-Gerrit Verschuur discussed the Drake equation and just how prevalent any interstellar neighbors might be; at a guesstimated 2,500 light years, we may be pretty, well, spaced out!

-Maira Zuber discussed the future of space travel in the solar system and the difficulties of overcoming probably the biggest engineering problem; prolonged radiation exposure.

-Astronomers Dimitar Sasselov, David Charbonneau, and paleontologist Peter Ward of Rare Earth fame discussed the slew of recent exoplanet findings and the quest for the true coin of the realm; Earth-like worlds around other stars. Most interestingly, the idea was proposed that a “super-Earth” may be more conducive to the development of life, and our own planet may represent the bottom rung of habitability; indeed, as Ward notes, “Rare does not mean unique!” Another interesting proposal by Ward is what he termed the Medea Hypothesis, a sort of anti-Gaia Hypothesis, were the Earthly biosphere may actually occasionally become detrimental to life, and thus fuel mass extinctions. The name comes from perhaps the worst Mom in mythological history!

-Finally, big time elder thinker Freeman Dyson of Princeton urges that our very search methods for life might be flawed, and that we should be looking for “what is detectable, rather than only whats probable.” he also proposed missions targeting such possible abodes for life such as Europa, the icy large moon of Jupiter.

Whatever the future of humanity is, one gets the impression from the visionary speakers presented that it is NOT endless consumerism. The message in the history of life on Earth is clear; evolve or die. No one will save us but ourselves, and the future is collectively ours to choose!