But how can we best understand these numbers and reinterpretations?
Attempting to comprehend the unimaginably long stretch of time that preceded the present is something many scientists must confront. This usually poses incredible challenges because our minds have evolved to conceptualize time on scales of years, decades, and centuries; as opposed to time on scales of millions or billions of years. In fact, even conceptualizing the timescales of human civilization is quite daunting. For example, Ancient Egyptian civilization lasted from 3,000 B.C.E. to 332 B.C.E., which for context is 13 times longer than independent United States history.
Evolutionary biologist and paleontologist Stephen J. Gould dedicated his life to understand phenomenon on deep time scales. He stated that:
The human mind may not have evolved enough to be able to comprehend deep time. It may only be able to measure it. An abstract, intellectual understanding of deep time comes easily enough, getting it into the gut is quite another matter.
I understand (and respect) Gould’s opinion on this issue, but I slightly disagree. I do not think that an abstract, intellectual understanding of deep time comes easily. When I was in college I spent hours thinking hard about deep time. In order to improve my understanding of phenomena on these time scales I frequently relied on metaphor and varying time scale comparisons. I also read books about the history of the universe that detailed events in reverse chronology. I felt as though reverse chronology accounts of our past eased me gently into ever greater time scales. Once I had absorbed an understanding of phenomena that occurred on scales of millennia, it was far easier for me to absorb an understanding of phenomena that occurred on scales of hundreds of millennia. After applying this approach, it became progressively easier to view all events in our contemporary world from the perspective of cosmic time.
Applying this approach also helps to understand studies that alter the master narrative of existence like the two papers mentioned above. How should we approach an understanding of the new human-chimpanzee-bonobo divergence time and the new age of our universe? I would argue that for proper context we should consult one of the most important intellectual tools humans have developed to understand deep time: the Cosmic Calendar.
Astronomer Carl Sagan popularized the Cosmic Calendar in the 1980s. This calendar is used to map the entire lifetime of the universe, and all significant events, onto a single calendar year. By employing this calendar metaphor, the human mind is able to approach un-human time scales in a human format.
For the recalculated human-chimpanzee-bonobo divergence time we must now conceptualize a gradual split that occurred over a scale of 7 million years (14-7mya), as opposed to a relatively sudden split 6 mya. A speciation occurring over 7 million years is almost an unfathomably long period of time. Once modern humans had left Africa it took them ~50,000 years to colonize nearly every available landmass on the planet. That means the human-chimpanzee-bonobo speciation event took 140 times longer than human colonization of the entire planet!
On the Cosmic Calendar our previous understanding of the human-chimpanzee-bonobo speciation event occurred on December 31st at approximately 20:04 P.M. So with this framework the critical split leading to the evolution of humans occurred about 4 hours before the New Year! Under our new interpretation we can still imagine the split as occurring on December 31st. However, the key difference is that the split will be occurring over several hours: from 15:24-19:04 P.M. So the human emergence story is now occupying a slightly larger fraction of the famous Cosmic Calendar.
But let’s remember to put this in proper perspective. Biological evolution, and speciation specifically, can take millions of years. For the human mind this is nearly impossible to understand without a useful tool like a Cosmic Calendar. As I stated above, the speciation event between humans and our closest relatives took 140 times longer than the complete colonization of the planet. Yet we still only emerge on the last day of the universe’s time scale. Our distant hominid ancestors made it just in time for the New Year’s Party.
The universe’s age was also recalculated last week. For many people this may not mean very much. What is the difference between 13.77 and 13.82? This may seem like an inconsequential age extension of a universe we already knew was ancient. But let’s remember that 13.77 BILLION to 13.82 BILLION (~50 million years) is the difference between primates and no primates. Almost all of primate evolution, and certainly all-significant events within primate evolution, occurred within the last 50 million years! Approximately 50 million years ago, lemurs had yet to raft to Madagascar, New World Monkeys had yet to make their mysterious journey to South America, and apes did not exist at all!
The reason I discussed time scales related to great ape evolution (e.g., hundreds of thousands of years and millions of years) first was to ease you back into the world of billions. On the Cosmic Calendar the reimagining of a universe 50 million years older does not change very much: our galaxy still forms around the same time, as does our planet, and life, and all other significant developments in the history of our universe. This is because on the scale of the universe, 50 million years is comparable to a couple of months for a human. The equivalent of adding all of primate evolution to the Cosmic Calendar is inconsequential to the unimaginable expanse of cosmic time.
Why is this important to understand? Apart from being mind-bendingly cool and being a useful tool to help you understand scientific discoveries; it should also help you put your own life in context. Our entire order’s evolution is nothing on the temporal scale of billions of years. Our species emergence is but a preamble to the universe’s New Year’s Eve party. And modern civilization? We arrived a few seconds (13 seconds to be fair), before the ball dropped. When we start to discuss an individual’s life, we may be diving into the temporal scales of nanoseconds.
If you regularly read this blog, you already know that I believe adaptive evolutionary processes explain system order in the universe. There does appear to be a unity between how systems evolve (whether they be chemical, biological, cultural, technological, etc.). In this sense, selection-like processes generate order in the natural world that many cultural groups assumed was intelligently designed. But can selection be extended to explain the universe itself?
Before humans knew that there were other planets in the universe, many people believed that Earth could only be explained by intelligent design (e.g., God). However, we now know that the Earth's existence can be explained by probability. There are likely way more than sextillion planets in the observable universe, so it is not necessarily surprising that one suitable for complex life exists. In fact, it would not be surprising if billions of planets suitable for complex life existed just within our own galaxy.
But people who make the God-of-the-gaps argument never really go away. Now that it is intellectually bankrupt to argue Earth (or life, or our star, or our solar system, or our galaxy) was intelligently designed, many turn to the universe itself. As physicists have pointed out, our universe is well-designed for the emergence of intelligent life (although not that well-designed).
Therefore, it is the job of 21st century science to uncover the mysteries as to why our universe appears to have the physical constants it does. At the moment, the theory is far ahead of the empirical evidence (unlike the situation in evolutionary biology). A dominant theory proposed to explain our universe's physical constants is Cosmic Natural Selection (CNS). This theory, first explored by physicist Lee Smolin suggests that:
black holes may be mechanisms of universe reproduction within the multiverse, an extended cosmological environment in which universes grow, die, and reproduce. Rather than a “dead” singularity at the centre of blackholes, a point where energy and space go to extremely high densities, what occurs in Smolin's theory is a “bounce” that produces a new universe with parameters stochastically different from the parent universe. Smolin theorizes that these descendant universes will be likely to have similar fundamental physical parameters to the parent universe (such as the fine structure constant, the proton to electron mass ratio, and others) but that these parameters, and perhaps to some degree the laws that derive from them, will be slightly altered in some stochastic fashion during the replication process. Each universe therefore potentially gives rise to as many new universes as it has black holes.
The analogy with how selection operates in biological systems is impossible to miss. Given that this is how complexity is generated by other natural systems, it seems logical that this could be the case of our universe (within the multiverse). In fact, a study published this month in the journal Complexity posits that Smolin's CNS theory would mathematically be in concordance with the production of universe's increasingly likely to produce black holes (and therefore universe's conducive to complex life).
Let that sink in. If Smolin's theory is true, our universe exists the way it does because of a cosmic natural selection between universe's within a multiverse of universes with different physical laws.
But all theories need empirical evidence. There is currently no evidence for the existence of either a multiverse or successive generations of universes that transmit their fundamental constants. And it's possible we won't have that evidence in the near future (or ever).
Either way, I'm optimistic. Advances in physics theory are likely to further support the idea of a multiverse and the CNS. And I wouldn't bet against CNS being lifted from theoretical obscurity. The idea has a certain Copernican principle to it. Just as scientific inquiry revealed that our planet, solar system, and galaxy were not particularly special, it seems increasingly likely that scientific inquiry will do the same for our universe as well.
The question has been raised because various independent groups have been sending purposefully directed high-intensity messages intended for extraterrestrial intelligences (ETI), or METI's.
The authors of this study made two conclusions regarding METI:
1) The benefits of radio communication on Earth today outweigh any benefits or harms that could arise from contact with ETI
2) Current METI efforts are weak, mostly symbolic, and harmless
But are the answers to independent groups sending messages into the cosmos really that simple? I mean I think it is fairly obvious that we should continue improving our communication abilities. We have no evidence to support the idea that there are intelligent civilizations in our galactic neighbourhood, much less evidence to support the idea that there is an ETI civilization that poses danger to our existence. However, expanding Earth's radiosphere and directly sending messages into the cosmos are two very different things. For example, SETI astronomer Seth Shostak has claimed that, due to decreasing signal strength our radiosphere is not detectable beyond five light years. In contrast, purposefully directed, high-intensity messages significantly increase Earth's detectability beyond the radiosphere.
Essentially, this is the reason SETI pioneer Philip Morrison believed that we, “the newest children” in the cosmos, should be passive and just listen for a long time. We should not 'shout at the cosmos'. We should not explicitly make our presence known before we know the types of intelligence that may exist.
This is a very complex issue. What should we do moving forward? Should we be engaged in an active search for ETI? Or should we be passive?
For me personally, I mostly agree with astrophysicist and science fiction author David Brin. He supports the International Academy of Astronautics Second Protocol for dealing with Transmissions from Planet Earth. This protocol states that:
all of those controlling radio telescopes forebear from significantly increasing Earth's visibility with deliberate skyward emanations, until their plans were first discussed before open and widely accepted international fora.
To me, this seems like a reasonable position. If we are to purposefully send a METI, that message should be first discussed by an international panel of experts in astronomy, physics, biology, anthropology, history, and politics. And the message should be collectively sent as a message from Earth and by Earth; not from an independent collective. As David Brin stated, no one should feel free to:
broadcast from Earth, whatever, whenever, and however they want.
On the other hand, there are those who would prefer to completely ban METI's; I disagree with that stance. Don't get me wrong, I see wisdom in the perspective that we should remain silent, passively listening to the cosmos for thousands of years, before sending messages into a cosmic environment we are just beginning to understand. However, I feel as though we should send controlled and well thought out messages from our species and planet for two main reasons:
1) If there are highly advanced civilizations in the Milky Way, they would know we are here by studying the physical and chemical patterns of our planet, regardless of our radiosphere.
2) I believe it to be probable that any civilization with the capability of traveling to another solar system would not do so with the intention of eradicating life and high intelligence.
The first point is simple, not controversial, and easily explained: a sufficiently advanced civilization could easily detect the presence of our civilization by analyzing the spectrum of reflected ultraviolet, optical, and near-infrared sunlight for our planet's surface. They could also, perhaps more easily, become cognizant of our existence from artificial nighttime lighting and the unusual chemical composition of our planet due to the excessive burning of fossil fuels.
The second point is far more complex, certainly controversial, and not easily explained. Biologists have often warned that contact between species that evolved in different ecosystems often leads to one species going extinct. Likewise, historians have argued that “first contact” between more advanced and less advanced civilizations have often led to disastrous inter-human relations (e.g., slavery, colonialism, civilization collapse, etc.). From this reasoning, they often conclude that if we make our presence known to a vastly more advanced civilization than our own, we are placing own existence in extreme peril.
However, consider the following: as our species has become more knowledgable and technologically advanced, we have also moved strongly in the direction of compassion, altruism, and the inclusion of all within the protection of law. I believe that this is directly tied to satiation. As we create a world of abundance; a world with drastically reduced levels of hunger and poverty, we elevate our cultural ideals. David Brin referred to this as:
an abstract sympathy, unleashed by full bellies and brains that are capable of seeing enlightened self interest in the long term survival of the world.
Natural selection is the driving force for the creation of our biosphere. It may be that natural selection is the driving force for all biological evolutionary processes in the universe. Natural selection permits populations to evolve via differential survival rates. And although we are a very young species, we are already close to releasing our species from this process. In essence, natural selection is permitted to operate because of resource scarcity. But as we continue to raise the standard of living for our species as a whole, we accelerate ourselves into a world where we all live long enough to reproduce. Differential survival rates will no longer drive our evolution. As a result, we also accelerate ourselves towards a world free of the byproducts of resource scarcity (i.e., extinction, war, slavery, etc).
When we create science fiction work depicting human-alien conflict, we are projecting biological system conflict produced from a world governed by natural selection. But the interaction between two highly advanced technologically-based systems will not likely be governed by that type of system conflict. A new, more intelligently directed form of evolutionary change should take the place of natural selection. Surely, any species with the capability of visiting our planet would have long ago released themselves from the biological tyranny of the process that created them.
As many scientists have pointed out, including theoretical physicist Paul Davies, biological intelligence is likely to be a fleeting phase in the evolution of the universe. If this is the case, it stands to reason that any civilization able to receive our messages and visit our planet would undoubtedly be post-biological. This essentially means they would be post-singularity. And a post-singularity species has not only lifted itself from a world governed by differential survival, but has also lifted itself from finite sentience and death. Therefore, I would not expect conflicts produced by the mechanism of natural selection to dominate an encounter between us and an advanced space faring civilization.
At least, that is my reasoning, and it is why I fully support a controlled, globally agreed upon form of METI. I think the benefits of discovering extraterrestrial intelligence and making “first contact” would outweigh the risks.
That being said, I am sure many would disagree with me. Perhaps it is foolish of me to assume that all advanced intelligent species would have lifted themselves from natural selection and tend towards extraterrestrial altruism. But that is why we must have open dialogue about METI. We can't tolerate random independent groups to send messages without first consulting the global community. If we send messages we must be prudent. And, from my perspective, prudence would be making sure that any message is sent from Earth and by Earth. No one should be allowed to send whatever messages they want, whenever and however they want.
For anyone who studies evolution, it is important to realize that there are characteristic evolutionary patterns. For example, evolution tends towards greater complexity (although not always). Evolution also has a variable speed (which is often contingent on the environment). And a study recently published in PNAS indicates that evolutionary processes generally select for species-level living systems with universal size distribution. Science Daily summarized the importance of this universal size distribution well:
Flocks of birds, schools of fish, and groups of any other living organisms might have a mathematical function in common [… researchers] showed that for each species studied, body sizes were distributed according to the same mathematical expression, where the only unknown is the average size of the species in an ecosystem.
For the researchers of this study, these apparent universal size distribution may be useful for understanding how systems of living matter operate. However, this study made me think of the role of size in evolutionary processes. Specifically, what causes different living systems to evolve different sizes? And what living system has evolved the largest overall size?
The role of size in evolutionary processes has always been a contentious issue for evolutionary theorists. Central to the issue of size has been the idea that natural selection tends to drive the evolution of larger and larger overall size, regardless of whether the living system is a bacterium, a hydra, or a chimp. This observed trend has been labeled Cope's rule after Edward Cope, a 19th century paleontologist who first proposed the trend. The late evolutionary theorist Stephen J. Gould disregarded Cope's rule as a “psychological artifact”, however recent studies have provided empirical evidence to support the general pattern.
Paleontologist Joel Kingsolver supports the idea that evolution tends to favour large body size, stating that:
In 80 percent of the studies, there's consistent selection favouring larger size.
Disappointingly, the theory to explain this pattern is still underdeveloped. In fact, Kingsolver contends that there may not be any universal driver of larger body size:
My guess is that it's a mix of particular reasons for particular speices. You may be able to make through lean times better than someone who's smaller. Females that are larger are able to produce more eggs. If males are competing for females, larger size is often favoured.
The evolutionary driving forces behind the evolution of truly huge body size are not clear, and likely differed from one group to the next.
Although evolutionary theory explaining the drive behind selection for larger body is underdeveloped, we do have a better idea of proximate determinants of body size. For example, many theorists have demonstrated that mode of locomotion and reproduction are both important factors either constraining or enabling large body size.
As Brian Switek discussed at length recently, the monstrous sauropod infraorder was able to “sidestep” the costs and risks that constrain mammalian size by “externalizing birth and development.” The size distribution of sauropods dwarfed the size distribution of all other known terrestrial organisms to ever exist.
So of these supermassive sauropods, what species holds the title of largest? The answer to this question was far more difficult to find than I originally thought. Michael Stevens from VSaucerecently claimed that Giraffatitan was the largest known “with certainty of a complete skeleton”. Estimates of Giraffatitan come from one skeletal sample, and was thought to be 72-74 feet in length and weigh ~30-40 tons. Compare that to the largest known African elephant which weighed ~12 tons.
However, there is general consensus in the paleontological community that there were larger sauropods than Giraffatitan. Thankfully, I had some help from Brian Switek to better understand the contemporary debate:
According to Switek Argentinosaurus and Supersaurus
are the leading contenders for heavyweights in the dinosaur world. The longest known of these giants was a Supersaurus that is estimated to be 108-111 feet long. The heaviest was a Argentinosaurus estimated to have weighed 73 tons. They were the giants of the gigantic sauropoda order.
But we can't forget about a living clade of animals that has experienced an explosive increase in size distribution: cetaceans. The largest (by far) of our mammalian cousins is the blue whale. And the blue whale is not just a contender for largest living animal, they are also contenders for largest animal of all time. In fact, in terms of absolute weight, it doesn't appear to be close at all. Whereas Argentinosaurus weighed 73 tons, the largest known blue whale weighed over 200 tons! More than double the weight of the largest known dinosaur! But to be fair, blue whales don't have to worry as much about the crushing weight of Earth's gravity. The battle is much closer when we compare length: Supersaurus was between 108-111 feet and the largest known blue whale was ~110 feet.
Blue whale Balaenoptera musculus = heaviest of all time?
The SV-POW paleontology blogger team made a brilliant point that we should suspect that Supersaurus was on average longer than blue whales because we are comparing with biased sample sizes:
A huge sample of blue whales included none longer than 110 feet, while our comparatively pathetic sample of sauropods has already turned in one animal (Supersaurus) that may have just edged that out, and another (*A. fragillimus*) that - assuming it was really as big as we think - blows it out of the water.
In case you were wondering, A. fragillimus is estimated to have been between 130-200 feet long! It completely blows my mind that a terrestrial organism can reach those sizes on our planet (just imagine how big sauropods would have been if they had evolved on planet the size of Mars!).
The red image represents A. fragillimus, potentially the longest organism ever
In case you were wondering, no primate species has ever been a contender for largest living system. The primate order is comparatively small, with the largest contemporary species (gorillas) weighing between 300-400 lbs (or about 0.15-0.2 tons!). Even if we consider extinct species, no primate has ever even been a contender for largest land mammal. The largest, Gigantopithecus, weighed approximately 1,200 lbs (or about 0.6 tons). Of course, I think Gigantopithecus is aptly named (and I think sympatric populations of Homo erectus would agree); but they are only aptly named in comparison to our relatively puny order. Primate size has probably always been constrained by underdeveloped quadrupedalism and selection for long-term infant dependence.
Reconstruction of Homo erectus and Gigantopithecus in Southeast Asia
However, it is interesting to know that all species body sizes (from prokaryotes to sauropods) are distributed according to a potentially universal power law. This universal describes how ecology influences average species size, while genetics contains variability around that average. In the future, I'll be interested to see whether evolutionary theorists can better describe the adaptive pressures selecting for larger size. It is useful to have a grasp on the proximate causes of body size, but the ultimate causes will be necessary to better describe how living systems develop over time.
The latest research, and for some the most exciting, was the discovery of Kepler-62e. Kepler-62e is a planet located approximately 1,200 light years away from Earth in the Kepler-62 star system. This system is composed of a smaller and cooler star than our Sun, and is accompanied by five known planets, two of which are rocky worlds in the stars habitable zone.
From the limited data available to astronomers at this point in the detection process, Kepler-62e has been touted as the “most Earth-like” planet known to date. In fact, by utilizing the Earth Similarity Index (ESI) equation Kepler-62e scores a 0.82 (scale: 0-1.0). That score matches the unconfirmed exoplanet candidate Gliese 581 g (Figure 1).
Figure 1 - Current Potential Habitable Exoplanets
ESI is calculated using data on the mean radius, bulk density, escape velocity, and surface temperature of an exoplanet. In the popular science media a high ESI (~0.80-1.00) is code for “Earth-sized planet within the habitable zone.” In essence that is what everyone means when they say “Earth-like.” But a growing number of scientists, myself included, are beginning to realize that we are getting way ahead of ourselves. At the moment we have no way of understanding an exoplanet's geophysical history, present state, or the dynamics of the entire star system. Astronomer Phil Plaitrecently tempered enthusiasm re: Kepler-62e by stating there are too many unknowns to call it Earth-like yet:
Kepler-62e could have a thick CO2-laden blanket of air, making its surface temperature completely uninhabitable, like Venus. Or it might not. We just don't know yet, and won't for quite some time.
In short, more data on Kepler-62e could radically alter its ESI number from 0.82 to 0.44! And that is not even factoring in data on how a radically different solar system would affect Kepler-62e's development and present state.
This frequent, and perhaps cavalier, use of the term “Earth-like” has caused some astronomers concern. Astrobiologist Caleb Scharf recently forced us to consider what is meant by “Earth-like” when used in the context of exoplanet discovery:
Utterance of [Earth-like] can evoke all sorts of images. It may make us think of oceans, beaches, mountains, deserts, forests, fluffy clouds, fluffy bunnies, warm summers, snowy winters, the local pub, or the fabulous hubbub of the local souk. But this is typically far from the meaning attached by scientists. It can simply indicate a planet with a rocky surface, rather than a world with a thick gaseous envelope. It can mean a world that is roughly the same mass and density as Earth. It can mean a planet orbiting a star like the Sun. Or it can just mean that we got bored of saying things like 'a two-Earth mass object in a close to a circular orbit around a roughly 4 billion year old main-sequence star that is similar in mass to the Sun'.
For me, Scharf adequately articulates the complexity in this galactic search. He also reminds me that we still must be humbled by what we can't know at this point in time. Our estimates on the number of Earth-like worlds are going to be in constant flux this century because our data will be imperfect. All we need to do is remind ourselves of Earth's history to know our current data are insufficient to label an exoplanet “Earth-like”. Despite the fact that our planet's orbit and size have been relatively static, it has gone through phases (and will go through future phases) that we would consider inhospitable.
On a final note, we must also remember that our planet has the current temperature, chemical composition, and general climate it does because of the biosphere. Life, as far as we know, creates an “Earth-like” world. So perhaps, moving forward, the term “Earth-like” should be reserved for planets that we can tell are operating in a Gaia-like way. By that I mean that we should only call a planet Earth-like if the light elements (e.g., carbon, nitrogen, sulphur, and nitrogen) are being dominated and controlled by biology.
As I have stated before, fewer potential civilization-ending natural disasters exist today when compared to our evolutionary past. For example, before we emerged from sub-Saharan Africa 100,000 years ago, an earthquake, tsunami, volcano, famine, or even animal competition could have ended the human experiment. Today, those risks may be locally disruptive, but they do not threaten collective human existence.
But we must remember that there are rare natural events that should still be considered major threats: asteroids and supervolcanoes. Our species has never had to deal with a major encounter with an asteroid, but surprisingly, we have some experience with supervolcanoes. Consequently, by studying how supervolcanoes have affected our species in the past, we may be able to gain a better understanding of their likely impact in the future.
Lake Ilopango EruptionLocation of Lake Ilopango (Southeast of San Salvador) in relation to Classic Maya Civilization
Recently, I interviewed University of Texas paleoecologist Dr. Robert Dull to discuss supervolcanoes. Dr. Dull studies climate change on millennial scales of time and has recently discovered evidence that a major volcanic eruption occurred around 536 C.E. at Lake Ilopango in modern day El Salvador. According to Dull, the Lake Ilopango eruption significantly affected Mayan civilization during the Classic Period and represents the likely culprit of extreme global weather events in 536-537 C.E.
From Dull's initial research, the 6th century volcanic eruption in El Salvador approached VEI 7 status. The pyroclastic flow from a blast of this magnitude would have destroyed an area 2,000 square km in size. Dull conservatively estimates from the population density of this area during the 6th century that this eruption would have directly killed 40,000-80,000 individuals.
But the effects of the Lake Ilopango eruption go far beyond the initial blast. Although more research is necessary, Dull reveals that a lot changed after 536 C.E.:
Some people lost out and some benefitted. Some cities flourish after this event. All cities were covered in ash, but some had only about 1 cm of ash. I believe that there must have been refugee movement to largely unaffected cities in the north.
It will be interesting to see what future research reveals about how Maya society changed after 536. However, Dull believes this eruption affected more than just local Mesoamerican stability. It may have also caused nearly two years of extreme weather throughout the Northern Hemisphere.
The extreme weather events of 536-537 C.E. is one of the largest historical and paleoecological mysteries. Throughout Eurasia several written records chronicle the events:
The sun became dark and its darkness lasted for one and a half years… Each day it shone for about four hours and still this light was only a feeble shadow…the fruits did not ripen and the wine tasted like sour grapes.
— Michael the Syrian
For the sun gave forth its light without brightness, like the moon, during this whole year, and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear nor such as it is accustomed to shed.
— Procopius
…the sun began to be darkened by day and the moon by night, while ocean was tumultuous with spray, from the 24th of March in this year till the 24th of June in the following year… and the following winter in Mesopotamia was so bad from the large and unwonted quantity of snow the birds perished.
— Unknown Syrian
So we have had a winter without storms, spring without mildness, summer without heat.
— Cassiodorus
If the sun becomes dim because the air is dense from rising moisture—as happened in [536/537] for nearly a whole year…so that produce was destroyed because of the bad time—it predicts heavy trouble in Europe.
— John Lydos
Dendrochronological records from Eurasia and South America also show slow growth during these years, which indicates poor growing seasons.
Dull believes that the 18 months of Northern Hemisphere darkness was caused by a global dust vale ejected from Lake Ilopango. If true, this would be the second time in the last 2,000 years that a volcanic eruption prevented summer. Dull notes that:
The Indonesian Tambora eruption in 1815 is the best analogue to Ilopango. They were eruptions that shook the world and produced similar effects. In the case of Tambora it caused a year without summer. In the case of Ilopango it caused the years without summer.
Can this tell us anything about the future?
Perhaps the most frightening aspect of supervolcanic eruptions are their inevitability. If our species plans on sticking it out long-term on planet Earth, we will encounter a supervolcanic eruption. Both Ilopango and Tambora were technically VEI-7 eruptions (or close to VEI-7 eruptions). In the short-term, their impact was locally devastating and globally disruptive. However, neither significantly threatened the existence of our species. Would a VEI-8 eruption be that much worse?
Category 7 eruptions eject about 100 cubic kilometers of volcanic ash. Category 8 eruptions eject 1000+ cubic kilometers of volcanic ash. This difference is significant. Whereas category 7 eruptions have devastating short-term impacts on local and global climate, category 8 eruptions pose serious long-term challenges.
Lake Toba Eruption
Surprisingly, modern humans have encountered a VEI-8 eruption before. Approximately 74,000 years ago Lake Toba in Indonesia erupted and ejected 2,800 cubic kilometers of volcanic ash. This eruption blanketed South-east Asia, South Asia, and the Arabian Peninsula in ash. Recent studies indicate that it also led to prolonged cooling and deforestation throughout Asia.
Consequently, many evolutionary theorists have posited that the Lake Toba eruption could have had profound effects on our emergence as a species. Genetic evidence suggests that our species suffered a severe genetic bottleneck sometime before 60,000 years ago. Our population may have dropped to as low as 1,000 breeding pairs. Although more research needs to confirm the hypothesis, the Lake Toba supereruption was the likely cause of the bottleneck. At the very least this eruption slowed our expansion into East Asia and Australia.
By a fluke of geography, we evaded extinction. Had the eruption occurred in East Africa, we may not have been so lucky. What if it happened today?
Supervolcanoes Today
From my perspective I am not sure whether a VEI-8 would threaten our species with extinction, but I am sure that it would seriously destabilize our global infrastructure.
As we have learned from Dull's research at Lake Ilopango, “some people lost out and some benefitted” in Mesoamerica after 536 C.E. Would we expect the same if a VEI-8 volcano erupted at say, Yellowstone National Park? Certainly all of North America would be negatively impacted if the Yellowstone Caldera erupted with comparable intensity to previous eruptions. As a result would we see North American refugees heading to whatever European, South American, African, or Asian country would have them?
Yellowstone Eruption Radius
There are too many hypothetical situations to know for sure. However, it is conceivable that what occurred locally in Mesoamerica in 536 C.E. could repeat itself globally if we encountered a VEI-8 in the near future.
During our interview, Dull acknowledged that a VEI-8 eruption would be “horrific.” He added that:
We can’t predict [supervolcanic eruptions]. There are known supervolcanoes that have repeatedly erupted. Yellowstone 3 times in the last 2 million years. That is something to be concerned about. We know it has erupted in geologic history in a devastating way.
We may not be able to predict supervolcanic eruptions, but a recent study published in the journal Nature indicates that there are characteristic processes that occur decades (perhaps even a century) before a major eruption. If volcanologists can gain a better understanding of these pre-eruption processes, we may be able to detect the next supereruption decades before the event. This would at least give us time to prepare (possibly avert?) disaster.
Currently NASA leads a program to categorize all “potentially hazardous objects” (PHO) (e.g., asteroids and comets). Of course, this program is extremely important for the future stability of our civilization and planet. But why are we not preparing in the same way for supervolcanic eruptions? We already know that eruptions on the scale of Lake Toba 74,000 years ago happen with much higher frequency than asteroid impacts. Yet we have no plan to deal with VEI-8 eruptions. Even the Long Now Foundation, an organization focused on promoting a 10,000 year framework to build our global civilization has no official stance or plan for dealing with a VEI-8 eruption.
So what should we do? I would argue that our current knowledge of past supervolcanic eruption events indicate that they pose a significant risk to global stability. I also feel that it would be enormously irresponsible if our species did not develop a program analogous to the NASA PHO effort. So here is what I propose we must do:
We must gain as much data and knowledge of past supervolcanic eruptions as possible.
We must attempt to understand whether supervolcanic eruptions occur in any recognizable pattern on geologic time scales so that we can roughly estimate when we should expect the next major eruption.
We must fund volcanology research into better understanding the processes that occur decades (and even centuries) before a major eruption.
And we must start to hypothesize about technology and/or methods that could be used to prevent supervolcanic eruptions.
As Dr. Dull's research shows us, eruptions at or near the scale of VEI-7 have the ability to destabilize civilizations and create years without summer. Research by other paleoecologists have shown us that supervolcanic eruptions happen with surprising regularity on scales of thousands of years. Therefore it would be prudent to prepare for such events.
Finally, I would like to add that I am not trying to be an alarmist. I am sometimes accused of being overly optimistic about our future as a species. But I believe all evidence indicates that our species has tremendous potential and the possibility for a very bright future. However, if we would like to create a healthy and stable global civilization, we must properly prepare ourselves for natural events that occur on larger time scales than we are accustomed to thinking about.
If we invest in more research, take the necessary precautions, and develop the right technology, we can knock another natural disaster off of the list of events that threaten the human experiment.
Anthropology is a subject that has attracted its fair share of anti-intellectual theorists before. These anti-intellectuals are scientists from other areas of scientific inquiry that attempt to propose their own theories about who we are and where we came from despite having no formal anthropological training. Consequently, these people are usually a massive headache because they have no idea what they are talking about. Dr. Jonathan Marks did a great job elucidating why anthropology may attract this type of anti-intellectualism in a recent podcast I did with him.
Either way, I woke up yesterday to an infuriating article published in the Guardian: Big brains, no fur, sinuses… are these clues to our ancestors' lives as 'aquatic apes'? The article gave an international platform to several scientists that support the Aquatic Ape Hypothesis/Theory (AAH/T). This hypothesis proposes that there was a, as yet unidentified, aquatic phase of human evolution causing our ancestors to develop bipedalism, big brains, subcutaneous fat, sinuses, and lack of fur. Supporters of the AAH believe that these features are all indicative of an ancestral past spent living primarily in deep creeks, river banks, and the sea.
But there is one major problem: there is no evidence to support it. No evidence is usually a problem in science. No ancestral hominids have ever been found that lived in an aquatic environment.
The theory was first developed in 1960 by Sir Alister Hardy. Since then its supporters have generally been from biology. The AAH has received little to no serious consideration from the anthropological community. And nor should it. Paleontologist Chris Stringer accurately acknowledged in the Guardian article that:
[T]he whole aquatic ape package includes attributes that appeared at very different times in our evolution. If they were all the result of our lives in watery environments, we would have to have spent millions of years there and there is no evidence for this - not to mention crocodiles and other creatures would made the water a very dangerous place.
These are all very important points. If the AAH is valid we would have spent millions of years in a watery environment and we should suspect all features of the “aquatic ape package” to have evolved together, not at separate times. But this is not what paleoanthropology has taught us about our past. We know that our hominid ancestors lived primarily in woodlands 6 million years ago, and primarily in savanna landscapes 3 million years ago. Furthermore, two of the most important features that the AAH attempts to explain, bipedalism and encephalization, developed millions of years apart from each other.
Certainly it makes sense that hominids would develop new anatomies to adapt to such an alien [aquatic] environment. But once those hominids returned to land, forsaking their aquatic homeland, the same features that were adaptive in the water would now be maladaptive on land. What would prevent those hominids from reverting to the features of their land-based ancestors, as well as nearly every other medium-sized land mammal? More than simple phylogenetic inertia is required to explain this, since the very reasons that the aquatic ape theory rejects the savanna model would apply to the descendants of the aquatic apes when they moved to the savanna. […] It leaves the Aquatic Ape Theory explaining nothing whatsoever about the evolution of the hominids. This is why professional anthropologists reject the theory.
And yet anti-intellectuals still get a credible platform to spout nonsense about our aquatic past. Perhaps I could contain my disappointment if it all remained academic. However, ecologist Dr. Michael Crawford claims that our brain growth was solely because our aquatic ancestors had a diet rich in Docosahexaenoic acid (DHA), which is found in seafood. So he then makes the dangerous (and ridiculous) argument that:
[W]ithout a high DHA diet from seafood we could not have developed our big brains. We got smart from eating fish and living in water. More to the point, we now face a world in which sources of DHA - our fish stocks - are threatened. That has crucial consequences for our species. Without plentiful DHA, we face a future of increased mental illness and intellectual deterioration. We need to face up to that urgently. That is the real lesson of the aquatic ape theory.
Using an unsupported theory of human encephalization to claim that lack of fish in someone's diet will lead to mental illness and intellectual deterioration is just anti-intellectual pseudoscience. Considering how far evolutionary theory has progressed in the past few decades, it is disappointing to see these scientists employ it so poorly. The Aquatic Ape Hypothesis is nothing more than an unsupported adaptive story. It has not been supported by evidence, and I find it highly unlikely that it ever will be.
In 2009, John Hawks thought the AAH fit the description of pseudoscience. In 2013, it still fits the description. We have never been aquatic apes.
The coelacanth is the oldest living species of lobe-finned fish. In fact, it is so old that it has acquired the nickname “living fossil.” The distinction is probably more an artifact of the history of science than of the coelacanth's ancientness. In the early 20th century scientists believed that the coelacanth went extinct 70 million years ago (15 million years before the K-T mass extinction!). So when a live specimen was discovered off the coast of South Africa it came as a major shock. Upon first analyzing the fish, South African chemistry professor JLB Smith famously wrote the cable:
MOST IMPORTANT PRESERVE SKELETON AND GILLS = FISH DESCRIBED
Since the discovery scientists have been perplexed by this Lazarus taxon. How has the coelacanth managed to persevere over the past 300 million years without changing at all?
This question really gets at the heart of a bigger evolutionary conundrum: does evolution have a uniform speed? Or is the speed of evolutionary change intrinsically variable?
Evolutionary theory pioneer Stephen J. Gould was one of the first to propose that evolutionary change varied tremendously. In order to explain this change he proposed the idea of punctuated equilibrium. This theory proposed that species change is largely contingent on environmental change. Gould recognized that morphological stasis could be correlated with ecological stasis. Therefore, he reasoned that massive ecological changes would prove to be the major drivers of rapid selection over the scale of evolutionary time.
This contradicted dominant theory in the 1970s because all theorists embraced phyletic gradualism: the idea that evolution was steady state with gradual transformations changing lineages. In reality, both punctuated equilibrium and phyletic gradualism are not mutually exclusive. We know now that some species can change quickly (in evolutionary terms) in response to major ecological pressures. However, change can also occur gradually over millions of years in response to more svbtle ecological changes.
This brings us back to the “living fossil”: the coelacanth. Has this species really remained unchanged for nearly 300 million years? Is it really a “living fossil”? If so, its history would be a remarkable example of how an organisms environment can stabilize selection.
A recent study published in Nature finally gave us some insight into this decades-old evolutionary mystery. In this study the first genome sequence for the coelacanth was reported. The data revealed what had been obvious to many, the coelacanth's protein-coding genes are evolving slower than any other known animals. One of the researchers in this study, Kerstin Lindblad-Toh explained that:
We often talk about how species have changed over time, but there are still a few places on Earth where organisms don't have to change, and this is one of them. Coelacanths are very likely specialized to such a specific, non-changing, extreme environment - it is ideally suited to the deep sea just the way it is.“
However, Lindblad-Toh was also quick to emphasize that the term "living fossil” is unscientific and not an accurate representation of a extant species:
It's not a living fossil; it's a living organism, it doesn't live in a time bubble; it lives in our world, which is why it's so fascinating to find out that its genes are evolving more slowly than ours.
Here is where we can highlight an interesting (and extreme) example of just how variable evolutionary change can occur. Our species, Homo sapiens sapiens, have evolved very quickly. Let's put this in comparison by comparing our evolution to our slowly evolving coelacanth cousins. Coelacanth fossils have been found that stretch back to the mid-Paleozoic. This is approximately the time the last supercontinent, Pangaea, first formed. That means the coelacanths emerged 70 million years before the entire Dinosauria clade.
In contrast, our genus, Homo, is approximately 2 million years old. Over this period of time our brain has tripled in size. That is unparalleled evolutionary change. I have written extensively about our genetic origins in the past so I won't repeat myself here. However, I do want to emphasize that one of the drivers of this change has been ecological disequilibrium. Recent studies by several geoscientists have convincingly demonstrated that the East African savanna was characterized by rapid environmental change during a 200,000 year period approximately 2 million years ago. Clayton Magill, a graduate student involved in one of these studies elucidated how these changes could have stimulated punctuated equilibrium-like effects on human brain growth:
Changes in food availability, food type, or the way you get food can trigger evolutionary mechanisms to deal with those changes. The result can be increased brain size and cognition, changes in locomotion and even social changes - how you interact with others in a group. We show that the environment changed dramatically over a short time, and this variability coincides with an important period in our human evolution when the genus Homo was first established and when there was first evidence of tool use.
Since that period environmental change has played a tremendous role in the creation of our species genotype and phenotype. As modern humans exploded throughout the world, we were forced to adapt quickly to previously alien environments. Most of this adaptation was made possible by our unique ability to drive cultural and technological evolution. However, pertinent contemporary phenotypic differences within our species, like skin colour variation, were also caused by biological adaptation to extreme differences in environmental conditions.
Exploring evolutionary change in the coelacanth and humans represent two major biological evolutionary extremes. Both organisms perfectly encapsulate Stephen J. Gould's theory of punctuated equilibrium. Ecological pressure can either strongly stabilize selection or drive rapid changes over relatively short periods of time. However, I do want to emphasize that these are the extremes. For many species, phyletic gradualism is king because ecology will change, but it will change slowly.
And don't forget, today is DNA Day! A time to celebrate the discovery of the molecular backbone of all life on our terraqueous globe! Without the discovery of DNA our knowledge of our own evolutionary past would be relatively impoverished, and this article would not have been possible!
The technological singularity has quickly become one of the most controversial concepts. It represents a theoretical future period in time when superintelligence emerges through technological means. During a recent conference on the future of artificial intelligence (A.I.) futurist Anders Sandberg proposed that this concept has three major commonalities:
accelerating change
prediciton horizon
intelligence explosion
The term was popularized by computer scientist Vernor Vinge in 1993. He recently expounded on the creation of the concept and the reasoning behind it:
the spectacular feature of A.I. was not making something as smart as a human, but creating minds that were more intelligent than humans. That would be a different type of technological advance. That would change the thing that is the top creative element in technological progress, and since it would be beyond human intelligence, there is a certain unknowability about what would happen beyond that point. Therefore, I came up with the metaphor with the singularity as it is used with blackholes in general relativity reflecting this fact that there is not much information you can imagine beyond the point in time when super-human intelligence comes into place.
Several theorists have hypothesized about how the singularity will happen, when it will happen, and how it will change human nature. In 2007, artificial intelligence expert Ben Goertzel published a paper in Artificial Intelligence outlining the main scenarios proposed by futurists thus far. They included everything from a Sysop scenario where a highly powerful benevolent A.I. effectively becomes a “system operator” to a Skynet scenario where A.I. is created, improves itself, and malevolently enslaves or annihilates humanity. I am definitely most closely aligned with the Kurzweilian scenario. I believe that humanity will create advanced A.I. that can create better, more advanced A.I.. However, I also believe we will intimately merge with technology. By the end of this process humanity will essentially be post-biological in nature. I suspect that it will not be an abrupt or particularly chaotic transition. It will happen gradually over the span of decades (in some ways it has already started happening).
Either way, I am writing this post because I would like to start an important discussion on the term “singularity.” Although I have referred to myself as a “singultarian” and count myself as a Kurzweilian-defender, I find the term singularity problematic. As Vinge stated the term singularity is used to suggest unknowability beyond a certain technological event horizon. However, I posit that this “technological event horizon” is not an actual future reality. I believe that there will come a time when humans are no longer the “top creative element of technological progress” but a “singularity” will not happen. What I mean is that if we keep using the term “singularity” it may start to metaphorically resemble the carrot and stick idiom:
If humans start artificially enhancing their own intelligence in the 2030s and developing relationships with advanced A.I., the approaching decades (e.g., 2040s-2050s) currently predicted to play host to the singularity will start to become clearer to us than they currently are (i.e. they will not be a technological singularity).
Vernor Vinge has admitted this much stating that:
If you became one of the supersmart creatures, things would not be any more unintelligible to you than the current world is to un-enhanced humans.
Furthermore, we cannot remain intellectually comfortable with the term singularity if we are starting to make predictions of a post-singularity world. Several futurists, including Ray Kurzweil, have already started proposing probable post-singularity developments. But making these predictions completely contradicts the metaphorical validity of the term. If the singularity metaphor proved useful we should find ourselves facing a literal information blackhole. But I don't think that is what we find ourselves facing.
As a futurist, I feel like we need a new term to better describe what we mean when we say technological singularity. I do not yet know what term would fit best. The term “infinitely self-generating technology” has a nice ring to it. This is a feature of the singularity identified by Mike Rugnetta of PBS Idea Channel. However, I can already think of a host of reasons why that term is problematic.
What do you think? Is the technological singularity a useful concept?
A few days ago, biologists Alexei Sharov and Richard Gordon published a paper that sent shock waves throughout the academic community. In their paper titled Life Before Earth they propose that life originated before the formation of our planet. But just in case that wasn't radical enough, they further state that:
adjustments for potential hyperexponential effects would push the projected origin of life even further back in time, close to the origin of our galaxy and the universe itself.
In my last post I discussed the transition from non-life to life. However, no where in that article did I discuss the timing of that transition. The dominant view at present is that life originated ~3.5 billion years ago. This estimation comes from direct and indirect evidence of prokaryotic (single-cell organism) activity in Western Australia and South Africa. Although it is hard to prove empirically, most biologists are confident that life on Earth did not exist before this period. This is because between 4.6-4.0 billion years ago Earth can best be described as a chaotic hellscape of magma oceans and planetesimal collisions (i.e., not the best place for RNA replication).
But this latest paper by Sharov and Gordon claims life existed before earth (before even the formation of our galaxy). To be precise they calculate the time of origin for life to be 9.7 ± 2.5 billion years ago. For context our galaxy is ~8 billion years old, and our solar system and planet is 4.6 billion years old.
How could this be?
The authors propose that biologists have neglected to acknowledge the “cosmic time scale” of life. In their paper they posit that in terms of genetic complexity life has grown exponentially (they measure genetic complexity by the number of non-redundant functional nucleotides). Prokaryotes, eukaryotes, worms, fish, and mammals were included in the authors study sample and genetic complexity was plotted on a logarithmic scale (Figure 1). With these data they found that genome complexity doubled every 376 million years. They conclude that if genome complexity doubles at this rate prokaryotic complexity could not have been achieved by 3.5 billion years ago. Both Sharov and Gordon blame biologists of presuming a rapid primordial evolution in order to fit the time scales required by our planet's age.
Figure 1
Within this new proposed framework the authors suggest that this exponential doubling time is an inherent evolutionary process accelerating quickly with new, more efficient forms of information storage than genomes (e.g., highly complex brains, language, books, computers, internet). Now I am definitely someone that believes exponential growth is an inherent property of evolutionary processes. I am also someone that thinks evolutionary processes generally tend towards greater and greater levels of system complexity (even though recent research has demonstrated that this is not always the case). However, more than doubling the time of the origin of life proposes a radical re-imagining of life and our universe. Such a proposition demands tremendous evidence. I commend Sharov and Gordon for proposing a bold idea and approaching the evolution of life from a novel perspective, but they did not provide us with tremendous evidence.
Biologist PZ Meyers was first to point out that they cherry picked their data. They did not include many organisms that would have completely thrown off their logarithmic scale. Furthermore, even if the logarithmic scale with all organisms plotted remained unchanged it would not be scientific to assume you can project it back to single nucleotide replicators that existed 9.7 billion years ago. Finally, biologists have only started to understand what is and what is not functional within the human genome. Therefore, we cannot assume that measuring genome complexity based off of our current understanding of functional non-redundant nucleotides is useful.
Unfortunately the claim that life originated 9.7 billion years ago might destroy the credibility of both the paper and the authors. I say unfortunately because within this paper the authors actually make a profound claim that I agree with:
The Drake Equation of guesstimating the number of civilizations in our galaxy may be wrong, as we conclude that intelligent life like us has just begun appearing in our universe. The Drake Equation is a steady state model, and we may be at the beginning of a pulse of civilization. Emergence of civilizations is a non-ergodic process, and some parameters of the equation are therefore time-dependent.
A) Our universe was not always well-suited for the evolution of life
B) Biological evolution requires billions of years of planetary stability
C) Biological evolution can produce trillions of species without ever selecting for high-intelligence and civilization
There are actually many more reasons why I think this is likely so I suggest reading my entry Intelligent Life in the Milky Way if you want to know more about it. Either way, my line of reasoning is certainly in line with Sharov and Gordon's assertion that “intelligent life like us has just begun to appear in the universe.” Although they come at it from a slightly different perspective, I obviously find this assertion profound and compelling.
In the end I think Life Before Earth is worth a read if you are interested in learning more about Sharov and Gordon's claims; but I am personally not sold. Biologists may never know the precise historic pathway of inanimate to animate matter and the specific materials present on the prebiotic earth, but I still think a 3.5 billion year origin for life is more likely than a 9.7 billion origin.
In the future biologists do need to demonstrate how biological evolution was able to produce highly complex prokaryotic genomes in a relatively short period of time. There could be a number of currently unknown reasons for this that do not require a single-nucleotide replicator with pre-galactic origins.
That is not to say that life could not have originated completely or partially from space. The idea that asteroids with complex organic compounds seeded our planet during the late-heavy bombardment 4 billion years ago is quite possible. But positing the chemical compounds necessary for life existed 9.7 billion years ago requires more evidence than a logarithmic scale with cherry picked data points.
