Nick Nielsen thinks big, as his previous work in these pages and elsewhere has shown. His presentation on “The Large Scale Structure of Spacefaring Civilization” at the 2012 100YSS conference examined humanity’s growth as defined and enabled by the structure of spacetime itself. His continuing work with Heath Rezabek weighs the factors that threaten a technological civilization, while considering what we can do in response. An author and contributing analyst with strategic consulting firm Wikistrat, Nielsen here looks at our concepts of time and the emergence of ‘Big History,’ which might be called ‘history in a cosmic context.’ We are now developing the tools that, used properly, can address and resolve issues of existential risk.

by J. N. Nielsen


James Hutton is often credited with the origins of the modern conception of geological time, which is sometimes called “deep time.” Looking upon the Bass Rock in the outer part of the Firth of Forth James Hutton is said to have remarked, “…the mind seemed to grow giddy by looking so far into the abyss of time.” (The Bass Rock: Its Civil and Ecclesiastic History, “Geology of the Bass,” p. 82) Hutton also became famous for saying of the deep time of geology, “we find no vestige of a beginning, no prospect of an end.”

Deep time is also called geological time, because the order of change in geology, essentially invisible in terms of human time, is revealed in deep time. The deep time of the geological record is time enough for continents to move and reshape themselves, for mountain ranges to rise and fall, and for the planet entire to pass through a range of climates from a glaciated snowball earth to a steaming global swamp.


Image: Geologist, physician and naturalist James Hutton (1726-1797). This is Hutton’s portrait as painted by Sir Henry Raeburn in 1776.

For all this diversity, science has given the peculiar name of uniformitarianism, since although conditions and structures of the Earth change continually, the forces acting on the Earth are uniform over time. Charles Lyell especially developed geology along the lines of uniformitarianism, and this had a great influence on Darwin, who carried Lyell’s Principles of Geology along with him during his journey on the Beagle.

By the late twentieth century, however, Stephen J. Gould was able to argue in his paper “Is Uniformitarianism Necessary?” that to say that geology embodies uniformitarianism is nothing more than to say that geology is a science, and this is not controversial, so that it becomes unnecessary to explicitly formulate uniformitarianism as a scientific hypothesis, which freed up Gould and others studying deep time to consider other models of the past that are slightly less uniform but no less “deep” in the temporal sense (e.g., punctuated equilibrium).

Milankovitch cycles

Deep Time in Biology: Astrobiology

It took biologists time to come to a full realization of the antiquity of life on Earth, just as it took geologists time to formulate a time scale adequate to describe the processes of geology. The geologists got there first, but they got there with the help of paleontologists. William Smith, who drew the first modern geological map of England, dated rock strata by the fossils they contained and so established a correlation between geological time and biological time. (This is a story told in the excellent book by Simon Winchester, The Map that Changed the World.)

It is only in our time that we are coming to realize that the geology of the Earth and the life of our planet must be understood in a cosmological context. The formation of the Earth itself was a process that could be characterized as astrophysical before it was geological, and the astrophysics of our solar system continues to this day to shape the surface of our planet.

Life on Earth has shared the fate of the planet that hosts it, and this life has been shaped by cosmological events also. The earth, for example, wobbles in its orbit, and in fact the sun bobs up and down in the plane of the Milky Way as the galaxy spins. The wobbling of the Earth consists of eccentricity, axial tilt, and precession, which together are referred to as Milankovitch cycles, and which significantly affect the insolation of the Earth, i.e., the amount of sunlight reaching the Earth’s surface. This wobbling and bobbing has consequences for life on earth because it changes the climate – sometimes predictably and sometimes unpredictably. But regularity (or, if you prefer, uniformity) is at least partly a function of the length of time we consider.

Astrobiology has come about from the need to see life in its cosmological context, which is as much as to say that astrobiology is the biology of deep time. And we may need time even deeper than that provided by the geology of Earth to explain life. A recent well-publicized study, “Life Before Earth” (see preprint here) by Alexei A. Sharov and Richard Gordon, argued that projecting the complexity of life backward through time implies that life originated approximately 9.7 billion years ago, which is almost twice as old as the earth, which implies in turn that earth was “seeded” with life as soon as it was cool enough to support life (or sufficiently stable to sustain life), rather than independently arising on Earth.

Deep Time for Humanity: Big History

A scientific conception of deep time in geology and biology was the necessary prerequisite to the introduction of deep time into history, which latter was, from its ancient Greek inception up through the twentieth century, a humanistic rather than a scientific discipline. “History” was synonymous with written language, and the “historical period” was the period of human existence coincident with the use of written language.

The relatively recent emergence of what is now often called “Big History” is a result of many factors, not the least of which were the technologically facilitated dating methods that began to emerge in the middle of the twentieth century – most famously, carbon-14 dating. With the ability to date artifacts scientifically, a new and precise chronology emerged in parallel with written chronology, but this new chronology could be pushed far deeper in the past, and thus provide human beings with our own “deep time.”

The best known names in the field of Big History today – David Christian, Cynthia Stokes-Brown, and Fred Spier – have drawn heavily on the many special sciences to assemble an overall “big picture” view that places human history in the context of scientific historiography, wrapping up the whole in a chronology that extends from the Big Bang to the present day.

This Big History picture of human beings and the world in which they live has made us aware of the fact that our planet, our bodies, and our lives have been shaped by forces much larger than our planet, and even larger than our solar system. Ancient gamma ray bursts coming from deep within the galaxy may have affected the path of evolution of life on earth; closer to home, the Earth’s insolation has driven climate, and climate is a primary driver of evolution. So it seems that we are not only “star stuff” as Carl Sagan said, but our star stuff continues its relation to the stars even after it has become Earth-bound.

population bottleneck

Ignorance is Bliss

In the early history of our species, ignorance of existential risk was bliss. Human beings, their hominid predecessors, and the species that preceded them in turn, were fortunate merely to survive, i.e., to overcome the immediate existential risks posed by the local climate and conditions and to go on living from day to day. And when the small initial population of homo sapiens was geographically restricted to a small area of Africa, these local risks were profound and potentially existential.

It is widely postulated that human beings passed through an existential bottleneck about 70 thousand years ago (cf. population bottleneck), when there may have been only a few thousand representative individuals of our species alive. This existential bottleneck in human history was once theorized to be the result of the Mount Toba explosion, though recent research has suggested that this is not the case. There is an ongoing debate as to whether this existential bottleneck was a short, sharp event brought about through sudden climatic change (of the sort that might be triggered by a geophysical event) or a “long bottleneck” lasting up to 100,000 years. Whatever the cause, we got through by the skin of our teeth – though we did not know at the time how lucky we were.

Human beings were once an endangered species on the Earth. No longer. No we have made our way into every habitat on the planet (with the exception of Antarctica, unless one counts the scientific bases there) and have ambitions of controlling the climate of the entire planet. The trouble we have gotten ourselves into by the unrestricted burning of fossil fuels could yet be mitigated by geoengineering through the relatively simple and straight-forward means of placing a slight shade between ourselves and the sun (a “Dyson dot” in the terminology of Robert G. Kennedy, cf. Dyson Dots), but this is only one of many dangers that face us that must be understood on cosmological scales of time and space.

End Is Near

Why Existential Risk Now?

Why should existential risk be a concern for us now, when we have gotten along just fine for several hundred thousand years (and Earth before us for billions of years) without any awareness of existential risk? Are we not sounding a bit like Chicken Little proclaiming that the sky is falling? Do we not risk becoming just another doomsday prophet holding up a sign that says that the end of the world is coming?

Existential risk is a concern for us now because we are capable of understanding existential risk in a way that we would not have been able to understand existential risk in the past. The slow and incremental accumulation of scientific knowledge has made it possible for human beings to formulate the idea of deep time and to apply it in turn to geology, biology, cosmology, and even to human history. Just as a conception of deep time was a requisite for the modern scientific study of geology and biology, scientific historiography and big history was a requisite for the formulation of the idea of existential risk.

We have, essentially by dumb luck, made it thus far. This “dumb luck” may be the Great Filter of SETI and Fermi paradox debates, i.e., whatever it was the prevented a slew of other technological civilizations from emerging and crowding our little corner of the Milky Way, which now seems to us (now, that is to say, that we know how to listen) eerily silent. Some may credit it to divine providence rather than dumb luck.

However it happened that we survived, we have survived so far, but we have no guarantee of continued survival. We do, however, have knowledge on our side. Our scientific progress steadily adds to our knowledge of the world, and that makes us ever more clearly aware of our relationship to the wider world, which in this context means cosmology.

How consciousness of existential risk differs from Chicken Little and doomsday prophets is not only in its rational and scientific character, but, just as importantly, in the rational and scientific character of the response to existential risk. Scientific study of the universe can reveal to us the dangers that we face in great detail, and even the likelihood of our having to face them (a sterilizing gamma ray burst is not very likely, but a massive solar flare could very well burn out electrical power grids around the world). Moreover, the same science implies rational, scientific means of existential risk mitigation.

We are not limited to waving our arms and shouting that the sky is falling, or calling for our fellow man to repent because the end is nigh; we can formulate and execute specific existential risk mitigation strategies and measure their efficacy with the same sober scientific precision. And this is exactly what we need, because we can no longer count on being lucky. If the Great Filter still lies in the future, it will not be luck that gets us beyond it, but our own grit and determination.