---
title: "The History of Now"
description: "Thomas Moynihan's *The History of Now* is an intellectual history of a single question: how much time lies behind the present, and how much ahead?"
type: "reading-notes"
authors:
  - "Thomas Moynihan"
published: "2025-05-10"
original_url: "https://historyofnow.antikythera.org/"
doi: "10.1162/ANTI.5CZS"
canonical_url: "https://antikythera.wiki/work/journal/historyofnow"
md_url: "https://antikythera.wiki/md/work/journal/historyofnow"
last_updated: "2026-08-23"
site: "Antikythera Wiki"
---

# The History of Now

> Independent, unofficial reading notes from Antikythera Wiki (https://antikythera.wiki). Written with AI from the published text, with citations; not by the work's author and not affiliated with Antikythera (https://antikythera.org). Read the original at the link below.

- **Authors:** Thomas Moynihan
- **Published:** 2025-05-10
- **Kind:** Journal · Journal article
- **DOI:** https://doi.org/10.1162/ANTI.5CZS
- **Original:** https://historyofnow.antikythera.org/
- **Length:** 16k words
- **This page:** https://antikythera.wiki/work/journal/historyofnow
- **Notes generated:** 2026-08-23

## Summary

[Thomas Moynihan](https://antikythera.wiki/people/thomas-moynihan)'s *The History of Now* is an intellectual history of a single question: how much time lies behind the present, and how much ahead? Built around a scrolling timeline of dated numerical estimates collected from the archives, the essay traces how European and then global thought moved from eternity (no bookends, so no location for "now") through scriptural chronology (a few thousand years past, a few centuries to go) to geology, thermodynamics, radioactivity, cosmology, and climate science, each of which redrew the ratio of past to future. Moynihan's claim is that this ratio is not an idle curiosity. Bounded time is the only kind in which decisions have lasting consequences, and the cosmological settlement of the 1960s removed the last refuge of recurrence. We have, he argues, one shot, on a planet whose habitable future is now shorter than its past, inside a universe whose habitable future is vastly longer than ours. That asymmetry is the essay's reason for existing.

## The argument

Moynihan opens with a contrast. Copernicus's displacement of Earth in space is celebrated, but the parallel discovery of Earth's place in time is hardly noticed. He narrates that second revolution through a dataset: every time a prominent figure put a number on the age of the world or the time it has left, the estimate is plotted as a horizontal bar, past to the left and future to the right. He declares the approach deliberately "unphilosophical": time here is just a magnitude of years, and what is at stake is the size of the estimates and their ratio.

The first move is conceptual rather than historical. Eternity and deep time are opposites, not neighbours. Where time has no limits, every possibility has already occurred and will occur again, so nothing can be irreversibly lost or gained and "now" cannot be located at all. Aristotle, Plato, Lucretius, and Cicero each drew this conclusion, and Moynihan places them on the graph as a single point rather than a bar. Depth, by contrast, requires measurement and therefore boundaries. Only in bounded time can some possibilities remain forever unrealised, which is exactly what makes one course of action rather than another consequential.

The historical narrative then runs through a series of reorientations. Christianity and Islam gave time a direction and an end, but an imminent one, so that medieval and early modern thinkers from Theophilus to Ussher and Newton placed "now" within a few centuries of apocalypse. Eighteenth-century geology turned from scripture to rock and produced the first physical experiments, Buffon's cooling iron spheres above all, which stretched the past into tens of thousands of years. The fossil record then revealed a prehuman past full of upheaval, and Moynihan notes how readily this new immensity was mistaken for infinity again: Hutton and Lyell rebuilt a steady-state Earth with "no vestige of a beginning, no prospect of an end."

Thermodynamics, the next stage, made the Sun the relevant clock and supplied a mechanism, gravitational contraction, that produced a cruelly short future. By the 1890s the scientific consensus placed humanity within a few million years of a frozen end, with four-fifths of the Sun's energy already spent. Moynihan underlines that this was a return, by physical argument, to the early Christians' position nearer the end than the beginning. Radioactivity reversed it. Skłodowska-Curie's demonstration that atoms expel energy without drawing on their surroundings gave the Sun a new fuel and the geologist a new clock; estimates of the future jumped a thousandfold, and Jeans coined the phrase that names the new self-image, "creatures of the dawn."

Cosmology then gave the universe itself a biography, and with it a second set of bars on the graph. Hubble's receding galaxies and Lemaître's primeval atom implied a beginning; Haldane and Goddard first calculated that nuclear rockets might let life outlast its star, so that life's upper bound became the lifespan of the cosmos rather than the Sun. The final reorientation is downward for Earth and upward for the universe. Fusion theory and then the runaway greenhouse effect, understood after the Venus probes, cut Earth's habitable future to around one billion years, less than a quarter of its past. The cosmic microwave background of 1964 meanwhile ended the last serious attempt, Hoyle's steady state, to restore eternity.

Moynihan's conclusion draws two consequences from this settlement. First, there are no cosmic replays. The comfort that Millikan and Koestler took in other Earths elsewhere in infinite time is gone; whatever happens on this planet happens once. Second, and in tension with the first, the universe is young. In an eternal universe, Hoyle could argue that interstellar life must already have arrived if it were possible. In a bounded and young one, unprecedented change at the largest scales becomes at least conceivable, and we may be living in the epoch before life spills beyond its planet. Moynihan refuses to call this inevitable or even good. His closing point is that fragility and freedom are two sides of the same discovery, and that the whole future is built on decisions made in the present.

## Section by section

### 0—Where Is Now?

The introduction explains the graph and states the stakes. Humans are "orienting creatures," and orientation in time is as necessary as orientation in space. Time is the medium in which actions matter, and a species that has become a planetary force needs to know how long its influence may last. Moynihan gives the current figures as a baseline (Earth 4.5 billion years old with about 1.5 billion habitable years left, the universe just under 14 billion years old with trillions ahead, our species around 300,000 years old) and confines the early sections to Earth's biography, since older generations assumed Earth and cosmos were born and would die together.

### 1—Scriptural Prophecy

This section runs from antiquity to 1700 and does the essay's conceptual work. In the ancient subsection Moynihan argues that belief in eternity was not foolish but underdetermined: before a global fossil and archaeological record, nothing could falsify the suspicion that history simply recurred. He quotes Aristotle on arts and sciences perishing and returning "infinitely often," and reads Cicero's indifference to durable legacies as the practical upshot. The contrast with deep time is stated here.

The medieval subsection describes the Crucifixion as the first universal reference point, an event that could not be repeated and therefore gave "before" and "after" a fixed meaning. The price was an imminent end. Theophilus (5,698 years past, 300 to go), Julius Africanus, Gregory of Tours, and Syncellus all placed the present near the close of a seven-millennium history. Moynihan's best example is Hartmann Schedel's 1493 chronicle: roughly three hundred printed pages, and six blank ones left for everything still to come. The early modern subsection adds Columbus's count of 155 years remaining, Ussher's 4004 BCE creation, and Newton's end around 2060, and quotes Thomas Browne's "'Tis too late to be ambitious" as the period's mood. It closes on John Craig, who in 1699 applied probability theory to the decay of testimony and computed that belief in the Gospels would reach zero, and the world end, in 3150 CE. Moynihan treats Craig as a hinge: wrong, but the first to replace scriptural counting with calculation.

### 2—Geology and Archeology

The Enlightenment subsection follows the turn from scripture to rock. Lomonosov calls Earth "the most senior Chronicler of all." Benoît de Maillet's *Telliamed* estimated two billion years past and another billion to come, but an orthodox editor struck the numbers out and the guess was forgotten. Buffon's experiment with heated iron spheres in his Burgundy forge produced the first physical estimate of both past and future (74,832 years old, 93,291 habitable years remaining). De Sales, Fourier, and Olbers each added methods, from orbital obliquity to the probability of cometary impact, the last yielding about 220 million years. The point of the catalogue is that the future was now expected to contain unprecedented things, hopeful and catastrophic alike.

The short Revolution subsection pairs political rupture with paleontological discovery: successive ages of fish, reptiles, and mammals showed the prehuman past to be full of change, and Balzac hailed Cuvier as "the greatest poet of our century." The Reaction subsection records the relapse. Hutton's rule of explaining the past by observable present causes was sound method, but over-applied it produced a steady-state Earth and a literally measureless lifespan; Lyell expected dinosaurs to return. Moynihan adds that even after Earth gained bookends, the cosmos remained infinite, so that extinction could still be treated as a "local affair": de Sales promised renewal elsewhere, and Fourier expected souls to transmigrate to other globes.

### 3—Thermodynamics

The Industrial subsection ties the science of heat to the coal that powered it and quotes Tyndall's 1863 hymn to the Sun as the source of every raised hammer and thrown shuttle. Thermodynamics established that spent energy cannot be recouped, so the Sun must die, and life's lifespan is therefore the Sun's. Without knowledge of atomic energy, the best available mechanism was Thomson and Helmholtz's gravitational contraction. Thomson's 1854 calculation gave a past of 32,000 illuminated years and a future of less than 300,000; his estimate of Earth's age settled around 20 million years.

The Decadence subsection follows the consensus as it hardened around roughly ten million years of future, while physicists and biologists disputed an age between 20 and 100 million years. Robert Ball's 1892 statement that the Sun had spent four-fifths of its endowment, so that the race's remaining span could be counted "on the fingers of one" hand, is the emblem. Huxley's 1893 Oxford lecture pictured a senile biosphere of lichen and moss, and an audience member's protest at "sheer waste, on the most gigantic scale" shows how the short future was felt. Moynihan stresses the irony that physical science had reproduced the medieval placement of "now."

### 4—Radium

The single subsection covering the 1900s and 1910s narrates the reversal. Skłodowska-Curie's isolation of radium in 1902, and her proof that decaying atoms release energy without cooling, prompted George Darwin within a year to suggest multiplying the cosmic timescale by ten or twenty. The *Daily Mail* announced "radium to the rescue"; Rutherford and then Eddington (15 billion years of sunshine, with the Kelvin-Helmholtz theory dismissed as a "corpse") extended the future by orders of magnitude; Jeans's annihilation theory of 1928 produced a trillion years. Moynihan includes Lester Frank Ward's odd 1907 estimate from a supposed parallel between Earth and an older, inhabited Mars, for Ward's conclusion that humanity's golden age lies ahead. The centrepiece is Jeans's 1929 image of a stamp on a penny on a twenty-metre obelisk, with the future a pile of stamps as high as Mont Blanc, and his description of humanity as "creatures of the dawn," a baby just learning continence. The section ends with radioactivity's second gift: radiogenic heat in the crust demolished Kelvin's argument from Earth's internal warmth, and decay rates gave Holmes and others the hourglass that proved Earth billions of years old.

### 5—Cosmology

The 1920s and 1930s subsection introduces the purple bars for the universe as a whole. Hubble's receding galaxies implied a compact beginning and a rarefied end; Lemaître's primeval atom, explicitly modelled on Skłodowska-Curie's disintegrating elements, supplied a mechanism. Early ages ranged from Friedmann's 10 billion to Jeans's 200 trillion years before the short timescale prevailed. Moynihan then turns to the consequence that matters most for his argument: if atomic power could drive rockets, life's future need not be coupled to its star. Goddard's 1913 notebooks on interstellar migration as insurance against the Sun's cooling, and Haldane's 1927 estimate of eighty million million years for the galaxy, ending "And there are other galaxies," are presented as the first quantitative estimates of life's cosmic upper bound.

The 1940s and 1950s subsection records the first downward revision. Bethe's fusion model was less efficient than Jeans's annihilation, so the Sun's future fell to around ten billion years, and it would end in fire rather than frost as the star expanded. Jeans's revised edition of 1945 accordingly shrinks the pile of stamps from Mont Blanc to the towers of Westminster Abbey.

### 6—Climatology

The 1960s subsection begins with Gamow's five-billion-year Sun and then treats Hoyle, Bondi, and Gold's steady-state cosmology as the last return of eternity, with the same attraction the earlier versions had: it insulates from loss. Penzias and Wilson's detection of the cosmic microwave background in 1964 is presented as the decisive refutation. Moynihan spends the rest of the subsection on what this means. He cites Millikan's 1929 assurance that in an infinite universe there will always be some Earth where humanity continues, and Koestler's 1953 diagnosis that the hydrogen bomb explained the sudden interest in life on other stars. Against these he sets Loren Eiseley's reflection that "the same hands will never twice build the golden cities of this world."

The 1970s subsection is the essay's account of how Earth's future was cut. Mariner 2 and Venera 4 showed Venus to be a pressurised furnace rather than a tropical younger sister, and Ingersoll's 1969 runaway greenhouse model explained how. The same model implied that an expanding Sun would render Earth uninhabitable long before engulfing it. Öpik's 1973 estimate of one billion years has since become the consensus. Moynihan summarises the whole trajectory here: centuries in the 1600s, tens of thousands of years in the 1700s, tens of millions in the 1800s, trillions in the early 1900s, one billion today, against a past of just over four billion. On the terrestrial view, we are near the end. Whether that should depress depends on whether one takes a terrestrial or a cosmic perspective.

The 1980s and 1990s subsection supplies the cosmic view through "physical eschatology." A 1983 *Scientific American* team forecast proton decay around 10^32 years and the evaporation of black holes by 10^100; Islam and then Adams and Laughlin's *The Five Ages of the Universe* (stelliferous, degenerate, black hole, dark) place the end of complex life at 10^40 to 10^50 years. Moynihan flags that proton decay is hypothetical, but takes the broad consensus as settled: the universe will become uninhabitable, at a distance measured in numbers with dozens of zeros.

### 7—Our Precarious Present

The conclusion restates the current figures and adds two reflections. Each person is in a physical sense 13.8 billion years old, because that is how long the universe needed to forge heavy elements through generations of stars, a point Moynihan credits to Hoyle's own work. And each is the product of a genetic memory bank billions of years deep, in which every entrenched feature could have been otherwise. The ethical argument follows. Bookended time falsifies the assumption of cosmic replays, so the present has "one shot and one shot only." But bookended time also removes an old argument against large-scale novelty. Moynihan quotes Hoyle's objection to deep space travel (if it were possible, others would have arrived already) and observes that it only works in an eternal universe. In a young one, it is at least plausible that we live before the epoch in which life reorganises matter beyond its planet. He declines to say whether such an outcome would be good and denies that there is any trend or fate. The closing sentence returns to the garden that must be tended first, which is now the whole planet.

## Key concepts

- **[Temporal Orientation](https://antikythera.wiki/terms/temporal-orientation)** — The activity of locating "now" by estimating how much time lies behind and ahead. Moynihan presents it as a species-level counterpart to the Copernican location of Earth in space, and as a prerequisite for taking long consequences seriously.
- **[Shallow Eternity vs. Deep Time](https://antikythera.wiki/terms/shallow-eternity-vs-deep-time)** — The essay's central distinction. Eternity is boundless and therefore flat: all possibilities recur, nothing is lost, and no present can be located. Deep time is enormous but bounded, and only in bounded time can decisions foreclose possibilities.
- **Bookends** — Moynihan's term for a determinate beginning and end, first acquired by Earth (against Hutton and Lyell) and then by the cosmos (against Hoyle). Bookends are what convert magnitude into depth.
- **Ratio of past to future** — The quantity the graph visualises. The essay's history is a history of this ratio, which has swung from near-the-end (medieval chronology, Victorian thermodynamics, today's terrestrial view) to near-the-beginning (radium, cosmology).
- **[Creatures of the Dawn](https://antikythera.wiki/terms/creatures-of-the-dawn)** — Jeans's 1929 phrase for a humanity that has only just appeared relative to the future available to it. Moynihan revives it at cosmic scale, where the habitable future still dwarfs the past.
- **[One Shot (No Cosmic Replays)](https://antikythera.wiki/terms/one-shot-no-cosmic-replays)** — The moral consequence of cosmic bookends. With no infinite time in which Earth recurs elsewhere, extinction ceases to be a "local affair" and the present's decisions become unrepeatable.
- **Physical eschatology** — The study of the far future of the universe, from proton decay to black hole evaporation. Moynihan uses its results to set the outermost bound on how long life anywhere might persist.
- **Recurrence of eternity** — The pattern Moynihan identifies in which each enlargement of time is mistaken for infinity (Hutton after Cuvier, Hoyle after Hubble), because limits one cannot see are assumed not to exist.

## Connections

- [Planetary Sapience & Planetary Stupidity: a Bildungsroman for the Baby Noosphere](https://antikythera.wiki/work/journal/babynoosphere) is Moynihan's companion lecture in the same issue, and the two should be read together. It supplies the nineteenth-century "psychozoic" lineage and the Lem material that *The History of Now* only gestures at. There is a mild tension: the lecture entertains Lem's "New Cosmogony," in which the universe may already be an artefact of ancient precursors, whereas this essay argues that in a young universe we may be the first thinking world. Both are offered as live possibilities rather than a settled position.
- [The Long L](https://antikythera.wiki/work/journal/longl) builds directly on this essay. Its note on "rare earth" solutions to the Fermi question cites Moynihan for the possibility that Earth is among the first intelligent planets in a sparsely populated cosmos, and its insistence that habitability must be actively cultivated is the programmatic form of Moynihan's closing injunction to tend the garden. Agreement.
- [Existential Technologies](https://antikythera.wiki/work/journal/existentialtech) argues with the ethical use Moynihan makes of deep time. Its first section, on the amorality of deep time, follows Lem in doubting that present moral commitments can be projected across hundreds of millions of years, and criticises long-termist futurology on those grounds. Moynihan does not endorse long-termism by name, but his claim that the whole future is built on present decisions is the kind of reasoning that essay treats with suspicion.
- [Cognitive Infrastructures](https://antikythera.wiki/work/journal/coginfra), and especially the Chronoseed paper within it, takes up the practical problem the essay implies: how to transmit anything across the bounded but deep future. Where Moynihan establishes that legacies can last, Chronoseed asks what medium could carry them.
- [The Noocene](https://antikythera.wiki/work/journal/noocene) shares the essay's Copernican framing, reading post-Copernican astronomy as the model for a philosophy that accepts what calculation reveals about the world. Moynihan's time revolution is the temporal half of the same story.
- The symposium transcript in [Planetary Sapience](https://antikythera.wiki/work/journal/planetarysapience) records Moynihan presenting the prototype graph and dataset in 2023, with the title credited to Bratton. It is the clearest record of the project's origin.
- Bratton's [Planetary Sapience](https://antikythera.wiki/work/media/noema-planetary-sapience) frames intelligence as a planetary-scale process that emerged once and may extend beyond its planet. Moynihan's essay gives that framing its temporal coordinates, and his refusal to treat such extension as a trend or fate is a check on the more teleological readings.


## Terms used

- [Creatures of the Dawn](https://antikythera.wiki/terms/creatures-of-the-dawn)
- [Generative Time Capsule](https://antikythera.wiki/terms/generative-time-capsule)
- [Historical Things](https://antikythera.wiki/terms/historical-things)
- [Inductive Confidence (planetary)](https://antikythera.wiki/terms/inductive-confidence-planetary)
- [One Shot (No Cosmic Replays)](https://antikythera.wiki/terms/one-shot-no-cosmic-replays)
- [Shallow Eternity vs. Deep Time](https://antikythera.wiki/terms/shallow-eternity-vs-deep-time)
- [Societal Time Literacy](https://antikythera.wiki/terms/societal-time-literacy)
- [Temporal Orientation](https://antikythera.wiki/terms/temporal-orientation)

## Related works

- [The Long L](https://antikythera.wiki/work/journal/longl)
- [Cognitive Infrastructures](https://antikythera.wiki/work/journal/coginfra)
- [The Noocene](https://antikythera.wiki/work/journal/noocene)
- [Existential Technologies](https://antikythera.wiki/work/journal/existentialtech)
- [Planetary Sapience Symposium](https://antikythera.wiki/work/journal/planetarysapience)