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Janus Observatory

S4

Living with the Land

After the peak of high technology, people live by subsistence, simple tools, and artisanal crafts. Rituals and oral traditions reinforce belonging to the biosphere, while settlements migrate with seasonal and planetary cycles.

Illustration of future S4. Wild forests, grasslands and restored ice cover Earth. People live in small seasonal camps that drift with the year, beside the overgrown ruin of a former high-technology age. One derelict satellite still circles. The description and data are on this page.

Population in 1,000 years
400 million≈ 0.051 × the study’s Earth population
Energy used per year
30 EJ a year≈ 0.051 × the study’s Earth energy use3 × 10¹⁹ joules a year
Trend
Stable
Growth rate
No rate given
What is “the study’s Earth”?

The scenario study measures every future against a fixed Earth: 7.9 billion people, each using 75 gigajoules of energy a year (592.5 EJ per year in total). An exajoule (EJ) is a billion billion joules.

The multipliers are rounded and count every world a civilization lives on. The reference is the study’s model, not a measurement of Earth today, and says nothing about how many people a planet can support.

Planetary technosignatures: industrial pollution scaling, p. 12 ↗Table 9 caption and Section 5.1, p. 18 ↗

Source: the scenario study, Table 9 ↗

What this future is like.

How the scenario study describes this civilization. Where it offers more than one option, both are shown. Each line links to the table it came from.

Profile of S4
EconomyScarcityTable 2, p. 5 ↗
PoliticsRule by fewTable 2, p. 5 ↗
SocietyHierarchicalTable 2, p. 5 ↗
Technology and natureThey partly overlapIn the paper: Some common elements with the biosphere; neither set is equalTable 4, p. 7 ↗
Centers of technologyOne centerIn the paper: UnipolarTable 4, p. 7 ↗
How technology developsEvolved and emergentTable 4, p. 7 ↗
Smallest engineering scale1 nm to 1 μmTable 4, p. 7 ↗

What a telescope could see.

Five instruments, from the observing study. “Nothing listed” means the study lists no sign for that instrument—not that this civilization has no technology.

01

Optical space telescope

  • CO2 + NO2
Habitable Worlds Observatory
Reflected light
02

Radio telescope array

Nothing listed for this instrument.

Radio array
Radio signals
03

Infrared telescope array

Nothing listed for this instrument.

Large Interferometer for Exoplanets
Thermal glow
04

Sun-as-a-lens telescope

Nothing listed for this instrument.

Solar Gravitational Lens
Resolved surface imaging
05

Visiting space probe

  • large surface features (Earth)
Deep-space probe
Close-up exploration
Source: the observing study, Figure 6 ↗

Marks on each world.

Pollution, night lights, reshaped land, satellites and haze on Earth, the Moon, Mars and Venus, compared with Earth today. Each kind of mark keeps its own units; we don’t squash them onto one scale.

Marks on each world in S4
WorldMarkAmountMeasured asSource
EarthIndustrial pollution0.038abundance relative to Earth 2024Table 6, p. 14 ↗
MoonIndustrial pollutionNot givenabundance relative to Earth 2024Table 6, p. 14 ↗
MarsIndustrial pollutionS5 and S6 include artificial greenhouse gases for terraforming Mars.Not givenabundance relative to Earth 2024Table 6, p. 14 ↗
VenusIndustrial pollutionS5 and S6 indicate O2 production and depletion of other constituents for terraforming Venus.Not givenabundance relative to Earth 2024Table 6, p. 14 ↗
EarthAgricultural pollution0.29abundance relative to Earth 2024Table 6, p. 14 ↗
MoonAgricultural pollutionNot givenabundance relative to Earth 2024Table 6, p. 14 ↗
MarsAgricultural pollutionNot givenabundance relative to Earth 2024Table 6, p. 14 ↗
VenusAgricultural pollutionNot givenabundance relative to Earth 2024Table 6, p. 14 ↗
EarthArtificial illumination0.025intensity relative to Earth 2024Table 6, p. 14 ↗
MoonArtificial illuminationNot givenintensity relative to Earth 2024Table 6, p. 14 ↗
MarsArtificial illuminationNot givenintensity relative to Earth 2024Table 6, p. 14 ↗
VenusArtificial illuminationNot givenintensity relative to Earth 2024Table 6, p. 14 ↗
EarthSurface modification0.0006fraction of planetary surfaceTable 6, p. 14 ↗
MoonSurface modificationNot givenfraction of planetary surfaceTable 6, p. 14 ↗
MarsSurface modificationNot givenfraction of planetary surfaceTable 6, p. 14 ↗
VenusSurface modificationNot givenfraction of planetary surfaceTable 6, p. 14 ↗
EarthSatellite belt0.015density relative to Earth 2024Table 6, p. 14 ↗
MoonSatellite beltNot givendensity relative to Earth 2024Table 6, p. 14 ↗
MarsSatellite beltNot givendensity relative to Earth 2024Table 6, p. 14 ↗
VenusSatellite beltNot givendensity relative to Earth 2024Table 6, p. 14 ↗
EarthContaminated aerosolNot givendensity relative to Earth 2024Table 6, p. 14 ↗
MoonContaminated aerosolNot givendensity relative to Earth 2024Table 6, p. 14 ↗
MarsContaminated aerosolNot givendensity relative to Earth 2024Table 6, p. 14 ↗
VenusContaminated aerosolNot givendensity relative to Earth 2024Table 6, p. 14 ↗

Beyond Earth, and over time.

Signs of technology across the Solar System come from the scenario study. Collapse and recovery come from a separate study that simulates each future for 1,000 years.

Signs beyond Earth

None listed.

Table 8, p. 17 ↗

Collapse and recovery

Collapses in every run and has the lowest reported mean duty cycle, with frequent deep collapses.

Time spent active
38% on average
Collapses
About 6.6 on average
How precise
Approximate, from the paper’s text
Figure 3, p. 9 ↗

The air on this Earth.

The gases and temperature the observing study gives this future’s Earth. Where the paper leaves a value out, we show “Not given” rather than zero.

Show the atmosphere table
Atmosphere of Earth in S4
Gas or propertyValueUnitSource
Mean Temperature288KTable 1, p. 4 ↗
CO2290ppmTable 1, p. 4 ↗
CH40.96ppmTable 1, p. 4 ↗
NOx0.17ppbTable 1, p. 4 ↗
N2O220ppbTable 1, p. 4 ↗
NH34.3ppbTable 1, p. 4 ↗
CFC-11Not givenppbTable 1, p. 4 ↗
CFC-12Not givenppbTable 1, p. 4 ↗
NF32.5pptTable 1, p. 4 ↗
SF611pptTable 1, p. 4 ↗
CF487pptTable 1, p. 4 ↗
SO2, StratosphericNot givenppbTable 1, p. 4 ↗
Na Emission0.042erg s^-1 cm^-2Table 1, p. 4 ↗
Laser Emission, 1.064 umNot givenMWTable 1, p. 4 ↗

Objects from this world.

Stories and objects artists made inside this future. They’re fiction, not evidence. Works whose creators reserve all rights are linked, never copied here.

01S4

Luna's Travels: Sketches of the Eastern Crescent Plains

Clara Mae Gonzales

All rights reservedView the original ↗