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Janus Observatory

S6

Sword of Damocles

Nanoscale engineering regulates biological processes inside a technosphere that has transformed Mars and begun work on Venus. The system faces existential risk from fragile, precisely calibrated life support managed by laboring populations.

Illustration of future S6. Engineered life-support plating covers most of Earth, land and sea, under a heavy chemical haze. Warning lights pulse across a system held in precise balance, and an orbital regulator hangs over it on a single tether. The description and data are on this page.

Population in 1,000 years
200 billion≈ 25 × the study’s Earth population
Energy used per year
20 thousand EJ a year≈ 34 × the study’s Earth energy use2 × 10²² joules a year
Trend
Growing
Growth rate
0.35% a year
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 S6
EconomyScarcityTable 2, p. 5 ↗
PoliticsRule by fewTable 2, p. 5 ↗
SocietyHierarchicalTable 2, p. 5 ↗
Technology and natureNature sits inside technologyIn the paper: The biosphere is a proper subset of the technosphereTable 4, p. 7 ↗
Centers of technologyTwo centersIn the paper: BipolarTable 4, p. 7 ↗
How technology developsDesigned and directedTable 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

  • CO2 + CFC-11/12
  • CF4
Large Interferometer for Exoplanets
Thermal glow
04

Sun-as-a-lens telescope

  • large surface features (Earth, Mars)
Solar Gravitational Lens
Resolved surface imaging
05

Visiting space probe

  • large surface features (Venus, Earth, Mars)
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 S6
WorldMarkAmountMeasured asSource
EarthIndustrial pollution210abundance relative to Earth 2024Table 6, p. 14 ↗
MoonIndustrial pollution17abundance relative to Earth 2024Table 6, p. 14 ↗
MarsIndustrial pollutionS5 and S6 include artificial greenhouse gases for terraforming Mars.1000abundance relative to Earth 2024Table 6, p. 14 ↗
VenusIndustrial pollutionS5 and S6 indicate O2 production and depletion of other constituents for terraforming Venus.0.5abundance relative to Earth 2024Table 6, p. 14 ↗
EarthAgricultural pollutionNot givenabundance 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 illumination0.4intensity relative to Earth 2024Table 6, p. 14 ↗
MoonArtificial illumination8.3intensity relative to Earth 2024Table 6, p. 14 ↗
MarsArtificial illumination0.24intensity relative to Earth 2024Table 6, p. 14 ↗
VenusArtificial illumination0.02intensity relative to Earth 2024Table 6, p. 14 ↗
EarthSurface modification0.8fraction of planetary surfaceTable 6, p. 14 ↗
MoonSurface modification0.9fraction of planetary surfaceTable 6, p. 14 ↗
MarsSurface modification0.9fraction of planetary surfaceTable 6, p. 14 ↗
VenusSurface modification0.05fraction of planetary surfaceTable 6, p. 14 ↗
EarthSatellite belt10000density relative to Earth 2024Table 6, p. 14 ↗
MoonSatellite belt10000density relative to Earth 2024Table 6, p. 14 ↗
MarsSatellite belt50000density relative to Earth 2024Table 6, p. 14 ↗
VenusSatellite belt1000density relative to Earth 2024Table 6, p. 14 ↗
EarthContaminated aerosol100density relative to Earth 2024Table 6, p. 14 ↗
MoonContaminated aerosol100density relative to Earth 2024Table 6, p. 14 ↗
MarsContaminated aerosol500density relative to Earth 2024Table 6, p. 14 ↗
VenusContaminated aerosol10density 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

  • Radio leakage
  • Optical communication
  • Planetary defense radar
  • Asteroid mining
  • Fusion propulsion
  • Kuiper belt mining
  • Quantum communication
Table 8, p. 17 ↗

Collapse and recovery

Collapses in every run; first collapse occurs within 200 years on average and about 4.5 collapses occur.

Time spent active
Not stated in the text
Collapses
About 4.5 on average
How precise
Approximate, from the paper’s text
Figure 3, p. 8 ↗

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 S6
Gas or propertyValueUnitSource
Mean Temperature300KTable 1, p. 4 ↗
CO230000ppmTable 1, p. 4 ↗
CH40.11ppmTable 1, p. 4 ↗
NOx400ppbTable 1, p. 4 ↗
N2O34ppbTable 1, p. 4 ↗
NH30.4ppbTable 1, p. 4 ↗
CFC-1148ppbTable 1, p. 4 ↗
CFC-12110ppbTable 1, p. 4 ↗
NF3530pptTable 1, p. 4 ↗
SF62300pptTable 1, p. 4 ↗
CF411000pptTable 1, p. 4 ↗
SO2, Stratospheric26ppbTable 1, p. 4 ↗
Na Emission0.05erg 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.