A dying world could be the loudest thing in the universe – at least when viewed through the lens of an astronomer’s telescope.’ This disturbing truth encapsulates the essence of the Eschatian Hypothesis put forward by Dr. David Kipping. In a complete reversal of the usual aliens-meet-humans endgame, Dr. Kipping argues that the first genuine human contact with aliens could be with a civilization that is plummeting towards the end of its days.
Kipping takes his comparative example from astrophysics, where many objects appear brightest just before disappearing. Red giant stars, for instance, expand brilliantly in their final moments, while supernovae, although rare, temporarily outshine whole galaxies. However, as Kipping correctly points out, this is a detection bias, where astrophysicists usually discover either extreme or transient phenomena, but not the more commonly occurring, stable ones. Kipping now uses this observation to extrapolate what technosignatures may potentially appear brightest.
Such “loud” civilizations might be in trouble, with their energy consumption jumping because of disasters. In a steady state, advanced civilizations could be very energy-efficient in their activities, keeping waste heat and radiation to a minimum. However, disaster scenarios such as nuclear wars, global climate disasters, or unchecked industrial pollution might cause enormous and observable energy pulses. A global nuclear war on a planet similar to Earth, as described in the scenario by Annie Jacobsen, might emit bursts of radiation with powers of 10¹⁵ watts, one percent of Earth’s reflected solar luminosity in intensity, with sharp UV and IR spectra distinguishable among the vast solar spectra if the planet circled a dim red star rather than a normal-sized star like the Sun in our solar system.
The consequences of such destruction would be years of lingering issues in atmospheric chemistry. Nuclear fire balls would create nitride oxides, releasing radioactive isotopes that would be traceable for years, whereas industrial failure might result in fluorinated greenhouse gases that have lifetimes of more than 1,000 years. All these gases would have no background levels in natural processes and would therefore provide a conspicuous signature of technological presence. The James Webb Telescope would be capable of identifying these gases in exoplanet atmospheres.
Kipping goes so far as to speculate that the legendary “Wow!” signal of 1977 might have been a desperate message from an endangered civilization. Although new work indicates a possible natural explanation for this signal via hydrogen maser radiation, it is symptomatic of the challenge of distinguishing astrophysical phenomena from potential artificial signals.
According to Eschatian theory principles, search strategy priorities for astronomers include wide-field surveys to detect transient phenomena unusual changes in brightness, unusual spectral distributions, unusual patterns of motion not consistent with known astrophysical processes over surveys for continuous narrow-band signals.
The science of technosignatures also verifies such a strategy’s validity. The present state of SETI research merely scratches the surface of the cosmic sea, with radio wave exploration of only a portion of the “water hole” spectrum and a selected portion of the celestial map. Extension of detection to multi-spectral phenomena, such as pulsed lasers or waste heat, would provide a better chance of picking up an unusual occurrence. According to the wise insights of Penn State’s Sofia Sheikh, studying our own detectable signals can help refine our approach. Radio signals of planetary radar could be detected up to 12,000 light-years away, while NO2 pollution could be detected at 5.7 light-years away.
Another way that the Eschatian Hypothesis supports a detection theory of the “loud” type is related to the thermodynamic limits of a civilization’s lifespan as set by scientists Manasvi Lingam and Amedeo Balbi. Studies affirm that the exponential expansion of energy output would leak heat into space at a point that could make a planet inhabitable for less than 1,000 years. As a matter of fact, civilizations that don’t reach a balance may not survive long enough for a detection theory to be upheld. Technologically speaking, this represents a new paradigm for the search.
Rather than envisaging spectacular alien megastructures or stable Dyson spheres, astrophysicists may uncover evidence of self-destruction, such as planetary flares, scars on atmospheres, and weird energy signatures. Such evidence, as poignant as it is, may prove the greatest chance yet for humankind to prove that it is not alone and that is by glimpsing another civilization at the exact point of its self-destruction.
