A global nuclear war on a distant Earth-twin would produce a radiation flare with a luminosity of ~10¹⁵ Watts, about 1% of Earth's reflected sunlight. This flare, lasting several hours, would emit unique ultraviolet and infrared signatures distinguishable from natural stellar flares.
If the exoplanet is within a few tens of light-years, instruments like the Hubble Space Telescope (UV) or the James Webb Space Telescope (IR) could, in principle, detect this transient signal—especially if the host star is a dim, nearby dwarf, allowing for spatial separation of the planet’s flare from the star’s light.
A global nuclear war on a distant Earth-twin would produce a radiation flare with a luminosity of ~10¹⁵ Watts, about 1% of Earth's reflected sunlight. This flare, lasting several hours, would emit unique ultraviolet and infrared signatures distinguishable from natural stellar flares.
If the exoplanet is within a few tens of light-years, instruments like the Hubble Space Telescope (UV) or the James Webb Space Telescope (IR) could, in principle, detect this transient signal—especially if the host star is a dim, nearby dwarf, allowing for spatial separation of the planet’s flare from the star’s light.