If all humans died, when would the last light go out?

Summiz Holo

Power Sources After Humans Disappear

• Most lights wouldn't last long after humans disappear due to the major power grids going down quickly.
• Fossil fuel plants require a steady supply of fuel and would shut down soon after humans are gone.
• Nuclear reactors can run almost indefinitely in low-power mode, but would quickly shut down automatically without human oversight.
• Diesel generators in remote communities could run for days to months until fuel runs out.
• Off-grid geothermal plants could run for a few years without human maintenance but would eventually succumb to corrosion.
• Wind turbines can last longer without maintenance, potentially generating power for decades, but would eventually fail due to gearbox issues.
• Hydroelectric generators can operate on autopilot for several years, but electricity would have nowhere to go if the power grid is down.
• Battery-powered lights would all be off within a few dozen years due to self-discharge.
• Solar power sources could last longer since they are often hard to service and can provide illumination for extended periods.

Potential Light Sources

• Solar panels can last a century if kept free of dust and debris, supported by well-built electronics.
• Solar-powered lights in remote locations could be the last surviving human light source.
• Spent nuclear fuel is another potential light source due to Cherenkov radiation.
• Radioactive materials can emit light when particles travel through materials like water or glass.
• Cesium-137, a radioactive waste product, glows blue when mixed with glass and will still emit light centuries later.