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

Summary

In a hypothetical scenario where humans vanish, the majority of artificial lights would extinguish quickly due to power grid failures. Nuclear reactors might persist, but automatic shutdowns would ensue upon grid failure. Off-grid sources like diesel generators could last days to months, while geothermal plants might operate for years before succumbing to corrosion. Wind turbines could endure for decades, and solar-powered lights, especially in remote areas, could potentially be the last to go, shining for a century if maintained. Intriguingly, the glow from radioactive waste, such as cesium-137, could outlast all other light sources, persisting for centuries as a haunting reminder of human presence.

Takeaways

• 🌐 Without human intervention, most artificial light sources would go out quickly as power grids fail.
• ⚙️ Fossil fuel plants would shut down within hours due to the lack of human-operated supply chains.
• 🔋 Nuclear reactors could theoretically run indefinitely with their fuel, but automatic safety measures would likely shut them down.
• 🏭 Geothermal plants might operate for a few years without maintenance, but would eventually succumb to corrosion.
• 🌬️ Wind turbines are designed for minimal maintenance and could last decades, but would eventually stop due to mechanical failure.
• 💧 Hydroelectric generators could continue running for several years without human intervention.
• 🔋 Battery-powered lights would be off within a few decades due to self-discharge and lack of maintenance.
• ☀️ Solar power is a promising long-term light source, with the potential to last a century if properly maintained.
• 🧪 Spent nuclear fuel emits Cherenkov radiation, which could provide a faint glow for centuries due to the half-life of radioactive materials.
• 🕯️ The last light on Earth might come from the glow of radioactive waste, outlasting all other artificial light sources.

Q & A

How long would it take for the last artificial light source to go out if humans disappeared?

It's difficult to give an exact time frame as it depends on various factors, but some light sources could last for centuries.

What would happen to the major power grids without human intervention?

The major power grids would likely experience a rapid series of cascading failures leading to a blackout within the first few hours.

How would fossil fuel plants be affected by the disappearance of humans?

Fossil fuel plants would start shutting down in the first few hours due to the lack of a steady supply of fuel and human intervention.

What is the potential longevity of nuclear reactors without human operation?

Nuclear reactors could theoretically run indefinitely with a settled core, but most would automatically shut down if something went wrong.

How long could diesel generators in remote communities last without refueling?

Diesel generators could run until their fuel tanks are empty, which could be anywhere from days to months.

What is the expected lifespan of geothermal plants without human maintenance?

Geothermal plants might run for a few years without maintenance, but would eventually succumb to corrosion.

How long could wind turbines operate without regular maintenance?

Modern wind turbines are typically rated to run for 3 years without servicing, but some could potentially last for decades.

How long would generators that convert falling water into electricity continue to work?

Generators converting falling water into electricity, like the Hoover Dam, could run on autopilot for several years.

What is the expected lifespan of battery-powered lights without human intervention?

Battery-powered lights would all be off in a few dozen years due to self-discharge, regardless of usage.

How long could solar-powered lights last in remote locations?

Solar-powered lights could potentially last for a century if the panels are kept free of dust and the electronics are well-built.

What is the potential longevity of Cherenkov radiation from radioactive waste?

Cherenkov radiation from radioactive waste, such as cesium-137, could still be glowing with 1% of its original radioactivity two centuries later.