Astronaut Photos Taken Just 13 Years Apart Show a Major Shift in City Lights

Over the last 15 years or so, there’s been a huge shift in the way our cities are lit—and NASA astronaut Don Pettit has the photos to prove it.

Pettit has spent almost 600 days in space snapping images of metropolitan areas to document the global shift from orange sodium vapor lighting to white LED (light-emitting diode) lamps. And he’s now put together a thread on X (via PetaPixel) showing before and after comparisons for cities including Miami, Chicago, Las Vegas, Seoul, São Paulo, Hong Kong, and Mexico City. The differences are stark.

The old orange tint to street lighting was due to the technology that prevailed more than a decade ago. Electricity passed through sodium vapor, which gave off a strong, yellow-orange glow so everything would take on a particular sepia tinge at night.

Then LED technology arrived, specifically the blue LED needed to turn everything white (the discovery won the Nobel Prize in Physics). Cities soon started to switch, because LED lights last longer and use less energy, benefits for both city budgets and the environment.