Funny they tested sunlight through glass, not direct sun. Glass removes most UV and a lot of the useful spectrum. Yet it still outperformed artificial lighting. Even the DILUTED version of sunlight is better than the LEDs in your house A filtered, watered down version of the sun still beats the ENGINEERED lighting we built to replace it. Take away UV. Strip parts of the infrared. Flatten the spectrum through a pane of glass. And it still works better. We spent decades designing LEDs, tuning color temperature, optimizing LUX. And a weakened version of the sun still beats it. Maybe the problem isn’t the engineering. Maybe the sun already figured this out.