nLIGHT

This trending item is a blog post explaining a common misconception: the UV index measures the strength of ultraviolet radiation that causes sunburn and skin damage, not the warmth you feel from sunlight. That warm sensation comes mostly from infrared radiation, which is separate from UV. Readers on Hacker News appear to be sharing and discussing the post, apparently finding it a useful correction of a widespread misunderstanding about what the index actually tracks.

Scientists aimed light billions of times brighter than sunlight at water to test whether intense illumination could accelerate evaporation. Despite the extreme energy levels, the water did not evaporate any faster, a result that challenges assumptions about how light interacts with liquid surfaces. The unexpected finding is drawing attention from physicists studying evaporation and light-driven processes, as it suggests existing models may be missing something fundamental about energy transfer in water.