Many countries in Europe are using LED bulbs for outdoor lighting. They’re cheaper, last longer, and are more energy efficient. They’re seen as good for the environment. But a new study by academics at the University of Exeter concludes that they may be bad for sleeping — not just in humans but in other living things — and that this could have serious health implications. Marco Werman speaks to Alejandro Sanchez de Miguel, the lead author of the study, which appears in the journal Science Advances.