Millions of objects are floating around the Earth in space, from small flakes of paint to rocket bodies several meters wide, posing danger to working spacecraft. Identifying, tracking and predicting the debris’ movements is a task the University of Arizona is taking on.
The drought in California has killed some 60 million trees in the past six years. Scientists are now trying to understand what makes some trees vulnerable and some remarkably resilient. To help them learn, they're using climbers as well as drones.