UCLA scientists develop mineral sunscreen without the chalky white cast - Science Daily

It's one of the oldest questions humans have asked, and as far as we know, our planet is the only one that holds the answer. Earth is also the only planet we know of with plate tectonics, the slow-motion churn of its outer shell that recycles rock, reshapes continents and cycles the nutrients that could feed life. A new international study, published in Nature Geoscience and led by Dr. Hugo Moreira, a Royal Society university research fellow at the University of Portsmouth, is helping us better understand the origins of life by tracing the deep history of Earth's oxygen back billions of years, to a time when the planet and its atmosphere looked nothing like they do today.