Human skin color reflects an evolutionary balancing act tens of thousands of years in the making. There’s a convincing explanation for why human skin tone varies as a global gradient, with the darkest populations around the equator and the lightest ones near the poles. Put simply, dark complexion is advantageous in sunnier places, whereas fair skin fairs better in regions with less sun. That may seem obvious, considering the suffering that ensues when pale folks visit the beach. But actua ...read more

Many cities, in recent years, have initiated tree planting campaigns to offset carbon dioxide emissions and improve urban microclimates. In 2007, New York City launched MillionTrees NYC, a program designed to plant 1 million new trees along streets, in parks and on private and public properties by 2017. They hit their goal two years ahead of time. These programs are popular for a reason: Not only do trees improve the city’s appearance, but they also mitigate the urban heat island effec ...read more

The last male northern white rhinoceros — his name was Sudan — died in March, leaving only two members of the subspecies behind: his daughter and granddaughter. In the past, those stark facts would have spelled the end. But researchers at the San Diego Zoo’s Institute for Conservation Research — home to a frosty menagerie known as the Frozen Zoo — are working to give northern white rhinos a second chance. Since 1975, the institute has been collecting tissues from c ...read more

One of the most cherished science fiction scenarios is using a black hole as a portal to another dimension or time or universe. That fantasy may be closer to reality than previously imagined. Black holes are perhaps the most mysterious objects in the universe. They are the consequence of gravity crushing a dying star without limit, leading to the formation of a true singularity – which happens when an entire star gets compressed down to a single point yielding an object with infinite dens ...read more

We don't tend to think of the British Isles as a land of volcanoes. However, over geologic timescales, things can be very different. ~50-60 million years ago, the North Atlantic Ocean was opening and the area around the modern North Sea was rife with volcanic activity. Much of these eruptions were lava flows, producing flood basalt provinces similar to the Columbia River Basalt -- but now mainly under the waters and ice of the North Atlantic and Greenland. Yet, over in what is called the Bri ...read more