With a population of more than 20 million”roughly 10 percent of Brazil's population”São Paulo ranked as the 10th largest urban area in the world in 2014. The city is no newcomer to the list. For two decades starting in the 1980s, São Paulo was the fourth largest city in the world. As the city has grown, its suburbs have spread, and its urban core has become more dense.
A piece of Africa”actually lots of pieces”began to arrive in the Americas in June 2014. On June 23, a lengthy river of dust from western Africa began to push across the Atlantic Ocean on easterly winds. A week later, the influx of dust was affecting air quality as far away as the southeastern United States.
Flowing south along Australia's western shore, the Leeuwin Current is an oddity. Unlike most currents that flow along the western shores of continents, it flows toward the pole (away from the equator), carrying warm tropical water into what would otherwise be a cold ocean.
A thin green line of the aurora borealis (northern lights) crosses the top of this night-time photograph taken by an astronaut on the International Space Station. The moon appears as a white disc just above the aurora. Airglow appears as a blue-white cusp along the Earth's limb. Moscow makes a splash of yellow light and is easily recognized by the radial pattern of its highways.
Brazil's national football stadium, the Estado NacÃonal, lies near the heart of the capital city of BrasÃlia. The roof appears as a brilliant white ring in this photograph taken from the International Space Station. The stadium is one of BrasÃlia's largest buildings. Renovation began in 2010, and now it is the second-most-expensive stadium in the world after London's Wembley Stadium.
Although Earth's ozone layer has been depleted during the last four decades by chlorofluorocarbons (CFCs) and similar chemical compounds, the changes are expressed differently at the North and South Poles. While a large ozone hole forms consistently each year over Antarctica, the concentration of Arctic ozone is much more variable. Why such differences?
The Kee Bird was a U.S. Air Force plane that made a crash landing after running into foul weather and other issues during a reconnaissance flight to the North Pole in 1947. The entire crew survived the crash, but then had to wait for more than three days to be found and rescued.
Springtime brings increased sunlight, bursts of nutrients and changing water conditions to the Gulf of Alaska, setting the stage for explosive blooms of aquatic plants and phytoplankton”and then the many crabs, fish and whales that feed on them.
Record-breaking temperatures and powerful Santa Ana winds fueled at least nine fires in southern California and northwestern Mexico between May 14“16, 2014. Cal Fire estimated that by the morning of May 16, more than 19,000 acres (7,700 hectares) had burned, and news reports said that more than 100,000 people were forced to evacuate at various stages of the fires.
An astronaut on the International Space Station recently took this night photograph of two of Belgium's major metropolitan areas.
