| Moove that manure: Agricultural runoff a spreading public health issue Runoff from agriculture is the biggest polluter of the country's river and stream water, according to the U.S. Environmental Protection Agency (EPA), and it has been fingered for hypoxic dead zones and toxic red tide algae blooms . [More] rss.sciam.com |
Portrait of a Black Hole (preview) You have probably seen the TV commercial in which a cell phone technician travels to remote places and asks on his phone, “Can you hear me now?” Imagine this technician traveling to the center of our Milky Way galaxy, wherein lurks a massive black hole, Sagittarius A* (Sgr A*), weighing as much as 4.5 million suns. As the technician approached within 10 million kilometers of the black hole, we would hear his cadence slow down and his voice deepen and fade, eventually turning to a monotone whisper with diminishing reception. If we were to look, we would see his image turn increasingly red and dim as he became frozen in time near the black hole’s boundary, known as the event horizon.The technician himself, however, would experience no slowing of time and would see nothing strange at the location of the event horizon. He would know he had crossed the horizon only when he heard us say, “No, we cannot hear you very well!” He would have no way of sharing his last impressions with us--nothing, not even light, can escape from gravity’s extreme pull inside the event horizon. A minute after he crossed the horizon, the gravitational forces deep inside the hole would tear him apart. [More] rss.sciam.com |
Retirees Trade Work for Rent at Cash-Poor Parks An itinerant army of retirees is realizing dreams of life on the road in a way that benefits struggling state and national parks. nytimes.com |
Wyoming: Two Die Climbing Frozen Waterfall Yellowstone National Park officials say two Montana men died while trying to climb a frozen waterfall below the rim of the Grand Canyon of the Yellowstone River. nytimes.com |
White House to get (more) solar panels Following the lead of presidents from George W. Bush to Jimmy Carter , the Obama White House--or specifically the Obama family's living quarters--will get solar panels. While Carter's solar thermal panels are long gone (one of them is in China and the Obama White House last month rebuffed the return of another), photovoltaics installed by President Bush the Younger grace some of the other buildings on the White House grounds and, like most solar panels in the U.S., provide enough electricity to heat the pool, among other uses. But in the spring of 2011 a new solar hot-water heater and array of solar cells will begin producing some of the hot water and electricity consumed by the first family. [More] rss.sciam.com |