On the horizon
The ability to peer inside a comet might seem reminiscent of a Star Trek episode, but scientists revealed that they are now more intimately knowledgeable of both the materials inside of these objects and how they may have formed in our solar system's early years.
After NASA's Deep Impact spacecraft collided with comet Tempel 1 on July 4, 2005, a team led by Carey Lisse of the Johns Hopkins Applied Physics Laboratory used NASA's Spitzer Space Telescope to gain a better understanding of these extraterrestrial bodies. The team found signatures of solid chemicals such as carbonates (chalk) and smectite (clay), as well as metal sulfides and carbon-containing molecules.
Scientists were surprised by the presence of clay and carbonates since they usually require liquid water to form, an element not usually found where comets are formed.
Scientists maintain that the study of comets doesn't end with Tempel 1 and that more complex missions that include robotic landing spacecraft and other technology are needed. Their findings appeared last week on the Science Express website.
China plans to invest $175 billion to curb water and air pollution over the next five years, state media said on Tuesday.
According to the official Xinhua news agency, the money would help build sewage treatment plants in 10 river valleys to dispose of wastewater discharged by urban areas. Part of the funds would also be used to reduce sulphur dioxide and dust in major cities.
China is home to 20 of the world's 30 most smog-choked cities. The country has been struggling to curb its environmental degradation, the product of more than two decades of near-double-digit annual growth. Its pollution woes became a subject of international concern last November when a toxic spill poisoned the Songhua river, a source of drinking water for millions.
The mammals who make the longest overland migration in the continental United States might disappear from Yellowstone and Grand Teton national parks, according to a study in the latest issue of the journal Biology Letters.
A herd of pronghorn, which for more than 6,000 years have journeyed at least 400 miles between their calving and wintering grounds, is being squeezed out of its migration routes by development and human disturbance outside the parks. Scientists from the Wildlife Conservation Society and the National Park Service found that six of the pronghorns' eight migration corridors in and out of the Yellowstone ecosystem have disappeared, and the animals must now pass through bottlenecks that are not much wider than a football field.
"It's amazing that this marathon migration persists in a nation of almost 300 million people," said lead author Joel Berger, a researcher at the Wildlife Conservation Society. "At the same time, the migration is in real trouble and needs immediate recognition and protection."