Humanity has yet to reach the point of no return when it comes to catastrophic climate change, according to new calculations. If we content ourselves with the existing fossil-fuel infrastructure we can hold greenhouse gas concentrations below 450 parts per million in the atmosphere and limit warming to below 2 degrees Celsius above preindustrial levels--both common benchmarks for international efforts to avoid the worst impacts of ongoing climate change--according to a new analysis in the September 10 issue of Science . The bad news is we are adding more fossil-fuel infrastructure--oil-burning cars, coal-fired power plants, industrial factories consuming natural gas--every day. [More]

As children grow, brambles of short brain connections are gradually pruned down to longer, stronger neural pathways. Research has shown this trend to follow a fairly standard curve during normal development to adulthood, and scientists are now using this information to create predictive models of brain maturation. [More]

The first time you visit your boyfriend’s place, he no doubt tidies up, to give you the illusion that he doesn’t live like an animal. Well, animals, too, can use optical illusions to woo a mate. Take the bowerbird. [More]

Smart phones have become today's PCs, enabling mobile connection to the Internet, messaging and thousands of different apps. But for the smart phone to progress to an even higher level of sophistication and acceptance, it's going to need microprocessors, or chips, that can supply even more power, without draining the battery. No problem, says ARM Ltd. , a Cambridge, U.K. chip designer that specializes in mobile devices. [More]

NEW YORK--A company recycles a product, doing its part for the environment through reuse, only to be told it's worth more to destroy it. Welcome to the wonderful world of the carbon market, especially for a company that deals in refrigerants.

These gases, culprits in no less than two environmental crimes--the ozone hole and climate change--are required to efficiently cool your food and beverages. Yet, chlorofluorocarbons, to give them their proper name, are potent molecules that both exacerbate the blanket of greenhouse gases warming the world as well as chew up the stratospheric ozone layer protecting the planet's inhabitants from excess doses of ultraviolet sunlight.

In 1916, when British composer Gustav Holst finished his famous orchestral suite The Planets , the solar system was thought of as a relatively simple and unique place. Clyde Tombaugh, the American astronomer who would discover Pluto in 1930, was just a schoolboy when Holst's landmark composition was written, and the sum total of known planets was a tidy eight. [More]

Despite frequent reports that regular exercise benefits the adult brain, when it comes to schoolchildren, the concept of the dumb jock persists. The star quarterback stands in stark contrast to the math-team champion. After all, the two types require seemingly disparate talents: physical prowess versus intellect. Letting kids run around or throw a ball seems, at best, tangential to the real work of learning and, at worst, a distraction from it.

Parents, teachers and education policy makers have pitted athletics against academics even as they trumpet exercise as an antidote to obesity and poor health. From preschool onward, teachers encourage children to sit still rather than scamper. Many schools have cut back on physical education to make room for the three R’s. And when student scores on standardized tests become of primary importance to parents, politicians or other stakeholders in the education system, educators may feel pressured to direct students toward academic pursuits and away from athletic ones.

Humans have not set foot on the moon since Apollo 17 in 1972, but those missions are still producing surprises. An analysis of a collected rock has produced the first solid evidence for graphite, the form of carbon commonly used as pencil lead, in a lunar sample.

Andrew Steele, an astrobiologist at the Carnegie Institution of Washington, and his colleagues reported in the July 2 Science that they found dozens of graphite particles in a small, dark patch on the sample--a region just 0.1 square millimeter in area--as well as seven needle-shaped rolls of carbon called graphite whiskers. Other samples have yielded traces of the element implanted by the solar wind or locked up in carbide compounds, but discrete pockets of graphite of this relatively large size appear to be a unique find.

The Gulf of Mexico oil spill this year and subsequent cleanup efforts could drive the world's smallest sea horse into extinction, warns the Zoological Society of London and its marine conservation organization Project Seahorse . 

The tiny dwarf sea horse ( Hippocampus zosterae ), which grows to a maximum length of 2.5 centimeters, can be found only in the ocean waters off the Gulf Coast.

Some dinosaurs had feathers ; others had extendable claws or elaborate spikes . But a newly described species is the first to have been found with a distinctively humped back. [More]

Can the active ingredient in " magic mushrooms " help those with terminal cancer cope with their fate? That was the question asked by researchers, who published the results of their investigation September 6 in Archives of General Psychiatry . [More]

Editor's Note: Students from Dartmouth's Thayer School of Engineering are working in Tanzania to help improve sanitation and energy technologies in local villages. The student-led group , known as Humanitarian Engineering Leadership Projects (HELP), will file dispatches from the field during their trip. This is their ninth blog post for Scientific American. [More]

NEW YORK--There are any number of ways to make money trading, though some prefer the term gambling.

That's because the financial world is full of innovation these days--even in the wake of the Great Recession--which primarily means inventing new instruments to trade. One can still trade the mortgage-backed securities that helped derail the global economy or corporate debt repackaged as bonds. Enron helped pioneer the trade in "physical" electricity, actual power available for purchase on the grid and only physical in the sense that the infrastructure to transport it is more visible than an odorless, colorless greenhouse gas. Both are now lucrative markets, but certainly electricity, despite its physics, is more stable.

Until someone develops a common platform for building robots (think of the combination of Windows and Intel that has made PCs so accessible), the technology will remain elusive to the general public. At least that's the contention of Willow Garage, Inc., a Menlo Park, Calif. company that Wednesday made its PR2 personal robot available to the public . [More]

Some consumers buy organically grown foods because they believe the products are healthier, tastier and better for the environment. But is this assessment true? [More]

Point two laser beams so that they cross each other, and each goes through as if the other one did not exist. Light rays cannot interact with other light rays--or can they? With the help of a single atom, physicists have devised a system in which one light beam can turn another on or off. Such a light switch could serve as the basic component of futuristic optical quantum computers and may help open the way to a quantum version of the Internet, which would offer unbreakable data security.

The device makes use of a phenomenon called electromagnetically induced transparency, in which a laser beam can render opaque clouds of atoms temporarily transparent to a narrow wavelength of light. The cloud can then act as a switch for a second beam, either letting it through or blocking it. The result is similar to what happens with transistors in electronic circuits, where a voltage applied at one electrode controls whether current can flow between two other electrodes.

Inspired by human studies showing that avid coffee drinkers and smokers have a lower risk of Parkinson’s disease, scientists at the University of Washington decided to see what java and cigarettes do to fruit flies. [More]

By Eugenie Samuel Reich

Some time in the next decade, a U.S. [More]

By Ewen Callaway

Journal articles on hormone replacement therapy (HRT) ghostwritten by medical writers employed by the pharmaceutical industry serially understated the treatment's risks and promoted unapproved uses, according to an analysis of industry documents.

The analysis, published September 7 in the journal PLoS Medicine , is based on some 1,500 e-mails, contracts and other documents made public in July 2009, after The New York Times and PLoS Medicine successfully argued that their release would be in the public interest. [More]