SA Forum is an invited essay from experts on topical issues in science and technology. Crowds love black-and-white animals. Perhaps the sharp contrast of light and dark conjures long-lost memories of how the world looks to people in their first weeks of life. Whatever the explanation, we’re often transfixed by the sight of zebras, orcas, giant pandas—and especially by the presence of white tigers. Just ask the Las Vegas entertainers Siegfried and Roy....
Much like a temperamental teenager, the sun has been acting up of late. As it approaches the peak of the 11-year solar activity cycle, predicted to occur next May, it has been displaying an increasing number of angry outbursts. These solar storms are technically called solar flares and are giant eruptions of radiation from the sun’s atmosphere that cause significant brightening of the area where they occur. Solar flares are sometimes followed by coronal mass ejections (CMEs), which spew charged and magnetized particles into space....
Key concepts Aerodynamics Drag Flight Forces Introduction Have you ever wondered how a parachute works—or which design features are most important in slowing someone’s descent? Parachutes come in many different shapes and sizes, but they work based on the same general principles. In this activity, you will test differently sized parachutes to see how changes in the size of the parachute affect flight. What do you think will work better: a bigger parachute or a smaller one?...
Kinetic-Energy Interceptors Feasibility: High Cost Estimates*: Ground-based kinetic-energy interceptor (adapted from existing U.S. ballistic missile defense program): $0–$3 billion Airborne kinetic-energy interceptor: $3 billion Apart from jamming the radio communications or attacking ground-control stations, probably the simplest way to disable a satellite is to launch a missile-borne payload and crash it into an orbital target. Medium-range ballistic missiles fielded by about a dozen nations can directly reach low Earth orbit (between 100 and 2,000 kilometers, or about 60 to 1,250 miles, high)....
We shall not cease from exploration And the end of all our exploring Will be to arrive where we started And know the place for the first time. –T. S. Eliot, Four Quartets: Little Gidding In an age of spacecraft and deep-sea submersibles, we take it for granted that humans are intrepid explorers. Yet from an evolutionary perspective, the propensity to colonize is one of the distinguishing characteristics of our kind: no other primate has ever ranged so far and wide....
Except perhaps for some remote island dwellers, most people have a natural tendency to view continents as fundamental, permanent and even characteristic features of Earth. One easily forgets that the worlds continental platforms amount only to scattered and isolated masses on a planet that is largely covered by water. But when viewed from space, the correct picture of Earth becomes immediately clear. It is a blue planet. From this perspective it seems quite extraordinary that over its long history Earth could manage to hold a small fraction of its surface always above the sea–enabling, among other things, human evolution to proceed on dry land....
“Heatwaves and droughts will very likely become more frequent in a warmer climate, and ecosystems will somehow respond,” says Philippe Ciais, a carbon-cycle researcher at the Laboratory of Climate and Environmental Sciences in Gif-sur-Yvette, France. “More storms will add an extra dimension to the problem.” The meeting was organized by the CARBO-Extreme project, a €3.3-million (US$4.5-million) collaboration of 27 groups from 12 countries, funded by the European Union. Attendees showed off an array of tools for uncovering how extreme events affect terrestrial carbon cycles, including numerical models, CO2 flux measurements and field experiments....
As the Zika outbreak that erupted in 2016 ebbed, health authorities warned that birth defects seen then might just be the tip of all the problems the virus caused when it infected fetuses. Now, as children exposed to the virus during pregnancy start to get older, researchers have started to tease out how common these secondary neurodevelopmental problems may be—and how they can occur even if babies appeared fine at birth....
MAY 1960 DEVELOPING INFANTS— “We expected that the shocked rats would be affected by their experience, and we looked for signs of emotional disorder when they reached adulthood. To our surprise it was the second control group—the rats we had not handled at all—that behaved in a peculiar manner. The behavior of the shocked rats could not be distinguished from that of the control group which had experienced the same handling but no electric shock....
For decades cancer specialists have offered patients three main therapies: surgery, chemotherapy and radiation. (Some cancer survivors pointedly refer to this harsh trinity as “slash, poison and burn.”) Over the years continual refinements in these admittedly blunt instruments have made the more severe side effects increasingly manageable. At the same time, effectiveness has improved markedly. And new, very targeted drugs (Herceptin and Gleevec) have become available for a few specific cancers....
A cosmic “traffic jam” may be critical to the formation of planets, a new study suggests. Stars are born from massive clouds of gas and dust that collapse under their own gravitational pull. During this process of gravitational collapse, material whirls faster and faster as it gets closer to the newborn star, in a speed-up is similar to how a figure skater spins faster with arms pulled inward than with them outstretched....
By Dan JonesAs diagnoses of autism spectrum disorder rise, the need for effective therapies has increased in urgency. Today, a paper in Nature describes two ways of reversing autism-like symptoms in a new mouse model of the condition.Autism spectrum disorder (ASD) affects up to 1 in 110 people. Although a few drugs have shown promise in mouse models, none is able to treat the core social deficits common to ASD in humans....
NASA’s much-awaited next-generation space telescope is finally ready to launch—just as soon as the weather cooperates. The James Webb Space Telescope, also known as JWST or Webb, has been in the works for decades. During a news conference held on Tuesday (Dec. 21), project officials confirmed that the observatory is ready to launch. However, within hours, NASA and its partners on the project announced that the long-delayed launch would be postponed by yet one more day, to Saturday (Dec....
By Andrew M. Seaman (Reuters Health) - At three years, improvement in type 2 diabetes is better after bariatric surgery than with lifestyle changes, a small new study suggests. “One of the most important things to take away is that there is durability of remission over time,” said Dr. Anita Courcoulas of the University of Pittsburgh Medical Center, who led the research. She and her colleagues studied 61 people, ages 25 to 55, with type 2 diabetes....
Tractor beams, a staple of science fiction, may be moving closer to science fact. In a paper published earlier this spring, physicists have proposed a structure that may enable light to pull objects. Normally, light pushes on objects, albeit weakly. In the field of optical manipulation optical tweezers employ this pushing force to move microscopic objects from atoms to bacteria. The ability to pull as well would increase the precision and scope of optical manipulation....
By Daniel Cressey of Nature magazineAhead of a key international meeting on tuna catches, an assessment is painting a bleak picture of the conservation status of some of the world’s most commercially valuable fish species.Bruce Collette, who studies ocean fish at the National Marine Fisheries Service Systematics Laboratory in Washington DC, and his colleagues conducted the first global assessment of the scrombids and billfish, groups of fish that include some of the species with the highest value as seafood, such as tuna and marlin, as well as staples such as mackerel....
A US space-weather satellite that is supposed to alert Earth to incoming solar storms has temporarily dropped offline five times in the year since it became operational. Its onboard computer may be experiencing hiccups caused unexpectedly by galactic cosmic rays. The Deep Space Climate Observatory (DSCOVR) went out of action most recently on October 11. In each case, it unexpectedly entered a ‘safe hold’ in which scientific data stopped flowing and engineers had to scramble to try to recover the spacecraft....
A self-driving car carrying a family of four on a rural two-lane highway spots a bouncing ball ahead. As the vehicle approaches a child runs out to retrieve the ball. Should the car risk its passengers’ lives by swerving to the side—where the edge of the road meets a steep cliff? Or should the car continue on its path, ensuring its passengers’ safety at the child’s expense? This scenario and many others pose moral and ethical dilemmas that carmakers, car buyers and regulators must address before vehicles should be given full autonomy, according to a study published Thursday in Science....
If Michelle Boyer had received her diagnosis of advanced and aggressive skin cancer in 2010 instead of 2013, she would almost certainly be dead by now. Melanoma, the most lethal form of skin malignancy, had spread from a mole on her back to her lungs, and she knew her prognosis was grim. But beginning in May 2013, the 29-year-old Seattle resident started a series of revolutionary treatments—some of which first became available in 2011—that prompted her immune system to identify, attack and shrink the tumors....
An influential group of US astronomers has laid out its vision for the biggest and best space telescope yet—a worthy successor to the much-loved Hubble Space Telescope that some say could cost US$10 billion or more. The proposed High-Definition Space Telescope (HDST) would have a mirror up to 12 metres across. That’s 5 times the width of the 2.4-metre Hubble, which revolutionized astronomy with its sharp views of the cosmos, and nearly twice as wide as the James Webb Space Telescope (JWST), which is being readied for its 2018 launch....
