Health & Science
Taking a close-up of Saturn’s rings
Four centuries after Galileo peered through his telescope and discovered the rings of Saturn, astronomers are anticipating their closest glimpse yet of those enigmatic bands of dust, ice, and rock. NASA’s Cassini spacecraft, which has been collecting data on Saturn and its many moons for 12 years, will use its remaining fuel to make daring dives through the gas giant’s ring system, which scientists hope will provide clues on how and when it formed. To start things off, the spacecraft will make a series of orbits around the planet’s outermost ring, plunging from Saturn’s north pole at a staggering speed of about 76,000 mph. Four months later, Cassini will begin the final phase of its epic mission, swooping in to make 22 passes through the gap between Saturn and its innermost ring. The orbiter will “graze” as it crosses the ring plane, sampling particles and gases that could provide clues about Saturn’s gravitational and magnetic fields. “We are going to try to understand what is going on in the interior of Saturn, and we are going to try to work out how long a day on Saturn is—it is a bit embarrassing, but we still don’t know,” Cassini astrophysicist Michele Dougherty of Imperial College London, tells TheGuardian.com. Cassini will fall into Saturn’s atmosphere in September 2017, bringing its historic mission to a fiery end.
Cracks in an Antarctic glacier
Warming ocean temperatures have caused a Texas-size glacier in West Antarctica to crack from the inside out––which could have dire consequences for Miami, New York, and other major coastal cities. After a 225-square-mile iceberg broke off the Pine Island Glacier last year, researchers combed satellite data and discovered that in 2013 a rift had emerged 20 miles inland. Rifts typically appear on the thin, brittle outer edges of an ice shelf; the fact that the Pine Island rift formed so far inland suggests warm waters are melting an ice crevasse from below, weakening the glacier’s center. Similar rifts have been discovered in Greenland, but never before has subsurface melting been observed within Antarctic ice. “It’s no longer a question of whether the West Antarctic Ice Sheet will melt, it’s a question of when,” Ian Howat, an Earthsciences professor at Ohio State University, tells LiveScience.com. Researchers warn the ice sheet could collapse within 100 years, causing a 10-foot rise in sea levels—and catastrophic coastal flooding.
HIV vaccine breakthrough?
Researchers have high hopes for the trial of a new HIV vaccine that attempts to exploit a weakness in the virus, which still claims more than 1 million lives a year. Known as HVTN 702, the study will be conducted at 15 sites across South Africa—where one in five people is infected with HIV—and include 5,400 sexually active men and women between 18 and 35. Each volunteer will receive five injections of the vaccine or a placebo over the course of 12 months and undergo monitoring for another two years. The vaccine is actually a reformulated version of a drug tested four years ago on 16,000 people in Thailand. That vaccine proved only 31 percent effective and wore off after a few years, but the trial revealed a previously unknown vulnerability in the resilient virus. Now the drug has been revamped to target that chink in HIV’s armor. Even if the new vaccine is only 50 percent effective, the Associated Press reports, it could significantly reduce the disease in areas with high rates of HIV infection. “Deployed alongside our current armory of proven HIV prevention tools,” says Anthony Fauci of the National Institute of Allergy and Infectious Diseases, “a safe and effective vaccine could be the final nail in the coffin for HIV.”
What dogs remember
It’s no secret that dogs can recall sensory cues, like someone’s scent or the jangling of a leash at walk time. But episodic memory— the ability to relive mentally a past experience—was thought to be uniquely human. A new study suggests, however, that dogs possess a similar skill and may recall events much as people do. Researchers in Budapest tested the memory of 17 dogs by having them imitate unfamiliar actions previously performed by their owners, reports NPR .com. For example, dogs would watch people tap an open umbrella that was resting on the ground. Then they were led away and told to lie down on a mat. An hour later, the animals were commanded to “Do it,” and in most cases they recalled and mimicked their owners’ actions, walking up to the umbrella and tapping it with a paw. “If you ask a dog to imitate an action that was demonstrated some time ago, then it is something like asking, “Do you remember what your owner did?’” says study author Claudia Fugazza. Granted, there may be limits to canine memory. When people recall experiences they usually imagine themselves in past events, a degree of self-awareness dogs probably lack.
Health scare of the week
Weed linked to Alzheimer’s
Proponents of legalizing marijuana have long argued the drug is safe for recreational use, but new research suggests long-term indulgence may reduce blood flow to the brain and increase the risk for Alzheimer’s disease. Using imaging technology that evaluates blood flow and cerebral activity— single photon emission computed tomography—researchers studied the brains of about 1,000 current or former marijuana smokers and those of 100 people who never touched the drug. They discovered that weed users had less blood flow to nearly every part of their brains. The effect was most pronounced in the hippocampus—the area responsible for learning and memory and the first affected by Alzheimer’s. “Our research demonstrates that marijuana can have significant negative effects on brain function,” study author Daniel Amen tells MedicalNewsToday.com. “The media has given the general impression that marijuana is a safe recreational drug. This research directly challenges that notion.”