Unexpected heat in oceans
In another worrying climate-change finding, scientists have discovered that oceans are warming far faster than previously thought. Climate researchers already know that the world’s seas absorb about 90 percent of the excess heat trapped on Earth by man-made greenhouse gas emissions. But the new study found that every year for the past 25 years, the oceans have taken in 13 zettajoules of heat energy—60 percent more than previously estimated and about 150 times the amount of energy humans produce as electricity annually. The researchers calculated ocean temperatures in a new way: Rather than taking readings from thermometers dotted around the planet, they examined carbon dioxide and oxygen levels in the atmosphere. When the world’s waters warm, they absorb less of these gases. If the findings are correct, the direct consequences of warming oceans—melting sea ice, rising sea levels, more powerful storms, coral reef destruction—will also happen faster than previously thought. Study leader Laure Resplandy, from Princeton University, says reversing climate change will now be even harder. “If we start cooling the atmosphere,” she tells BBC.com, “the heat stored in the ocean will eventually come back out.”
years earlier than a patient would typically be diagnosed, a new study suggests. Researchers trained a self-learning computer to recognize signs of the neurodegenerative disease in brain scans that are too subtle for a human to see, using more than 2,100 positron emission tomography scans from some 1,000 patients. The so-called deeplearning algorithm was then given a set of 40 brain scans it hadn’t studied before—it proved 100 percent accurate at detecting Alzheimer’s an average of more than six years prior to a patient’s final diagnosis. Co-author Jae Ho Sohn, from the University of California at San Francisco, cautioned that it was a small study, but said the results were promising nonetheless. “If we diagnose Alzheimer’s disease when all the symptoms have manifested, the brain volume loss is so significant that it’s too late to intervene,” he tells ScienceDaily.com. “If we can detect it earlier, that’s an opportunity for investigators to potentially find better ways to slow down or even halt the disease process.”
when Oumuamua accelerated after passing the sun. This could have been because the rock was expelling debris, much like a comet—but the researchers saw no visual evidence of a tail. One admittedly “exotic scenario” put forward by the Harvard team: Oumuamua may in fact be a “fully operational” alien probe, made from a strong, thin material that acts as a giant sail blown by solar radiation. Other astronomers described the theory as “fun and thought provoking,” but said there was no evidence to support it.