Month: July 2016

Lux, a xenon-based dark matter detector. (credit: Lawrence Berkeley Lab)

Today, the team behind one of the most sensitive dark matter detectors announced its full experimental run had failed to turn up any of the particles it was looking for. The LUX detector (Large Underground Xenon) is designed to pick up signs of weakly interacting massive particles, or WIMPs, when they engage in one of their rare interactions with normal matter. The null result doesn't rule out the existence of dark matter, but it limits its potential properties.

As their name implies, WIMPs don't interact with normal matter often, but sthey hould on occasion bump into an atom, imparting energy to it. LUX provides a tempting target in the form of 370kg of liquid xenon. The detector is flanked by photodetectors to pick up any stray photons from the interactions, as well as hardware that picks up any stray charges knocked loose.

The challenge is to determine which signals are caused by dark matter and which are the product of cosmic rays or the natural background of radioactive decays. To handle the former, the detector is located nearly 1.5km below the surface in South Dakota's Homestake Mine. It's also partly shielded from the radioactive decays of the surrounding rock by an enormous tank of ultra-pure water. Even so, the scientists behind it had to spend time carefully characterizing the background noise. The success of that effort meant that LUX ended up four times more sensitive than it was originally designed to be.

Facebook's Aquila drone takes off from its launch dolly. (credit: Facebook)

Facebook's Connectivity Lab announced today that the company has for the first time test-flown a full-scale version of Aquila, the solar-powered high-altitude drone that Facebook hopes to use to deliver Internet connectivity to the remotest populated corners of the Earth. The test flight took place June 28 but was only announced today by Facebook.

The low-altitude test flight was originally intended only as a 30-minute “functional check” flight. "It was so successful that we ended up flying Aquila for more than 90 minutes—three times longer than originally planned," wrote Jay Parikh, Facebook's vice president of infrastructure engineering, in a post to Facebook's Newsroom blog published today.

The initial test goals were simply to ensure that the huge Aquila drone—with a wingspan comparable to a Boeing 737 and mass more like an automobile—could even get airborne. To minimize its weight, Aquila doesn't have "traditional landing gear," according to Martin Gomez and Andy Cox of the Aquila team. "We attached the airplane to a dolly structure using four straps, then accelerated the dolly to takeoff speed. Once the autopilot sensed that the plane had reached the right speed, the straps were cut simultaneously by pyrotechnic cable cutters known as 'squibs.'"

(credit: Nature Video/Matthew F. Glasser, David C. Van Essen)

Despite the advances of modern medicine, the wrinkled, twisted expanse of the human noodle has been mostly an uncharted frontier, with sparse territories and regions staked off so far. In the past, scientists have merely cordoned off sections based on a single type of brain feature, such as cell structures, brain topography, or identified functions. But now, in a comprehensive analysis of 210 healthy brains published Wednesday in Nature, researchers have merged such data sets and drawn an inclusive map of the mind's provinces.

The newly inked atlas, hatched from the National Institutes of Health’s Human Connectome Project, more than doubles the identified realms of the human brain’s outer shell, the cerebral cortex. This is the dominant part of the human brain, responsible for our minds’ higher functions, such as language, consciousness, information processing, and problem solving. The map depicts 360 cortex areas or 180 symmetrical, paired regions in each hemisphere, of which 83 were known and 97 are new.

While the new map is still a first draft, to be adjusted and honed with more research, the study's authors are hopeful that the cerebral sketch may quicken the pace toward understanding how the mind’s hardware works. Plus, it may provide a guide for neurosurgeons’ scalpels and more detail for researchers examining how the primate brain has evolved.

(credit: Mike Mozart)

Verizon Wireless customers who have held on to unlimited data plans and use significantly more than 100GB a month will be disconnected from the network on August 31 unless they agree to move to limited data packages that require payment of overage fees.

Verizon stopped offering unlimited data to new smartphone customers a few years ago, but some customers have been able to hang on to the old plans instead of switching to ones with monthly data limits. Verizon has tried to convert the holdouts by raising the price $20 a month and occasionally throttling heavy users but stopped that practice after net neutrality rules took effect. Now Verizon is implementing a formal policy for disconnecting the heaviest users.

The news was reported by Droid Life yesterday, and Verizon confirmed the changes to Ars this morning.

Enlarge (credit: /u/TheZ1mb1nator)

Space flight sim Elite: Dangerous has been officially available on PC for about 19 months (and on Xbox One for about nine), but players have still explored only a vanishingly small fraction of the game’s 400,000,000 suns. Frontier Developments has repeatedly said that there are plenty of strange things out in the galaxy that no one has yet found—though one of those mysteries might soon be coming to a head.

Strange objects called "unknown artifacts" have been showing up in the game for months, all appearing as a rough sphere a bit more than 100 light years in diameter surrounding a particular star system: Merope. The artifacts would transmit strange messages to ships that got close enough to scan them. Sleuthy players eventually decoded the signals, revealing them to be encoded wireframe images of the players’ ships. The unknown artifacts also seemed to cause problems when collected by players—shutting down systems and even disabling entire space stations if sold on those stations’ black markets.

Call of the wild

Now, a second class of unknown objects, called "unknown probes," have recently been spotted. These appear to point at a particular planet in the Merope system, Merope 5C. Further, the probes exhibit some remarkable behavior when players scan them with system discovery scanners: