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A conceptual illustration of how POSYDON will work. (credit: BAE Systems)

A technology being developed under a Defense Advanced Research Projects Agency (DARPA) program could soon bring GPS-like navigation below the waves. The POSYDON program seeks to create a network of acoustic underwater beacons that act like GPS satellites—broadcasting a burst of data encoded into sound waves that underwater craft can use to get a fix on their location.

GPS uses radio signals from satellites carrying time and position data, allowing a receiver to passively pick up that data and calculate its position. But while GPS works well for ships, ground vehicles, and aircraft, the radio signal from GPS satellites doesn't penetrate very far below the ocean's surface. It’s a technical problem that submarines have dealt with since long before GPS was available. It has forced subs to come close to the surface and raise an antenna mast if crews want to figure out where they are.

During the Cold War, the US developed an incredibly accurate—and expensive—technology for helping submarines navigate the seas without surfacing. The solution was based on inertial sensors: gyroscopes measured acceleration and movement relative to the Earth in a fashion similar to the guidance systems used for ballistic missiles. Gyroscopes have since gotten a lot smaller, and the fundamental parts of inertial navigation are now part of most smartphones. But precise inertial systems are still very expensive and not easy to miniaturize. Really accurate inertial navigation has continued to be a problem for undersea drones.

(credit: NASA)

When the LIGO collaboration announced the first, unambiguous detection of the gravitational waves produced by a black hole merger, several of the researchers hinted that there would be further news emerging from the mass of data obtained during the first run of Advanced LIGO. That news has now arrived in the form of GW151226, a merger of two black holes roughly seven and 14 times the mass of our Sun.

Because of their small size, the black holes spent more time producing gravitational waves prior to their collision. In some ways, this gives us more information, but the lower intensity of the waves mean that there are much larger errors attached to most of its properties.

For physicists, GW151226 was a slightly delayed Christmas gift: it arrived at 3:40 in the morning UTC on December 26, 2015. LIGO has automated software systems that scan the data to look for events quickly enough to notify astronomers, who can turn conventional instruments in the direction of the detection. These systems realized there was something interesting going on 70 seconds after the gravitational waves hit Earth. The preliminary estimate was that random noise should produce an event like this only once every 1,000 years, so the astronomers (or, as the paper puts it, "electromagnetic partners") got sent an alert.

Pictures: A future Xbox One controller.

PC gamers may not be able to lord their preferred control scheme over their console brethren for much longer. Microsoft is promising that Xbox One developers will be able to easily integrate mouse and keyboard controls for their console games in a matter of months.

"Truthfully in our dev kit modes now keyboard works, mouse support is a little bit further away," Microsoft's Phil Spencer said in an interview with PCGamesN. "I say it because I know it’s not years away, it’s more like months away, but we don’t have an exact date yet."

Based on the quote, it's hard to say if that means full keyboard-and-mouse Xbox One games are just months away from market or if that's just when developers will be able to start work on adding such support for future games. Either way, it's a clear sign that Microsoft is speeding along in bridging gaming's decades-long PC-vs-console control scheme gap.

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LOS ANGELES—We first tried Oculus' hand-tracking Touch controller at E3 2015. At this year's show, we had another chance to use the company's crucial new control solution before its planned release later this year (We're hearing a possible November date through the grapevine but nothing reliable enough to be certain).

Overall, the latest prototype feels pretty similar to the controllers we first tried at last year's E3, but a few small refinements make it feel closer to a retail product. The triggers are especially easy to push now, requiring a very light touch compared to the thick, springy resistance on something like the HTC Vive's triggers. The thumbsticks seem improved with additional resistance and a rubberized grip.

Converted RGB Inovision image. (credit: Shelley Halpain, UC San Diego)

If one eye is temporarily or permanently damaged, the visual cortex will rewire itself, devoting more resources to the remaining functional eye. This change is reversible if binocular vision is restored. But until a recent study published in Science, we didn’t know how the brain manages to reallocate its resources. This new study shows that this change happens at the level of individual cells, which can shift their attention to eyes as needed.

The visual cortex functions by integrating information from the neurons that are wired to one of an animal’s two eyes. If you cover one eye up for long enough, there’s a shift where the other eye becomes dominant, and more of the visual cortex is devoted to the working eye. This occurs in many animals, including carnivores, primates, and rodents—in mice, this shift in dominance is reversible. What we haven't known is how it takes place. Does the visual cortex contain entire tissues devoted to different eyes that it repurposes, or do individual cells change their connections to follow different eyes?

The scientists used a technique called ratiometric calcium imaging, which allowed them to see excitatory changes in calcium concentration within the neurons, an indication that they're busy processing signals. The team used this to follow the sight-driven activity in the binocular visual cortex of adult mice.