Physics Today Daily Edition
MIT Technology Review: The Defense Advanced Research Projects Agency wanted to find a way to improve results from computer software when the input data is noisy. To do that DARPA worked with Joseph Bates of Singular Computing to develop a computer chip designed to produce close-but-incorrect answers to mathematical calculations: When asked to add 1 and 1, it came up with answers like 2.01 or 1.98. Bates tested the chip for a variety of functions and found that it performed very well on tasks such as high-resolution radar imaging, extracting 3D information from stereo photos, and deep learning. In a test of software that tracks objects in a video, the chip was 100 times as fast as a conventional chip and used less than 2% as much power.
IEEE Spectrum: Ian Burkhart broke his neck in 2010, which resulted in his becoming paralyzed from the fifth cervical vertebrae down. That meant he was only able to move his head, neck, and upper arms. Now, Chad Bouton of the Feinstein Institute for Medical Research in New York City and his colleagues have developed a neural implant that connects to an electronic sleeve on Burkhart's forearm and restores his control over one of his hands. The implant is an array of 96 electrodes that monitors electrical activity in the brain's motor cortex at a rate of 30 000 times per second. Burkhart had to train multiple times per week for 15 weeks so that the system could learn which signals corresponded with certain intended motions. Once the neuro-electrical signals were mapped to movements, the implant sent electrical pulses to the sleeve on Burkhart's forearm. The sleeve contained 130 noninvasive electrodes that stimulated the muscles necessary to move the fingers, hand, and wrist. When outfitted with the system, Burkhart was able to perform actions such as swiping a credit card and using the game controller to play Guitar Hero. Currently the system requires running a cable from the implant to the sleeve, but the researchers hope to be able to create a wireless communication system.
The Atlantic: On Wednesday Russian billionaire Yuri Milner, joined by Stephen Hawking, announced the newest of Milner's Breakthrough Initiatives: Starshot, a $100 million research program to build spacecraft capable of traveling to Alpha Centauri in 20 years. For comparison's sake, the current fastest-moving spacecraft is NASA's New Horizons, which would take tens of thousands of years to reach Alpha Centauri. And at just 4.4 light-years away, Alpha Centauri is the star system closest to Earth. The program involves deploying an array of lightweight disks fitted with photon thrusters for navigation, a power source, cameras, and a communication system. Propulsion would come from a ground-based laser shining onto one side of the disk, providing pulses of energy to accelerate each probe away from Earth. Milner thinks the technology for interstellar travel can be developed within his lifetime.
New York Times: Wildfires used to occur primarily during a single season of the year, but the drier winters and warmer springs of a changing climate have created conditions that are making wildfires a year-round hazard. The expansion of residential populations and inconsistent policies regarding fire prevention and combat have exacerbated the problem. Last year, a record 10.1 million acres burned in the US; the top five years for acres burned have all occurred in the past decade. The cost of fighting wildfires is growing too: Annual costs have reached $2 billion in the US. In February, Hawaii exhausted its federal funds for fighting fires four months before peak fire season began. Alaska's first fires began in February, a month when the state is usually covered in snow.
Nature: The Japan Aerospace Exploration Agency (JAXA) launched Akatsuki ("Dawn") in 2010 on a mission to Venus to study the planet's atmosphere and to look for signs of active geological processes. But a faulty engine valve caused the craft to sail by Venus and orbit the Sun. In December JAXA saved the mission by using the probe's secondary thrusters to finally achieve a Venus orbit. Now the team managing the spacecraft has presented the first images collected by Akatsuki's cameras. Taken 100 000 km from the planet, the images show details of the clouds in Venus's sulfurous atmosphere.
Gizmodo: In 2015 Jay Farihi of University College London requested a 1917 glass plate from the Carnegie Observatory for an article about planetary systems around white dwarfs. The plate contains an image of the spectrum of the white dwarf known as van Maanen's star. Photographic glass plates were used in the late 19th and early 20th centuries to study the chemical composition of stars. Farihi spotted an absorption line in the spectrum, indicating that something with a variety of heavy elements such as calcium, magnesium, and iron had blocked the star's light. White dwarfs having that sort of absorption pattern probably host rocky planetary systems. Farihi's find predates the next earliest known evidence of a probable exoplanet by more than 70 years.
Guardian: Last week, NASA's Kepler space telescope unexpectedly went into emergency mode, during which contact with the satellite became intermittent. Launched in 2009 and now situated roughly 120 million km from Earth, Kepler had a successful initial mission in which it detected nearly 5000 extrasolar planets by 2012. The following year, two of Kepler's four reaction wheels, which are used to stabilize the telescope, failed. NASA was able to repurpose the telescope for a mission dubbed K2. The unexpected loss of contact with Kepler occurred when the NASA team attempted to send commands to reorient the telescope just days before the start of a new survey. NASA was able to regain full communications with Kepler over the weekend and is now investigating what caused the emergency shutdown.
Scientific American: Two methods have been developed to determine the rate of the universe's expansion, called the Hubble constant. But they don't yield the same result. Researchers measuring the cosmic microwave background (CMB) radiation came up with a value of 67.3 ± 0.7 km/s/Mpc. Another group of researchers, who used the distance ladder method, now report a value of 73.02 ± 1.79 km/s/Mpc. The new study uses known cosmic distance markers, such as Cepheid variable stars and Type 1a supernovae, to calibrate measurements of galaxies' distances and redshift, or how quickly the galaxies are moving. That technique was used by Adam Riess of the Space Telescope Science Institute in Baltimore, Maryland, and his colleagues in the 1990s to prove that the universe's expansion was accelerating. Riess's team is also behind the latest study, which includes several new calibration points that yield a more precise value. Both the CMB and distance ladder research teams are continuing to examine their data and calculations to try to understand why the two systems still don't agree.