Finally, NASA has its universe of images in one happy, searchable place


When the Internet came along in the 1990s, like a lot of government agencies, NASA kind of scratched its head and wondered what to make of all this freely shared information. But unlike a lot of other agencies, NASA had a trove of images, audio, and video the general public wanted to see. After all, this was the agency that had sent people to the Moon, taken photos of every planet in the Solar System, and launched the Hubble Space Telescope.

So each of the NASA field centers—there are 10 of them—began digitizing their photo archives and putting them online. Johnson Space Center in Houston, for example, had thousands of images of space shuttle astronauts training and flying in space. Kennedy Space Center had launch

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Searching the Skies for Alien Laser Beams

In the last decade, the Keck Observatory in Hawaii, one of the world’s most powerful telescopes, has spent hours staring at the night sky in search of exoplanets and accumulating huge amounts of data about potential new worlds elsewhere in the Milky Way.

But maybe, Nate Tellis wondered, Keck might have picked up something else along the way. Somewhere in all that data, could there be a signal from an intelligent civilization trying to reach Earth?

Tellis is a scientist at the University of California at Berkeley, where, as his LinkedIn biography puts it, he spends his days “trawling” astronomy datasets for statistical deviations, trying to figure out whether they’re actually extraterrestrial pings. He searches particularly for laser light, powerful pulses of photons that could be … Read the rest

Solar energy has plunged in price—where does it go from here?

Enlarge (credit: Brookhaven National Lab)

In the year 2000, the entire world had roughly four Gigawatts of solar power capacity installed, and it didn’t seem to be going anywhere fast. In 2002, the International Energy Agency forecast suggested that, by 2020, global solar capacity would still be hovering at around 10GW, and still barely register on the global energy markets.

How things change. Over the 15 years that followed, solar energy capacity expanded by 5,700 percent, reaching 227GW. The International Energy Agency revised its solar estimates upwards three times over that span, but its most recent estimate—over 400GW of installed capacity by 2020—is already falling behind the curve of solar’s growth. In 2015, the most recent year that numbers are available, 57GW worth of solar

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Hunting for Mexico’s mass graves with machine learning


Over the last decade, Mexican drug cartels have been fighting each other—and corrupt police and military units—for control of the lucrative drug trade, plunging the country into chaos. Outsiders might think of Mexico as sunny and tequila-soaked, but beyond the beach resorts of Cancun and Mazatlan there hides a grimmer tale: levels of murder, rape, and kidnapping are hitting levels rarely seen outside hotspots in Africa, Asia, and South America.

So grim the tale, when 43 college students went missing in Mexico’s southern state of Guerrero in 2014, investigators found 129 other bodies in 60 fosas clandestinas (mass graves) before stumbling on badly burned remains in a mass grave they think might—possibly, maybe—contain what’s left of the missing students. Mexico’s attorney general says the local

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Natural gas is leaking from city pipes, but spotting leaks is getting easier.

(credit: Steve Harwood)

Researchers from Colorado State University have been working with Google Street View to map pervasive natural-gas leaks. These leaks come from pipes that can be buried three-to-four feet below city streets. Many of the millions of miles of piping that deliver natural gas locally to urban and suburban homes are decades old—in some cases piping can be more than a century old. Older pipes can be made of cast-iron or bare steel, and they are often corroded or broken in places. But because they’re buried and because natural gas is invisible, it’s hard to tell when a pipe is leaking underneath a sidewalk. Sometimes, digging up and replacing a pipe isn’t worthwhile for the utility that owns it if the leaks isn’t

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Mechanism of Vps4 hexamer function revealed by cryo-EM

Vps4 is a member of AAA+ ATPase (adenosine triphosphatase associated with diverse cellular activities) that operates as an oligomer to disassemble ESCRT-III (endosomal sorting complex required for transport III) filaments, thereby catalyzing the final step in multiple ESCRT-dependent membrane remodeling events. We used electron cryo-microscopy to visualize oligomers of a hydrolysis-deficient Vps4 (vacuolar protein sorting-associated protein 4) mutant in the presence of adenosine 5′-triphosphate (ATP). We show that Vps4 subunits assemble into an asymmetric hexameric ring following an approximate helical path that sequentially stacks substrate-binding loops along the central pore. The hexamer is observed to adopt an open or closed ring configuration facilitated by major conformational changes in a single subunit. The structural transition of the mobile Vps4 subunit results in the repositioning of its … Read the rest

Potential energy-driven spin manipulation via a controllable hydrogen ligand

Spin-bearing molecules can be stabilized on surfaces and in junctions with desirable properties, such as a net spin that can be adjusted by external stimuli. Using scanning probes, initial and final spin states can be deduced from topographic or spectroscopic data, but how the system transitions between these states is largely unknown. We address this question by manipulating the total spin of magnetic cobalt hydride complexes on a corrugated boron nitride surface with a hydrogen-functionalized scanning probe tip by simultaneously tracking force and conductance. When the additional hydrogen ligand is brought close to the cobalt monohydride, switching between a correlated S = 1/2 Kondo state, where host electrons screen the magnetic moment, and an S = 1 state with magnetocrystalline anisotropy is observed. We … Read the rest

SAVI: Synthetic apertures for long-range, subdiffraction-limited visible imaging using Fourier ptychography

Synthetic aperture radar is a well-known technique for improving resolution in radio imaging. Extending these synthetic aperture techniques to the visible light domain is not straightforward because optical receivers cannot measure phase information. We propose to use macroscopic Fourier ptychography (FP) as a practical means of creating a synthetic aperture for visible imaging to achieve subdiffraction-limited resolution. We demonstrate the first working prototype for macroscopic FP in a reflection imaging geometry that is capable of imaging optically rough objects. In addition, a novel image space denoising regularization is introduced during phase retrieval to reduce the effects of speckle and improve perceptual quality of the recovered high-resolution image. Our approach is validated experimentally where the resolution of various diffuse objects is improved sixfold.… Read the rest

CH3NH3PbI3 perovskites: Ferroelasticity revealed

Ferroelectricity has been proposed as a plausible mechanism to explain the high photovoltaic conversion efficiency in organic-inorganic perovskites; however, convincing experimental evidence in support of this hypothesis is still missing. Identifying and distinguishing ferroelectricity from other properties, such as piezoelectricity, ferroelasticity, etc., is typically nontrivial because these phenomena can coexist in many materials. In this work, a combination of microscopic and nanoscale techniques provides solid evidence for the existence of ferroelastic domains in both CH3NH3PbI3 polycrystalline films and single crystals in the pristine state and under applied stress. Experiments show that the configuration of CH3NH3PbI3 ferroelastic domains in single crystals and polycrystalline films can be controlled with applied stress, suggesting that strain engineering may be used … Read the rest