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Atomic interactions in everyday solids and liquids are so complex that some of these materials’ properties continue to elude physicists’ understanding. Solving the problems mathematically is beyond the capabilities of modern computers, so scientists at Princeton University have turned to an unusual branch of geometry instead.

Researchers led by Andrew Houck, a professor of electrical engineering, have built an electronic array on a microchip that simulates in a hyperbolic plane, a geometric surface in which space curves away from itself at every point. A hyperbolic plane is difficult to envision—the artist M.C. Escher used in many of his mind-bending pieces—but is perfect for answering questions about particle interactions and other challenging mathematical questions.

The research team used superconducting circuits to create a lattice that functions as a hyperbolic space. When the researchers introduce photons into the lattice, they can answer a wide range of difficult questions by observing the photons’ interactions in simulated hyperbolic space.

Scientists seeking to bring to Earth the fusion that powers the sun and stars must control the hot, charged plasma—the state of matter composed of free-floating electrons and atomic nuclei, or ions—that fuels fusion reactions. For scientists who confine the plasma in magnetic fields, a key task calls for mapping the shape of the fields, a process known as measuring the equilibrium, or stability, of the plasma. At the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), researchers have proposed a new measurement technique to avoid problems expected when mapping the fields on large and powerful future tokamaks, or magnetic fusion devices, that house the reactions.

Neutron bombardments

Such tokamaks, including ITER, the large international experiment under construction in France, will produce neutron bombardments that could damage the interior diagnostics now used to map the fields in current facilities. PPPL is therefore proposing use of an alternative diagnostic system that could operate in high-neutron environments.

The Allen Brain Explorer (beta) is an application that allows users to browse multimodal datasets in an annotated 3D spatial framework. This new application is an integrated web-based navigator, allowing users to explore the Allen Mouse Brain Connectivity Atlas projection data and Allen Reference Atlas (ARA) in a standardized coordinate space.

The Brain Explorer 2 software is a desktop application for viewing the Allen Mouse Brain Connectivity Atlas projection data and the Allen Mouse Brain Atlas gene expression data in the framework of the Allen Reference Atlas (ARA). This downloadable software will be discontinued in 2019, as improved functionality and new features will be available via the integrated web-based platform. Updates to this software will be discontinued after that time.

Japan’s Hayabusa2 probe made a “perfect” touchdown Thursday on a distant asteroid, collecting samples from beneath the surface in an unprecedented mission that could shed light on the origins of the solar system.

“We’ve collected a part of the solar system’s history,” project manager Yuichi Tsuda said at a jubilant press conference hours after the successful landing was confirmed.

“We have never gathered sub-surface material from a celestial body further away than the Moon,” he added.

Japanese spacecraft landed on the asteroid surface.


Hayabusa2 has collected a second sample from the asteroid’s surface. It could give us a unique insight into how the early solar system was formed.

The procedure: After a few hours of maneuvering, the spacecraft touched down on Ryugu’s surface at 9:15 p.m. US Eastern time yesterday. It then fired a bullet into the asteroid and collected some of the debris stirred up by the shot. The Japanese space agency JAXA tweeted that the mission had been a success and that the space probe had now left the surface again. It’s the second sampling mission after a similar one in April, and it required particularly careful preparations, because any problems could cause the materials gathered during the first operation to be lost. In April, Hayabusa2 had also fired a copper bomb into the asteroid’s surface to expose the rocks beneath, in anticipation of today’s mission.

Next steps: Hayabusa2 is scheduled to return to Earth at the end of this year, but before it does it has a final task: deploying a smaller rover called MINERVA-II2 later this summer. Its primary goal will be to explore in an environment where there is very little gravity.