Science | WPN World People News

Interstellar forecast for a nearby star: Raining comets! The comets are plunging into the star HD 172555, which resides 95 light-years from Earth. The comets were not seen directly around the star. Astronomers inferred their presence when they used NASA's Hubble Space Telescope to detect gas that is likely the vaporized remnants of their icy nuclei.
The presence of these doomed comets provides circumstantial evidence for "gravitational stirring" by an unseen Jupiter-size planet, where comets deflected by the massive object's gravity are catapulted into the star. These events also provide new insights into the past and present activity of comets in our solar system. It's a mechanism where infalling comets could have transported water to Earth and the other inner planets of our solar system. HD 172555 represents the third extrasolar system where astronomers have detected doomed, wayward comets. All of these systems are young, under 40 million years old.

Eerie mysteries in the universe can be betrayed by simple shadows. The wonder of a solar eclipse is produced by the moon's shadow, and over 1,000 planets around other stars have been cataloged by the shadow they cast when passing in front of their parent star. Astronomers were surprised to see a huge shadow sweeping across a disk of dust and gas encircling a nearby, young star. They have a bird's-eye view of the disk, because it is tilted face-on to Earth, and the shadow sweeps around the disk like the hands moving around a clock. But, unlike the hands of a clock, the shadow takes 16 years to make one rotation.

In its two-dimensional form, graphene is thought to be the strongest of all known materials. But researchers until now have had a hard time translating that two-dimensional strength into useful three-dimensional materials.

Monster black holes sometimes lurk behind gas and dust, hiding from the gaze of most telescopes. But they give themselves away when material they feed on emits high-energy X-rays that NASA's NuSTAR (Nuclear Spectroscopic Telescope Array) mission can detect. That's how NuSTAR recently identified two gas-enshrouded supermassive black holes, located at the centers of nearby galaxies.

Researchers from the Faculty of Physics, the Lomonosov Moscow State University, have described structural peculiarities of micrometer size diamond crystals of needle- and thread-like shapes, and their interrelation with luminescence features and efficiency of field electron emission. The luminescence properties of such thread-like diamond crystals could be used in different types of sensors, quantum optical devices and also for creation of element base for quantum computers and in other areas of science and technology.

The schematic drawing showing that various factors (e.g., moisture, oxygen, light illumination, applied electric field, etc.) during the operation of MAPbI3 perovskite solar cells can generate iodine, which leads to degradation of solar cells.

Taking a deeper look at photonic sintering of silver nanoparticle films -- the use of intense pulsed light, or IPL, to rapidly fuse functional conductive nanoparticles -- scientists uncovered a relationship between film temperature and densification. Densification in IPL increases the density of a nanoparticle thin-film or pattern, with greater density leading to functional improvements such as greater electrical conductivity.

One of six mobile clinics provided by WHO to deliver health services to people fleeing violence in Aleppo, Syria.

A researcher prepares to use a laser scanning (lidar) unit to scan snow depth at the Arapahoe Ski Basin Ski area in Keystone, Colorado.