Physics & Astronomy News

<p>An artist’s conception of this unusual system, courtesy of Jonathan Holden/Disk Detective.</p>
Oldest Known Planet-Forming Disk Found
Scientists find a star surrounded by the oldest known circumstellar disk—a primordial ring of gas and dust that orbits around a young star and from which planets can form.
<p>Mars’ Valles Marineris canyon, pictured, spans as much as 600 kilometers across and delves as much as 8 kilometers deep. The image was created from over 100 images of Mars taken by Viking Orbiters in the 1970s.</p>

<p>Image: NASA</p>
New Technique May Help Detect Martian Life
A novel interpretation of Raman spectra will help the 2020 Mars rover select rocks to study for signs of life.

<p>Simplification to represent PT (Parity-Time) symmetry. Imagine a situation where two cars are traveling at the same speed at some instant in time, but car A is speeding up, and car B is slowing down. In order to go at the same speed, you can jump from one car to the other (Parity reversal) and back in time (Time reversal). The cars are like the light waves inside the fiber, the speed of the cars is a representation of the intensity of light and the jump symbolizes a phenomenon called tunneling. (Graphics modified from freepiks).</p>
Stable Propagation of Light in Nano-Photonic Fibers
New model on how to achieve a more stable propagation of light for future optical technologies was published.
<p>Regime of a single 1D wire subband filled</p>

<p>Credit: Dr Maria Moreno</p>
Quantum Effects Observed in ‘One-Dimensional’ Wires
Researchers have observed quantum effects in electrons by squeezing them into one-dimensional ‘quantum wires’ and observing the interactions between them.

Echoes of Black Holes Eating Stars Found
Astronomers now have new insights into tidal disruption flares, thanks to data from NASA's Wide-field Infrared Survey Explorer (WISE).
Individual Atoms Behavior Observed
For first time, researchers see individual atoms keep away from each other or bunch up as pairs.
Gaia’s First Sky Map
The first catalogue of more than a billion stars from ESA’s Gaia satellite was published – the largest all-sky survey of celestial objects to date.

Science Facts

It's Dusty Out There

by NASA Headquarters and

A speck from a comet? Displayed in a close-up under an electron microscope, this tiny bit ofcosmic dust may be our first sample of a passing comet. Less than one-tenth of a millimeter across, the particle is composed of millions ofeven tinier crystals.: Image Courtesy NASA There is no lower limit to the size of the solid particles that move around the Sun. Small asteroids grade downward into large meteoroids and then into smaller pebbles and so on down to the tiniest particles of dust. The most numerous particles are the smallest ones. A particle larger than a millimeter (about one twenty-fifth of an inch) in diameter is a relative rarity in space, but even smaller particles exist by the uncountable billions. There are enough of them to reflect sunlight in a faint glow, called the zodiacal light. Unlike planets and other large objects, dust particles are not permanent residents of the solar system. They spiral slowly inward toward the Sun. Over a million years or so, a typical particle will fall into the Sun, so that the current dust population must consist of fairly new arrivals, presumably shed from comets.

Because interplanetary dust particles may be actual samples of comets, strenuous efforts have been made to collect them. Many efforts failed because of the rarity of the particles and the contamination of collecting devices by terrestrial dust. Recently, however, extraterrestrial dust particles have been successfully trapped with collectors mounted on high-flying aircraft. The yield has been small so far: only about a hundred particles a few thousandths of a millimeter across. But recently developed instruments are so sensitive that even these tiny objects can be usefully studied. They are definitely extraterrestrial, for their chemical composition is like that of common meteorites (and not like that of the Earth), but they are fluffy, fragile objects, each particle a mosaic of millions of tiny crystals.

As we look ahead to the reappearance of Halley's Comet, we are continuing to collect and study the dust that may have been shed by comets in the past. Perhaps when Halley does appear, we may be able to do more than just look at it. We may be able to collect and analyze the very dust that it sheds as some of those tiny fragments drift down to our planet.

Constellation Sagittarius.
Introduction to Constellations

'Constellation' is the name we give to seeming patterns of starsin the night sky. 'Stella' is the Latin word for star and a constellation is a grouping of stars. In general, the stars in these groups ...
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The artist
White Dwarfs

White dwarfs are among the dimmest stars in the universe. Even so, they have commanded the attention of astronomers ever since the first white dwarf was observed by optical telescopes in the middle of ...
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An X-ray image of the Sirius star system located 8.6 light years from Earth.
Binary and Multiple Star Systems

Stars, like people, are seldom found in isolation. More than 80% of all stars are members of multiple star systems containing two or more stars. Exactly how these systems are formed is not well unders ...
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Science Quote

'The mathematician's patterns, like the painter's or the poets, must be beautiful; the ideas, like the colours or the words, must fit together in a harmonious way. Beauty is the first test: there is no permanent place in the world for ugly mathematics.'

Godfrey Hardy

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