Physics & Astronomy News

<p>Illustration of how light is transformed into ALP by the galaxy. Credits to Aurore Simonnet, Sonoma State University (for the active galaxy core image) and NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring (for the image of earth).</p>
Dark matter does not contain certain axion-like particles
Researches are getting closer to corner light dark-matter particle models. Observations can rule out some axion-like particles in the quest for the content of dark matter.
<p>Harmonic oscillator device - Credits: LENS. Florence, Italy /SEM, Trento, Italy</p>
The Universe, where space - time becomes discrete
It time continuous or discrete? Scientists propose a non-local union of relativity and quantum mechanics.

<p>ORNL researchers discovered that water in beryl displays some unique and unexpected characteristics. (Photo by Jeff Scovil)</p>
New state of water molecule discovered
Researchers have discovered a new state of water molecule using neutron scattering & computational modeling.
<p>A schematic of the CSU team’s device that demonstrates using light to create a spin current. A spin voltage drives spin-up and spin-down electrons to move in opposite directions, resulting in a pure spin current across a platinum layer.</p>
A brand-new way to produce electron spin currents
For the first time, scientists have used non-polarized light to produce what’s called a spin voltage – a unit of power produced from the quantum spinning of an individual electron.

Mars surface revealed in unprecedented detail
The surface of Mars – including the location of Beagle-2 – has been shown in unprecedented detail by scientists using a revolutionary image stacking and matching technique.
Team builds first quantum cascade laser on silicon
The advance may have applications that span from chemical bond spectroscopy and gas sensing, to astronomy and free-space communications.
A New Way To Get Electricity From Magnetism
By showing that a phenomenon dubbed the “inverse spin Hall effect” works in several organic semiconductors – including carbon-60 buckyballs - physicists changed magnetic “spin current” into electric current.

Science Facts

Big Fish

by Gene Mascoli and

Hubble Space Telescope in orbit as seen from the Space Shuttle.: Image Courtesy NASA, STScI The phrase 'big fish eat little fish' may hold true when it comes to planets and stars. Perhaps as many as 100 million of the sun-like stars in our galaxy harbor close-orbiting gas giant planets like Jupiter, or stillborn stars known as brown dwarfs, which are doomed to be gobbled up by their parent stars. Space Telescope Science Institute astronomer Mario Livio and postdoctoral fellow Lionel Siess did not directly observe the planets, because they had already been swallowed by their parent stars. But Livio did find significant telltale evidence that some giant stars once possessed giant planets that were then swallowed up. The devouring stars release excessive amounts of infrared light, spin rapidly, and are polluted with the element lithium.

About 4 to 8 percent of the stars in our galaxy display these characteristics, according to Livio and Siess. This is consistent with estimates of close orbiting giant planets, based on discoveries of extrasolar planets by radial velocity observations, which measure the amount of wobble in a star due to the gravitational tug of an unseen companion. An aging solar-type star will expand to a red giant and in the process engulf any close-orbiting planets. If the planets are the mass of Jupiter, or greater, they will have a profound effect on the red giant's evolution. First, according to Livio's calculations, such a star is bigger and brighter because it absorbs gravitational energy from the orbiting companion. This heats the star so that it puffs off expanding shells of dust, which radiate excessive amounts of infrared light.

The orbiting planet also transfers angular momentum to the star, causing it to 'spin up' to a much faster rate than it would normally have. Giant planets carry the lion's share of angular momentum in a stellar system. For example, Jupiter and Saturn contain 98 percent of the angular momentum in the solar system. Finally, a chemical tracer is the element lithium, which is normally destroyed inside stars. A newly devoured Jovian planet would provide a fresh supply of lithium to the star, and this shows up as an anomalous excess in the star's spectrum. In our solar system Jupiter is too far from the Sun to be swallowed up when the Sun expands to a red giant in about 5 billion years. However, detections of extrasolar planets do show that Jupiter-sized planets can orbit unexpectedly close to their parent stars. Some are even closer than Earth is to our Sun. These worlds are doomed to be eventually swallowed and incinerated.

An artist
Large Asteroid Zooms Safely Past Earth

A mountain-sized asteroid made its closest approach to Earth at 9:35 a.m. Eastern Time on Wednesday, Sept. 29, 2004. Although asteroid 4179 Toutatis came no closer than four times the distance between ...
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It's a Supernova

Scientists have discovered that one of the brightest gamma ray bursts on record is also a supernova. It's the first direct evidence linking these two types of explosions, both triggered by the death o ...
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Backyard Telescopes for New Planets. Is it Possible?

Fifteen years ago, the largest telescopes in the world had yet to locate a planet orbiting another star. Today telescopes no larger than those available in department stores are proving capable of spo ...
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Albert Einstein

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