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    Category Physics

    Do stars fall quietly into black holes, or crash into something utterly unknown?

    May 31, 2017, Categories  Astronomy/Space, Physics

    This artist's impression shows a star crossing the event horizon of a supermassive black hole located in the center of a galaxy. The black hole is so large and massive that tidal effects on the star are negligible, and the star is swallowed whole. Mark A. Garlick/CfA

    This artist’s impression shows a star crossing the event horizon of a supermassive black hole located in the center of a galaxy. The black hole is so large and massive that tidal effects on the star are negligible, and the star is swallowed whole. Mark A. Garlick/CfA 

    Astronomers at The University of Texas at Austin and Harvard University have put a basic principle of black holes to the test, showing that matter completely vanishes when pulled in. Their results constitute another successful test for Albert Einstein’s General Theory of Relativity. Most scientists agree that black holes, cosmic entities of such great gravity that nothing can escape their grip, are surrounded by a so-called event horizon...
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    Harnessing Energy from Glass Walls

    May 30, 2017, Categories  Physics, Technology/Electronics, Chemistry/Nanotechnology

    1.Prototype of a semi-transparent perovskite solar cell with thermal-mirror functionality. Copyright : Korea Advanced Institute of Science and Technology (KAIST) 2. Thermal images are taken by an infrared camera to compare the heat rejection performance of automobile window film, semi-transparent solar cell and glass. Copyright : Korea Advanced Institute of Science and Technology (KAIST) 3. Typical solar cells today are made of crystalline silicon, which is difficult to make translucent. Copyright : Liu Fuyu / 123rf

    1.Prototype of a semi-transparent perovskite solar cell with thermal-mirror functionality.
    Copyright : Korea Advanced Institute of Science and Technology (KAIST)
    2. Thermal images are taken by an infrared camera to compare the heat rejection performance of automobile window film, semi-transparent solar cell and glass.
    Copyright : Korea Advanced Institute of Science and Technology (KAIST)
    3. Typical solar cells today are made of crystalline silicon, which is difficult to make translucent.
    Copyright : Liu Fuyu / 123rf

    A Korean team has developed semi-transparent perovskite solar cells that could be great candidates for solar windows...

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    New Method improves Stability of Perovskite Quantum Dots

    May 29, 2017, Categories  Physics, Technology/Electronics, Chemistry/Nanotechnology

    Electron microscopy images of perovskite quantum dots embedded in the protective alumina matrix, and a photograph of the same film stable in water. Credit: © R. Buonsanti/EPFL

    Electron microscopy images of perovskite quantum dots embedded in the protective alumina matrix, and a photograph of the same film stable in water. Credit: © R. Buonsanti/EPFL

    EPFL scientists have built a new type of inorganic nanocomposite that makes perovskite quantum dot exceptionally stable against air exposure, sunlight, heat, and water. Quantum dots are nanometer-size, semiconducting materials whose tiny size gives them unique optical properties. Much effort has been put in building quantum dots from perovskites, which already show much promise for solar panels, LEDs and laser technologies.

    The new approach to stabilize the perovskite quantum dots was developed in the lab of Raffaella Buonsanti at EPFL Valais Wallis...

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    Neptune: Neutralizer-Free Plasma Propulsion

    May 29, 2017, Categories  Physics, Astronomy/Space

    This is an image of the Neptune thruster (right) with plasma expanding into a space simulation chamber. Credit: Dmytro Rafalskyi

    This is an image of the Neptune thruster (right) with plasma expanding into a space simulation chamber. Credit: Dmytro Rafalskyi

    Scientists study neutralizer-free plasma propulsion for spacecraft. Plasma propulsion is an important and efficient technology used to control spacecraft for Earth observation, communications and fundamental exploration of outer space. Plasma propulsion systems use electric power to ionize propellant gas and transform it into the 4th of matter, ie plasma. Electrically charged ions and electrons are accelerated in an exhaust beam to generate thrust and propel the spacecraft.

    The most established electric propulsion concepts, for example gridded-ion thrusters, accelerate and emit a larger number of positively charged particles than those with negative charge...

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