If you have ever peered down a highway on a sunny day, you have probably seen the rising, wavelike ripples of heated air that distort the appearance of objects near the horizon. Similar disturbances in the atmosphere above us make stars twinkle as their light is distorted on the way down to Earth.
Although twinkling stars inspired a well-known nursery rhyme, the effect hampers astronomers attempts to study the heavens. Scientists at Lawrence Livermore National Laboratory are now building systems, known as a synthetic guide stars, to help astronomers accurately account for atmospheric distortions wherever they choose to point their telescopes. Pictures collected by large terrestrial telescopes equipped with such systems often exceed the quality of Hubble Space Telescope images.
Guide stars have long played an important role in correcting atmospheric distortion. Astronomers pick a bright, stable star near a region of the sky that they hope to study and monitor distortions in the guide star image to deduce the optical properties of the atmosphere. They then correct their images with adaptive optics, which distort telescope components to offset atmospherically induced errors. Generally, adaptive optics corrections involve warping light-collecting telescope mirrors with computer controlled motors that respond to changes in the guide star image.
James Riordon | EurekAlert
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21.07.2017 | American Institute of Physics
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21.07.2017 | National Institutes of Natural Sciences
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
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Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision
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