Changing features of the laser light likewise has a dramatic effect on the renderings. "Light from a pulsed laser produces a very fine-tooth line, with each line corresponding to a different wavelength," Gordon Walker, a retired University of British Columbia astrophysicist, told Discovery News. "With current technology, that pitch is too fine, all the lines are blended together." The new technique filters out some of the wavelengths, creating spaces that are closely calibrated to wavelengths in the electromagnetic spectrograph, the Rosetta stone for analyzing starlight. "Li and colleagues' brainchild is an optically filtered comb of evenly spaced frequency references, all derived from a single frequency source -- a pulsed laser," writes Walker in a related Nature article. "The idea is not new … nor is its application to astronomy. But [they] are the first to realize the concept in a way suitable for astronomical practice, in what could be a breakthrough in the precision of astronomical spectroscopy." The new system, which is expected to get is first test later this year, will use a laser comb to take a spectrum of a target star to establish a baseline. At various points in the future, additional spectra will be taken of the star to look for any shifts. Like the sound of a train approaching or receding into the distance, wavelengths of light shift as a star moves to and fro. Scientists are hopeful the new technique will reveal if there are any Earth-like planets doing the tugging. Related Links : |
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