Cover Story
Ground-Based Telescopes for the 21st Century

Patricia Daukantas
Astronomers are reaping the fruits of two decades of research in adaptive optics and inno-vative telescope design. Despite funding uncertainties, plans are moving forward to build a new generation of large optical and infrared telescopes... more>>
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Laser-Induced Fluorescence: Spectroscopy in the Sky
Chiao-Yao She and David A. Krueger
Scientists are using laser-induced fluorescence to assess temperature and wind in a largely
unstudied layer of the Earth’s atmosphere. Their results are crucial to our understanding
of solar-terrestrial relations and lay the groundwork for studies of global warming and
atmospheric turbulence. more>>
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Optical Atomic Clocks—from Dream to Reality
Long-Sheng Ma
Recent developments in atomic physics and laser technology, especially techniques for
laser cooling and the manipulation of atoms, have enabled the realization of so-called
Cesium fountain atomic clocks with relative accuracy approaching 4 x 10-16. more>>