Archive for May 25, 2012

NASA Scientist Figures Way To Weigh Space Rock

A scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., has accurately determined the mass of a nearby asteroid from millions of miles away. The celestial equivalent of “guess your weight” was achieved by Steve Chesley of JPL’s Near-Earth Object Program Office by utilizing data from three NASA assets – the Goldstone Solar System Radar in the California desert, the orbiting Spitzer Space telescope, and the NASA-sponsored Arecibo Observatory in Puerto Rico.

Incorporating extraordinarily precise observations collected by astronomer Michael Nolan at Arecibo Observatory in September 2011, Arecibo and Goldstone radar observations made in 1999 and 2005, and the gravitational effects of the sun, moon, planets and other asteroids, Chesley was able to calculate how far the asteroid deviated from its anticipated orbit. He found that 1999 RQ36 had deviated from the mathematical model by about 100 miles (160 kilometers)in the past 12 years. The only logical explanation for this orbital change was that the space rock itself was generating a minute propulsive force known in space rock circles as the Yarkovsky effect.

The Yarkovsky effect is named for the 19th-century Russian engineer who first proposed the idea that a small, rocky space object would, over long periods of time, be noticeably nudged in its orbit by the slight push created when it absorbs sunlight and then re-emits that energy as heat. The effect is hard to measure because it’s so infinitesimally small.

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OSIRIS-REx Scientists Measure Yarkovsky Effect

Scientists with the University of Arizona-led asteroid sample return mission OSIRIS-REx have measured the orbit of their destination asteroid, 1999 RQ36, with such accuracy they were able to directly determine the drift resulting from a subtle but important force called the Yarkovsky effect – the slight push created when the asteroid absorbs sunlight and re-emits that energy as heat.

The new orbit for the half-kilometer (one-third mile) diameter 1999 RQ36 is the most precise asteroid orbit ever obtained, OSIRIS-REx team member Steven Chesley of the NASA Jet Propulsion Laboratory said. He presented the findings May 19 at the Asteroids, Comets and Meteors 2012 meeting in Niigata, Japan.

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Subaru Telescope Pioneers The Use Of Adaptive Optics For Optical Observations

A research team from the University of Tokyo/Kavli IPMU, Ehime University, and the National Astronomical Observatory of Japan (NAOJ) has succeeded in conducting the first, full-scale scientific observationswith an adaptive optics (AO) system at optical wavelengths. The team connected the Kyoto Tridimensional Spectrograph II with the Subaru Telescope’s Adaptive Optics system and improved the spatial resolution of images by a factor of 2.5 over images taken without AO. Observations using Kyoto3DII coupled with AO 188 are likely to reveal the detailed structures and the formation processes of galaxies.

Unlike space telescopes, ground-based telescopes must deal with observational distortions from atmospheric turbulence that degrades the spatial resolution of images. Adaptive optics systems (Note 2) correct for the distortion of light in real time and facilitate the production of high-resolution images. However, the AO systems of large, ground-based telescopes have only been used with infrared instruments. The turbulence of Earth’s atmosphere distorts optical light more rapidly and significantly than infrared light. Therefore, the technical challenge of an AO system operating in optical wavelengths is to make faster and finer corrections of light distortion to obtain higher resolution images. Given the huge light-gathering capacity of the Subaru Telescope’s 8.2 m primary mirror and the high performance of its AO 188 system in the infrared, the research team hypothesized that this system could also yield high-resolution images at optical wavelengths.

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SETI Institute’s Jill Tarter Takes Issue With Stephen Hawking, MIB3, Prometheus And Battleship

Mountain View, California –The creative minds who fill movies and TV shows with angry aliens will soon be defending their vision of these extraterrestrial antagonists at SETIcon, a public event sponsored by the SETI Institute. The Institute is known for its science-based search for radio signals that would betray the existence of intelligent beings on distant worlds. SETIcon will take place June 22 through 24 in the heart of the Silicon Valley, and will feature a celebrity banquet honoring Jill Tarter who, for the last 35 years, has led the search for extraterrestrial intelligence at the SETI Institute.

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