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Student’s Work Helps to Detect Near Earth Asteroids

November 21, 2011 Leave a comment

An asteroid impact with the earth can really ruin your day: just consider the dinosaurs. Most asteroids, also known as minor planets, orbit the sun beyond the planet Mars and present no danger, but there is a class of asteroids whose orbits cross the orbit of the earth. If one of these asteroids and the earth are at the same point in their orbits at the same time, a collision could occur. Called Near Earth Objects (NEOs), astronomers are interested in discovering as many of these as possible, and then tracking them in order to compute more accurate orbits. In this way, if a potential future collision were to be identified many years in advance, space probes could carry out steps to tweak the path of the NEO and deflect the collision. A program to track NEOs is being carried out at NOAO by Mark Trueblood with Robert Crawford (Rincon Ranch Observatory) and Larry Lebofsky (Planetary Science Institute). And last summer, a Beloit College student, Morgan Rehnberg, has developed a computer program (PhAst), available via the web, to help with this effort.

Asteroids move quickly across the sky, so in order to recover and track them, fast and accurate data reduction and analysis is essential. Unlike most of the data that astronomers work with, tracking a fast moving asteroid requires that the observer view multiple digital images obtained at the telescope by blinking between them, almost like a movie. In addition, accurate coordinates locating the NEO in the sky need to be computed. (Termed right ascension and declination, these are similar in concept to the latitude and longitude of a position on earth.) While there are many software packages that amateur and professional astronomers use (Maxim DL, Astrometrica) none did exactly what the group required. Seeing the need for better software but not having the time to devote to the task of writing it, Trueblood saw this as an ideal project for a summer student.

Full Story: http://www.noao.edu/news/2011/pr1107.php

Lightning Sprites Are Out of This World

November 21, 2011 Leave a comment

Only a few decades ago, scientists discovered the existence of “sprites” 30 to 55 miles above the surface of the Earth. They’re offshoots of electric discharges caused by lightning storms, and a valuable window into the composition of our atmosphere. Now researchers at Tel Aviv University say that sprites are not a phenomenon specific to our planet.

Jupiter and Saturn experience lightning storms with flashes 1,000 or more times more powerful than those on Earth, says Ph.D. student Daria Dubrovin. With her supervisors Prof. Colin Price of TAU’sDepartment of Geophysics and Planetary Sciences and Prof. Yoav Yair of the Open University of Israel, and collaborators Prof. Ute Ebert and Dr. Sander Nijdam from the Eindhoven Technical University in Holland, Dubrovin has re-created these planetary atmospheres in the lab to study the presence of sprites in space.

The color of these bursts of electricity indicate what kinds of molecules are present and may explain the presence of exotic compounds, while providing insight into the conductivity of distant planets’ atmospheres. This research, which was presented in October at the European Planetary Science Congress in France, could lead to a new understanding of electrical and chemical processes on Jupiter, Saturn, and Venus.

Full Story: http://www.aftau.org/site/News2?page=NewsArticle&id=15573