March 18, 2018

10.04.10- Radio Astronomers Refine Celestial Grid.

Getting a good fix on positions both on the Earth and in the sky is tougher than it may sound. Tectonic plates move. The Moon raises tides under our feet. The whole planet orbits our Sun, which is itself flying about the galaxy and getting jostled by other stars, as the galaxies themselves are flying apart. Last year, however, astronomers at the National Science Foundationís Very Long Baseline Array of radio telescopes tackled the problem in a novel way. Using 35 radio telescopes worldwide, they monitored and measured the positions 243 quasars over a 24 hour period starting November 18th 2008. Quasars are ideal candidates for this kind of measurement because of their extreme distance. These high precession measurements break the old record for the most radio dishes employed, which stood at 23. The telescopes utilized a method known as Very Long Baseline Interferometry, which combines simultaneous signals collected over individually spaced telescopes to increase resolution power. Headquartered in Socorro, New Mexico, the VLAís data will not only refine astronomical measurements, but increase the accuracy of geophysical science as well.