Light-Deflection Test of General Relativity

夏皮罗教授的小组将完成对1987年实验的分析，该实验测量了由于太阳引力效应而导致的无线电波偏转。利用超长基线干涉测量技术，他们以每年太阳经过其中一个射电源前为中心，在两周的间隔内观察了两个射电源。通过将这些数据与一个模型进行拟合，该模型包含一个自由参数，可以对广义相对论预测的效应进行缩放，他们将以广义相对论预测的0.1%的标准误差来确定引力偏转。提高广义相对论为数不多的观测测试之一的准确性非常重要，不仅因为它是对目前公认的引力理论的测试，而且因为广义相对论引力在理解宇宙学、黑洞、类星体和其他大质量天体方面的作用。这个“光”偏转实验比以前的实验更先进，因为它使用了在三个相隔很远的无线电频段（2、8和23 GHz）记录的信号，允许对电离层和太阳日冕中无线电波的分散造成的观测误差进行更高精度的修正。

Professor Shapiro's group will complete the analysis of their 1987 experiment to measure the deflection of radio waves due to the gravitational effects of the Sun. Using the technique of very-long-baseline interferometry, they observed two radio sources over a two-week interval centered on the annual passage of the Sun in front of one of the sources. By fitting this data with a model that includes a free parameter scaling the effects predicted by general relativity, they will determine the gravitational deflection with a standard error of 0.1 percent of the magnitude predicted by general relativity. Improving the accuracy of one of the few observational tests of general relativity is important not only as a test of the currently accepted theory of gravity, but also due to the role of general relativistic gravitation in the understanding of cosmology, black holes, quasars, and other massive astronomical objects. This "light"-deflection experiment is an advance over earlier ones since it uses signals recorded in three widely-separated radio-frequency bands (2, 8, and 23 GHz), allowing for higher accuracy corrections for the observational errors contributed by the dispersion of radio waves in the ionosphere and the solar corona.