A test of general relativity using radio links with the Cassini spacecraft
A test of general relativity using radio links with the Cassini spacecraft
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DOI：
10.1038/nature01997
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发表时间：
2003-09-25
期刊：
影响因子：
64.8
通讯作者：
Tortora, P
中科院分区：
文献类型：
--
作者：
Bertotti, B;Iess, L;Tortora, P
根据广义相对论，光子会因任何质量产生的时空曲率而偏转和延迟（1-3）。弯曲和延迟正比于gamma+1，其中参数gamma在广义相对论中为1，但在牛顿引力模型中为零。伽马-1测量的是引力在多大程度上不是一个纯粹的几何效应，而是受到其他场的影响;这些场可能对早期宇宙产生了强烈的影响，但现在已经减弱，产生了微小但仍然可以检测到的影响。几个实验已经证实了对太阳产生的光子的偏转（4，5）和延迟（6）的预测的准确度接近0.1%。在这里，我们报告的无线电光子的频率偏移的测量和从卡西尼号航天器，因为他们通过附近的太阳。我们的结果，γ =1+（2.1+/-2.3 x10（-5）），与标准广义相对论的预测一致，其灵敏度接近理论上在某些宇宙学模型中预期的偏差水平（7，8）。
According to general relativity, photons are deflected and delayed by the curvature of space-time produced by any mass(1-3). The bending and delay are proportional to gamma+1, where the parameter gamma is unity in general relativity but zero in the newtonian model of gravity. The quantity gamma-1 measures the degree to which gravity is not a purely geometric effect and is affected by other fields; such fields may have strongly influenced the early Universe, but would have now weakened so as to produce tiny-but still detectable-effects. Several experiments have confirmed to an accuracy of similar to0.1% the predictions for the deflection(4,5) and delay(6) of photons produced by the Sun. Here we report a measurement of the frequency shift of radio photons to and from the Cassini spacecraft as they passed near the Sun. Our result, gamma=1+(2.1+/-2.3)x10(-5), agrees with the predictions of standard general relativity with a sensitivity that approaches the level at which, theoretically, deviations are expected in some cosmological models(7,8).