Bent Starlight "At present, total solar eclipses are the only occasions when stars near the sun become visible to us, permitting measurement of the Einstein shift [of starlight's path by the Sun's gravity. T]he amount of this deflection becomes observationally quite inappreciable at distances of more than, say, six radii from the sun's center....
"In practice, these measurements are very difficult and uncertain, since eclipse observations are made under unusual circumstances.... The problem must be left to future eclipses or, perhaps, to observations from artificial satellites.... Owing to the observational difficulties, the Einstein shift will remain a moot problem for years to come."
The author of this article, Felix Schmeidler (Munich University Observatory), had himself tried to measure the Einstein shift at several eclipses. Only with the ESA's Hipparcos satellite (1989-1993) did astronomers confirm Albert Einstein's predicted shift to within one part in 1,000. The European Space Agency's Gaia satellite, launched last December (this issue, page 10), should do even better than Hipparcos.
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|Title Annotation:||75, 50 & 25 Years Ago; eclipse observations|
|Author:||Sinnott, Roger W.|
|Publication:||Sky & Telescope|
|Article Type:||Brief article|
|Date:||Apr 1, 2014|
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