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It was suggested that there is a black hole in the center of the Milky Way, called Sagittarius A. The whole region is heavily obscured by dust, although some very long wavelengths can break through.

Since black hole is so close and so massive, is there any chance of seeing the gravitational lensing in any wavelength?

Which wavelengths are more affected by gravitational lensing, long or short?

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    $\begingroup$ Here's a gallery of Sag A* at a variety of wavelengths, but there doesn't appear to be any lensing effects there. $\endgroup$ – Kyle Kanos Oct 1 '15 at 12:21
  • $\begingroup$ Its such a pity that there is very little lensing, because we would be able to see far into the universe by using it. $\endgroup$ – COROVICD Oct 1 '15 at 12:45
  • $\begingroup$ Well we have seen gravitational lensing elsewhere, but it doesn't give us the ability to see far into the universe, I believe it's still within the observable universe. $\endgroup$ – Kyle Kanos Oct 1 '15 at 12:49
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Gravitational lensing is a consequence of a distortion of space-time by the presence of a (large) mass. Every kind of light (regardless of wavelength) thinks it is traveling in a straight line in this distorted space - therefore gravitational lensing will equally affect all wavelengths.

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have a look at the paper Observing gravitational lensing effects by Sgr A* with GRAVITY for a good review of this area.

Bearing in mind the opacity the region around Sagittarius A* our only hope of seeing lensing is if one of the orbiting stars passes behind the the black hole and is lensed, but the expected deflection of the light is too small to be measured by the kit we currently have available. However, as the paper describes, we expect the GRAVITY telescope to be accurate enough to detect the lensing.

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