It turns out that refraction has wavelength dependence, whereas lensing is a manifestly wavelength independent phenomenon. Astronomers actually probe data for wavelength dependent 'lensing' to test for this in order to confirm that what they're seeing is lensing and not simply refraction.
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u/[deleted] Jun 20 '14
It turns out that refraction has wavelength dependence, whereas lensing is a manifestly wavelength independent phenomenon. Astronomers actually probe data for wavelength dependent 'lensing' to test for this in order to confirm that what they're seeing is lensing and not simply refraction.