transilluminate

trans- +‎ illuminate

transilluminate (third-person singular simple present transilluminates, present participle transilluminating, simple past and past participle transilluminated)

1. To pass light easily through an object, body part, or liquid.
   • 2001, Oliver Sacks, Uncle Tungsten: Memories of a Chemical Boyhood

     Kirchoff and others went on to identify a score of other terrestrial elements in the sun, and now the Fraunhofer mystery — the hundreds of black lines in the solar spectrum — could be understood as the absorption spectra of these elements to the outermost layers of the sun, as they were transilluminated from within.