First up was John Delaney, an imaging scientist at the National Gallery of Art in Washington, D.C., who took snapshots of the painting using hyperspectral infrared reflectography, a technique that involves shining light of different wavelengths on an object — some of which probe deeper than others. (sciencemag.org)
Grisms, also called grating prisms, are used to separate light of different wavelengths. (sciencedaily.com)
Subsequently, by measuring how dust in Orion's largest circumstellar disk scattered light of different wavelengths, the scientists calculated that typical particles in the disk are at least 5 micrometers across. (sciencemag.org)