False Color

What is False Color?

Astronomers often observe planets, stars, and other objects in light wavelengths that are invisible to the human eye, such as infrared (wavelengths slightly longer than red light) or ultraviolet (slightly shorter than violet light). But, how do you show a human a picture taken in "invisible" light? Scientists assign different colors to different wavelengths, giving a false sense of color to the image. This technique allows them to easily see patterns and detail that would otherwise be hidden.

False color can also be used to enhance detail in regular pictures where there isn't a wide range of color-for example, in an aerial photo of a jungle, which may appear as a carpet of unbroken green. By assigning slightly different shades of visible green to radically different false colors like red and blue, scientists can make detail stand out. Or, the faint colors of a planetary picture can be boosted brighter, making it easier to pick out geological features.

The following images of asteroid Ida were taken by Galileo and are shown below in black and white, color, and a false color variation. In the false color image, the light blue areas are hypothesized to denote fresh (or younger terrain).

To learn more about the Electromagnetic Spectrum in general,
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For more details on False Color in general,
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Galileo Solid State Imaging Team Leader: Dr. Michael J. S. Belton

The SSI Education and Public Outreach webpages were originally created and managed by Matthew Fishburn and Elizabeth Alvarez with significant assistance from Kelly Bender, Ross Beyer, Detrick Branston, Stephanie Lyons, Eileen Ryan, and Nalin Samarasinha.

Last updated: September 17, 1999, by Matthew Fishburn

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