September 11, 2012
You may have already seen this magnificent photograph of Mars, taken by the mast camera on the Curiosity rover. Everyone has marveled at how much it looks like Earth, with its gravely surface and sandy dunes.
Here is a cool fact that you may not have heard about this photograph. If you were standing on Mars, these are not the colors that you would see in front of you. The dust in the planet’s atmosphere makes everything look very red, including this sandy dune.
The reason this photograph isn’t red is that NASA’s engineers are doing something called "white balancing" - adjusting the colors to make the scene look the way it would with the kind of light we have here on Earth. They do this to help out a particular bunch of Earthlings - the geologists who are studying the images with eyes that are trained to recognize rocks, minerals and other substances in more familiar light.
Posted by: Seymour Simon
