Neptune Is Much Less Blue Than Depictions

Long-time Slashdot readers necro81 writes: The popular vision of Neptune is azure blue. This comes mostly from the publicly released images from Voyager 2's flyby in 1989 — humanity's only visit to this icy giant at the edge of the solar system. But it turns out that view is a bit distorted — the result of color-enhancing choices made by NASA at the time. A new report from Oxford depicts Neptune's blue color as more muted, with a touch of green, not much different than Uranus. The truer-to-life view comes from re-analyzing the Voyager data, combined with ground-based observations going back decades. (Add'l links here, here, and here.)

This is nothing new: most publicity images released by space agencies — of planets, nebulae, or the surface of Mars — have undergone some color-enhancement for visual effect. (They'll also release 'true-color' images, which try to best mimic what the human eye would see.) Many images — such as those from the infrared-seeing JWST — need wholesale coloration of their otherwise invisible wavelengths. The new report is a good reminder, though, to remember that scientific cameras are pretty much always black and white; color images come from combining filters in various ways.

Also thanks to long-time Slashdot reader Geoffrey.landis for sharing the story.

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