by geoffrey.landis » Sun Jun 23, 2013 5:28 pm
A very misleading image and caption, I'm afraid.
This is a radar image. The dramatic reds and yelows color it have nothing to do with the temperature, or that it is a "once molten" surface. (In fact, all of the rocky planets have a "once molten" surface.) The color in the image is chosen for artistic effect.
JPL usually gives a red/orange color to the Venus surface. This is because the atmosphere scatters the spectrum, and most of the blue is gone by the time the light reaches the surface, leaving a yellow-orange light, so if you could actually see it, it would be illuminated with orange-yellow light. Here's a Russian image of the surface, showing the color and also the reconstruction of what it would look like in "white" light:
http://www.aerospaceweb.org/question/as ... urface.jpg
(I do have to note that the cameras were very poorly color calibrated, though.)
I don't have any idea why the most highly sloped surfaces in this radar reconstruction are colored as being yellower and brighter than more horizontal surfaces. It gives the visual impression of heat coming up from below, but this is inaccurate. (If anything, the lower altitudes should be redder and dimmer, not yellower and brighter, since there is less short wavelength light and less light total further down.)
The vertical in this image has been stretched, too, to make it look more dramatic.
Finally, the caption says that the "no" surface probes lasted longer than "a few minutes". In this case, the phrase "a few" should be translated as meaning "127".
A very misleading image and caption, I'm afraid.
This is a radar image. The dramatic reds and yelows color it have nothing to do with the temperature, or that it is a "once molten" surface. (In fact, all of the rocky planets have a "once molten" surface.) The color in the image is chosen for artistic effect.
JPL usually gives a red/orange color to the Venus surface. This is because the atmosphere scatters the spectrum, and most of the blue is gone by the time the light reaches the surface, leaving a yellow-orange light, so if you could actually see it, it would be illuminated with orange-yellow light. Here's a Russian image of the surface, showing the color and also the reconstruction of what it would look like in "white" light: http://www.aerospaceweb.org/question/astronomy/venus/surface.jpg
(I do have to note that the cameras were very poorly color calibrated, though.)
I don't have any idea why the most highly sloped surfaces in this radar reconstruction are colored as being yellower and brighter than more horizontal surfaces. It gives the visual impression of heat coming up from below, but this is inaccurate. (If anything, the lower altitudes should be redder and dimmer, not yellower and brighter, since there is less short wavelength light and less light total further down.)
The vertical in this image has been stretched, too, to make it look more dramatic.
Finally, the caption says that the "no" surface probes lasted longer than "a few minutes". In this case, the phrase "a few" should be translated as meaning "127".