SCI/TECH: What Color Is Mars, Really?, page 2

I reduced the panorama to something smaller for members on slower connections (120k) color_panorama_1200.jpg [Edited on 11-1-2004 by SkepticOverlord]

marsrovers.nasa.gov...

Spacecraft: Surface Operations: Instruments

Calibration Targets



When you adjust the color on your television set, you do so by picking something on the screen that you know should be a certain color (such as grass should be green) and you adjust your set accordingly. This is a form of calibration. You used the color of the grass as a reference point. Instruments that go to Mars also need to be calibrated so that scientists receive accurate information. There has to be a known reference -- a calibration target.

The rover's calibration targets are objects with known properties. For example, the Mössbauer Spectrometer´s calibration target is a thin slab of rock that is rich in magnetite. The APXS also uses another reference point on the inside of its dust doors. When these doors are closed, they protect the APXS sensor head from Martian dust and offer a calibration target on their interior surfaces. Mini-TES has an internal target located in the Pancam Mast Assembly as well as an external target on the deck of the rover.


The Pancam calibration target is, by far, the most unique the rover carries. It is in the shape of a sundial and is mounted on the rover deck. Pancam will image the sundial many times during the mission so that scientists can adjust the images they receive from Mars. They will use the colored blocks in the corners of the sundial to calibrate the color in images of the Martian landscape. Pictures of the shadows that are cast by the sundial's center post will allow scientists to properly adjust the brightness of each Pancam image. Children provided artwork for the sides of the base of the sundial.

humbabe.arc.nasa.gov...

Measurements also showed that the Martian atmosphere always had some fine dust suspended in it. The dust particles vary in size from smaller than visible wavelengths (0.4 - 0.7 micrometers) to as large as several tens of micrometers. (A micrometer is one-millionth of a meter, or about 0.00004 inches). Sky color measurements from Viking Lander 1 have been used with computer simulations of light scattering to estimate that the dust particles contained about 1% by volume of an iron oxide mineral known as magnetite (a black, opaque material). This mineral absorbs sunlight more effectively at blue wavelengths than at red wavelengths. Scattering (including absorption) of sunlight by the dust particles in the Martian atmosphere therefore accounts for the sky color. The scattering is more complicated than the simple Rayleigh case because the dust particles both reflect and absorb the sunlight, and because the presence of 'large' particles leads to more uniform scattering among the different wavelengths. If the dust did not absorb any sunlight, the Martian sky would appear whitish, since all wavelengths would be scattered to similar degree, much like sunlight scattered by clouds.

Here is a VERY large(4.7 MB) image of the rover. You can clearly see all the yellow, and blue parts that appear pink and grey in the panorama.

www-pao.ksc.nasa.gov...
_____________________________________________

Many other anomalies in the Spirit images.


www.truthhunters.com...

www.burlingtonnews.net...

www.enterprisemission.com...

[Edited on 11-1-2004 by AArchAngel]

[Edited on 11-1-2004 by AArchAngel]

Why does the sky look blue-ish in the image shown at the press conference and not in the ones at NASA's site?


marsrovers.jpl.nasa.gov...



Mars Rover science team member Matt Golombek, right, talks about mineral and chemical testing that will be done as mechanical systems engineer Chris Voorhees, left, and project scientist Joy Crisp listen at a news conference at Jet Propulsion Laboratory in Pasadena, Calif., Saturday, Jan. 10, 2004. NASA's Spirit, the first of two rovers to land on Mars, stood up to its full four-foot, nine-inch height and rested on its own six wheels for the first time. A recent panoramic image of the martian surfacemade by Spirit's cameras is projected at rear. (AP Photo/Reed Saxon)

apnews.myway.com...

[Edited on 11-1-2004 by AArchAngel]

[Edited on 11-1-2004 by AArchAngel]

Isn't the sky at its bluest near the sun at a sunset?

EDIT:

humbabe.arc.nasa.gov...

Note that the image of the true-color sunset shown at the top of the FAQ page (click below on FAQ) shows a red sunset sky. The sun, however, is surrounded by a blue halo. Why? The dust in the atmosphere absorbs blue light, giving the sky its red color, but it also scatters some of the blue light into the area just around the Sun because of its size. The blue color only becomes apparent near sunrise and sunset, when the light has to pass through the largest amount of dust.

(quote is from this page humbabe.arc.nasa.gov... )

[Edited on 11-1-2004 by Kano]

Originally posted by DaRAGE
he only reason our atmosphere lokos blue is because the Earth is covered with something like 70% Ocean/water.

That's why we have our blue atmosphere.
You find an ocean of water on mars, then i might accept a more atmosphere theory.

Actually, the blue color of the Earth's sky is the consequence of sun light being scattered by air and small particules in the atmosphere. The Rayleigh law explains why.

Here is a quick link I found with google. They say that on very a clear day, Mars sky would appear blue.
humbabe.arc.nasa.gov...

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