Sojourner Found Spherules Years Ago
Images show thousands of spherules as well as coral
It may come as no surprise that an earlier rover found evidence of past aquatic life on Mars. By reviewing some of the images from Pathfinder and Sojourner, I have located both "blueberries" and coral. It even seems that some researchers had pointed out the coral previously but had not been taken seriously. This raises some interesting questions about what criteria NASA uses to gauge the findings.
Let's start with some of the earliest images of the soil from Pathfinder. This image is made as Sojourner is rolling off the platform and onto the Martian soil.
| The first thing
to establish is the poor resolution of these images. Our present day
imagers are far better in terms of resolution. But Pathfinder and
Sojourner were monumental achievements just the same. They came
about due to budget restrictions and the need to make things smaller and
cheaper.
The bottom line is that they did the job and did it well. This picture was taken by Pathfinder and shows the soil in fair detail. Note the small rounded rocks in the image. These seem to be about the right size and shape for spherules. Are they? |
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| I have circled a
small number of the most obvious rounded rocks in red. I also had to
find a way to measure the size of the rocks and compare them to the
Opportunity and Spirit spherules.
To measure the spherules, I had to have some sort of scale or ruler. I located the drawings of the Sojourner and some technical details about it. They specify that the leading edge of the solar panel (lined in green) measures 389 mm. This was all I needed to know. By taking the endpoints of the green line segment in the image ( {217, 52} and {362, 89} ) I calculated the line segment length using Pythagoras' formula. |
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Once I had this figure in hand, I found that the line segment was 149.65 pixels long. Knowing that this represented 389 mm, I divided and determined that at this distance from the camera, a single pixel was about 2.6 mm in width.
Now I measured the circled spherules and found that they tended to be 7 to 8 pixels wide. This meant that they measured about 20 mm in diameter. This is a bit too large for most of the spherules found by the two MER, but still not outrageously so. It did not convince me that this was the same thing.
It would be far better to locate spherules that fell within the same size range as those found recently. Could I find a better resolution image to check? These had little detail in the range that I needed- one to two pixels across.
This is when I found this image.
This is an image taken by the Sojourner rover. It has much better resolution because its camera is far closer to the soil and can resolve much finer details. Now I needed a new yardstick to measure by and then I could determine the size of the small spherules in the image of the soil. And yes, look closely- they are indeed small spherules.
As it happens, the wheels are the key. By using the same technique above, I measured the wheels in the previous image and came up with a width of 84 mm (or 3.3 inches for the English measurement fans). Now I magnified the image and measured the track width and calculated that the resolution was now 1.3 mm per pixel- a two-fold improvement over the last image.
Armed with this figure, I went on to measure the width of some of the spherules in the image above and arrived at roughly three pixels per spherule. This translates to 5.2 mm, a precise match with the spherules found at Meridiani Planum and Gusev Crater. This is no coincidence. Now, while I have no color images to compare to these results, and therefore cannot absolutely verify them, the images are compelling in how they show hundreds of uniform sphere shaped rocks of the proper scale embedded in the soil.
To see the brain coral and other Pathfinder images, click here.