by aichip » Mon Oct 24, 2005 9:51 pm
It only takes a moment to see that the image, at 512 pixels across and 3 cm total span, is showing us a lot of particles that are jreally stretching the limit for sand. In fact, those grains are mostly classified as fine gravel - being 2-4 mm in diameter.
The most coarse sand is only up to 2mm in diameter, and many of these particles are much larger than that. Simple math shows that at 3 cm over 512 pixels, just over 17 pixels is a millimeter. So anything over 35 pixels in span, in any axis, is fine gravel and not sand.
Why is this important? Because we often accept without question what we are told, but in this case, it is clearly not so. We can do the math and prove that. And, at this size and taking the atmospheric drag into account, it would take a wind of hundreds of miles per hour to get these particles airborne. The fastest measured wind speed on Mars' surface was 74 mph by Viking.
It only takes a moment to see that the image, at 512 pixels across and 3 cm total span, is showing us a lot of particles that are jreally stretching the limit for sand. In fact, those grains are mostly classified as fine gravel - being 2-4 mm in diameter.
The most coarse sand is only up to 2mm in diameter, and many of these particles are much larger than that. Simple math shows that at 3 cm over 512 pixels, just over 17 pixels is a millimeter. So anything over 35 pixels in span, in any axis, is fine gravel and not sand.
Why is this important? Because we often accept without question what we are told, but in this case, it is clearly not so. We can do the math and prove that. And, at this size and taking the atmospheric drag into account, it would take a wind of hundreds of miles per hour to get these particles airborne. The fastest measured wind speed on Mars' surface was 74 mph by Viking.