LTE: Letters To The Editor
Professional Surveyor Magazine - July 2013
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How Much Does a Snowflake Weigh?
In the 2nd paragraph it is stated that, “One scientist likened 1 in 10 billion ...” to the “... change of mass of a super tanker from an added single snowflake.” A loaded super tanker weighs about 1/2 million kilotons. 50 snowflakes weigh about 1 gram. It would have been more correctly stated to say: “... from an added 2500 snowflakes,” but not nearly as dramatic.
While to some degree I share your incredulity in hearing this snowflake to super tanker comparison, perhaps you’ll want to address its source directly: Volker Liebig, Director of ESA’s Earth Observation Programmes. He made the statement during an hour-long press conference on March 31, 2011 at the Technische Universität München in Munich, Germany. The event where he gave that comparison was the Fourth International Gravity Field and Steady-State Ocean Circulation Explorer User Workshop, which had been organized by the European Space Agency.
Personally, I have never weighed either a snowflake or a super tanker. Sue Heavenrich [a science writer] seems to think that only the heaviest snowflakes weigh 0.02 grams but that most range in weight from 0.001 to 0.003 grams apiece.
Regardless of my skepticism as to any quantity (even when I’ve just measured it!), I loved Professor Liebig’s visualization given to help folks try and grasp what 1 in 10 billion might look like.
Field Notes Requirements
In the April issue, the author states, “Texas Natural Resource Code requires that all field notes will include State Plane Coordinates...” This is incorrect, per TNRC, Sec. 21.041. …. “The field notes of a survey of public land shall state (5) the State Plane Coordinates based on the Texas Coordinate System of 1927 or the Texas Coordinate System of 1983 values for the beginning point on the survey with appropriate reference to zone, mapping angle, grid distances, acreage and the N.G.S. Station to which the survey is tied.” Note that this refers to “a survey of public land.”
J Bryan Brennion, RPLS
Thank you for the clarification. You are right, I missed that specificity of the law. Fortunately, I believe my argument remains valid.
Teresa L. Smithson, PLS, MRICS
In the June issue feature, “The Schonstedt Legacy,” the text should read, “To date more than 450 [magnetic locators] have been deployed to such war-torn regions as central Asia, Africa, Southeast Asia, and the Balkans.”
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