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| Definition of a parsec |
In her previous appearances on these pages (twenty-two times to date), Whetzel's become the poster child for a lack of attention to detail, poor proofreading skills, and rampant scientific illiteracy. This particular post is no different from her others, opening with prose like:
"The world's space programs continually change and evolve as technology .[sic] With those changes and the frequent updates in technology and scientific knowledge, the appeal of exploring space becomes more captivating."Yup, poor proofreading rears its ugly head in Joan's first sentence. But anyone can leave out a word or publish a typo; heck we think we might have done that just within the past year (although we regularly revisit and proofread). We've stopped by today, however, to comment on Whetzel's mathematical and scientific ignorance and not her editorial skills. Joan's topic is the light year and the parsec, which she introduces by sharing factoids like
"The light year (ly) measurement is used to calculate galactic and interstellar distances, at least for publications read by the general public. The scientific and astronomical communities prefer the term parsec (3.26 ly) a measurement that can be more easily obtained from and compared with data acquired through observation."
Would that Whetzel have mentioned what those measurements are or even where "parsec" got its name (see the image above)... but that's too science-y for her. No, instead, she wants to share big numbers -- and that's what she immediately does:"These larger measurements are more practical for computing the larger distances like the distance from our Sun to the nearest galaxy known as the Andromeda Galaxy. That distance would measure 21,000,000,000,000,000,000 km or 13048794989999998976 miles."We aren't sure why Joan chose not to place commas in her miles figure, but hey: that's her problem. What we found interesting was the difference in the number of significant digits: two for parsecs, twenty for miles. But wait, it gets better: Joan's very next sentence is, |
"That's the equivalent of 2,219701751e-12 light years or 6,805636508e-13 parsecs - both of these are much easier measurements with which to work."Ummm, there are a couple of problems with that sentence:
- The converted numbers actually 2,219,702 light years (2.21E+6) and 680,563 parsecs (6.8E+5).
- Why Joan thinks the exponents are negative is a complete mystery (for those unfamiliar with scientific notation, which apparently includes Whetzel, 1E-13 is a very small number, not a very large one).
- Why Joan mixed regular notation with scientific notation is completely beyond us. The number she cites – 2,21970175e-12 – is actually about 2.2E-4, or 0.00022 [note: Maybe she was using European notation, where a comma serves as the decimal point? Who knows?]
"...the speed of light can be defined as the speed [sic] that light travels in one year which equates to 299,792,458 miles per second"
 
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Besides the obvious circularity -- "the speed of light can be defined as the speed that light travels" -- and the gratuitous insertion of "in one year"; that's not the speed of light in miles per second. It's the speed of light in meters per second. We have to admit that we quit reading about then because, frankly, we were getting a collective headache. All we can say is that Whetzel's Dumbass of the Day total now stands at twenty-three... and we're pretty sure she isn't done yet. |
¹ The post has been deleted, and archive.org doesn't seem to have archived it. No loss...
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MM - ASTRONOMY
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