UPDATE 2014-01-15: The attached .zip file now contains a Mathcad Prime 3.0 worksheet (.mcdx) and—for those of you who are still using earlier verisions of Mathcad—an Adobe Acrobat printout (.pdf) of the worksheet so can see how it is put together.
Chicken Little is alive and well and hanging out on the Internet, in particular on YouTube. In 2012, in the midst of the phony Mayan Calendar/Nibiru/End of the World (AGAIN!!!) craze, lurked a tiny comet discovered by a Russian amateur astronomer named Leonid V. Elenin using the International Scientific Optical Network (ISON). Comet C/2010 X1 (Elenin) was small as comets go (estm. 2 km diameter) and not particulary exciting, but that didn't stop the doomsday crowd from assigning all manner of dread to this little chunk of ice and dust.
The purpose of this worksheet is to investigate and refute two spurious doomsday claims made about Comet Elenin. The first claim asserted that Comet Elenin was responsible for large earthquakes, specifically when the Earth, the comet, and another major solar system object were in alignment. Some variants of this claim asserted that Elenin was actually Nibiru (which doesn't exist) and was thus the size of a brown dwarf (which do exist, just not inside our solar system). I kid you not.
The second claim asserted that Comet Elenin was made of pure hydrogen cyanide (wrong), was going to impact the Earth (wrong), and that we were all going to die from the combined effects of the impact and cyanide poisoning (wrong). Comets do contain HCN, but only as a minor constituent. A variant of this claim was that Earth was instead going to pass through the comet's tail (wrong), which would contaminate our atmosphere (wrong)…and we were all going to die (wrong). Again, I kid you not.
This worksheet contains no magic, just facts, simple calculations, and analysis. Enjoy.