In honor of the Geminids

Last night marked the peak of the annual Geminid meteor shower, a light show courtesy of 3200 Phaethon, which has the orbit of a comet and the rock fraction of an asteroid and passes, at its closest approach, only 20 million kilometers (13 million miles) from the Sun (much closer than the planet Mercury).  In the last few days I’ve seen lots of posts and tweets drawing attention to the event and how to best view it, and a couple of them were accompanied by this very striking image:

fallingofthestars

That looks pretty spectacular!  Intrigued, I did a little digging on the origins of the image and came across this article by David W. Hughes, in which the author calls it “the world’s most famous meteor shower picture.”

It’s a woodcut depicting the Leonid meteor shower (not the Geminids) on November 13, 1833, based on an eyewitness account given by Joseph Harvey Waggoner fifty-four years later.  Having observed the event at the age of 13, Waggoner always remembered it as a moment of significance:  “To nothing do I look back with greater delight, and I never think of it without feelings of thankfulness that I was permitted to behold it.”  As an adult, he converted to the Seventh-day Adventist faith and became convinced that the 1833 meteor shower was the very same “falling of the stars” mentioned in the gospel of Mark as a sign of the return of the Savior (Mark 13:25).  He approached the Swiss artist Karl Jauslin to commission a drawing for him, and Adolf Völmy engraved the woodcut, which was circulated in the Adventist publication The Signs of the Times and later appeared in Bible Readings for the Home.

eden-cover

Waggoner published a book himself in 1888 called From Eden to Eden: A historic and prophetic study, a companion to “some of the most interesting portions of the Scriptures.”  Chapter 18 is devoted to “Signs of the Second Coming of Christ,” and the meteor shower features prominently:  “This was the last of the three signs given by our Saviour, and was altogether the most glorious and magnificent in its fulfillment, which was November 13, 1833.”

While the woodcut may seem exaggerated, contemporary accounts (some compiled in Hughes and others in Mark Littman’s The Heavens on Fire) seem to bear out Waggoner’s awed recollection of the event, both in the number of meteors observed and in their radiant pattern.  In his own words:

fast-falling-longer-1 fast-falling-longer-2

The origin of the meteors was unknown, but this display made it it clear to Waggoner and others that they were not atmospheric phenomena.  As the noted astronomer Denison Olmsted put it:  “This is no longer regarded as a terrestrial, but a celestial, phenomenon; and shooting stars are now to be no more viewed as casual productions of the upper regions of the atmosphere, but as visitants from other worlds, or other planetary voids.”  Inspired to collect information about the meteor shower, Olmsted presented his observations in two papers in The American Journal of Science and Arts, concluding that the meteors must have originated as a cloud of particles outside the atmosphere of the earth:

olmsted-cloudAn astronomer by the name of Hubert A. Newton contributed to this hypothesis by cataloguing other observations of meteor showers that seemed to occur at the same time of year, going back as far as A.D. 902 (recorded in Latin and Arabic sources).  From this data, he suggested a recurrence period of 33.25 years and predicted that the next big event would occur in 1866.  He was right!  And just a couple of months later, two independent astronomers (with fortuitously alliterative names) discovered comet Tempel-Tuttle, which has a period of 33.22 years (modern value).  Several observers pointed out the similarity between the orbit of the comet and the periodicity of the Leonids (described here).

newton-table

The relationship between Tempel-Tuttle and the Leonids remained obscured, however, by the variability of the meteor rates from year to year.  Some time later, in 1981, an astronomer at the Jet Propulsion Laboratory, Donald K. Yeomans, addressed this variability by mapping out the dust distribution surrounding the comet and its spatial relationship with Earth during closest approach.

yeomans-dust

One result of Yeomans’ work:  the dense dust around the comet lies mostly behind and outside of its orbit, suggesting that the solar wind and planetary perturbations control its distribution!

None of this has anything to do with the Geminids in particular, which are caused by a different orbiting body (3200 Phaethon), but I’ve found it pretty interesting, so here’s to meteor showers!

Posted in Extra Credit

Now with more monks!

Nollet’s famous demonstration of the Leyden Jar in 1746 for King Louis XV, in which he lined up 180 royal guardsmen and sent an electric shock through the human chain, was afterward repeated with even more people – this time with Carthusian monks.  Sources disagree on the actual number involved – some say 900 people joined the line, while others quote the number 900 in reference to the length of the human chain (“900 meters” or “more than one kilometer” are common descriptions that I’ve found).  Here’s Joseph Priestley’s account from his History and Present State of Electricity (1769):

Priestley says the line was “nine hundred toises” long and makes it clear that the monks made a much more impressive demonstration than the 180 guards.  But what is a toise, and how big is 900 of them?

The toise is a French unit of measure used in pre-revolutionary times that had its origins in the distance between the fingertips of a man with outstretched arms – like a wingspan.  It’s (approximately) equal to 1.949 meters, which means Nollet’s chain of monks spanned a distance of 1.75 km, or just over a mile (according to Priestley, at least, who himself cites the Phil. Trans. abridged, v. 10).

Most accounts also mention how impressed the onlookers (including the King) were to see everyone give “a sudden spring” once the circuit was completed.  The shock from the Leyden Jar passed through the bodies of the monks and the iron wires arranged between them, which (assuming a negligible deviation from the speed of light in a vacuum) should have taken < 0.00001 seconds.  No wonder they thought it was simultaneous!

Further reading:  from Priestley: The History and Present State of Electricity:  With Original Experiments;  more on the toise and other units of measure:  “History of Measurement”, “Units of Measurement in France before the French Revolution” (Wikipedia),

Posted in Extra Credit

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Ep. 1 Poster Version: Shock and Awe

For anyone who would like to read through the text or study the images at a more leisurely pace:

Shock and Awe (Adventures in Electricity)

Posted in TA Episodes

Shock and Awe – Episode 1!

See the previous post for sources and more information, and be sure to watch in HD!

Posted in TA Episodes

On Citing Things (+ Sources for Ep. 1)

In preparation for posting the first episode, I’ve compiled a list of all the sources (scholarly and not) that I used to put it together, and that got me thinking that I should probably clarify how I feel about sources and citing things and the internet in general.  In a nutshell:  it’s super important and not that hard and everyone should be doing more of it.  I’ve seen plenty of snappy videos on YouTube that explain a topic in a new and awesome way, but then don’t tell you how they know what they’re talking about – and that drives me crazy!  I don’t want you to take my word for anything.  I’m just a person with an interest, and I’ve put some time into reading up about the stuff that intrigues me.  I see no reason why I shouldn’t tell you where I got that information, and I’d be happy to be fact-checked too (well, not happy exactly, since I’ve really tried here, but you know what I mean).  So here goes:

Primary Sources:

Secondary Sources:

I’ve also tried really hard to only use images that are in the public domain (or failing that, to cite them properly), and here’s where I’ve found them:

  • Title page and figure from Nollet’s Essai
  • “Electric Boy”:  from “William Watson’s 1748 work”
  • Franklin & his kite:  Currier & Ives. “Franklin’s experiment, June 1752: Demonstrating the identity of lightning and electricity, from which he invented the lightning rod.” Prints and Photographs Division of the Library of Congress.
  • Nollet and the Guardsmen:  Engraving by H. Valentin in Louis Figuier, Les grandes Inventions
  • Electric Machine: Louis Figuier, Les merveilles de la science
  • Leyden jar cutaway
  • Electric Kiss
  • Effluent streams: 2nd ed. of Nollet’s Essai (also reprinted clearly in Heilbron, p.283)
  • Cartoons:  I’ve been extremely fortunate to have had the opportunity to work with Jorge Cham (the creator of PHD Comics) on a variety of projects, and he graciously agreed to illustrate a few of the concepts in this video with his catchy cartoons – including my new cartoon alter ego, which I love!

The portraits are all from Wikipedia:  NolletFranklin, Louis XV, Tesla, Maxwell, Fourier, Coulomb, Descartes, Newton

That’s it!  Stay tuned for the actual episode soon.

Posted in TA Episodes

Coming soon

Welcome to True Anomalies!  Stay tuned for the first episode (we’re heading to the eighteenth century, folks…), and read more about us in the meantime.

Posted in News