S03E08: The Adhesive Duck Deficiency

Tonight’s episode of The Big Bang Theory begins with Howard, Raj, and Leonard camping out in anticipation of the Leonid meteor shower.   True to the writers’ comic timing, the Leonid meteor shower is upon us right now.   The number of meteors per minute will peak tonight (at 5:30A.M. California time, check your local listings.)

But the story really started much earlier than tonight’s opening scene in the desert….it begins November 13, 1833.   Late that night,  insomniac Americans were greeted with a sky filled with streaks of light.  This was not just a meteor shower, but a rare event with so many meteors that it is called a “meteor storm”, so named whenever the number of meteors exceeds 1000 per hour.  That night in 1833 the number of meteors exceeded 1000 per minute!

A traveling preacher,  Samuel Rogers, already awake at 3am to prepare for a journey westward, gave an eyewitness account:

Some of those wandering stars seemed as large as the full moon, or nearly so, and in some cases they appeared to dash at a rapid rate across the general course of the main body of meteors, leaving in their track a bluish light, which gathered into a thin cloud not unlike a puff of smoke from a tobacco-pipe. Some of the meteors were so bright that they were visible for some time after day had fairly dawned. Imagine large snowflakes drifting over your head, so near you that you can distinguish them, one from the other, and yet so thick in the air as to almost obscure the sky; then imagine each snowflake to be a meteor, leaving behind it a tail like a little comet; these meteors of all sizes, from that of a drop of water to that of a great star, having the size of the full moon in appearance: and you may then have some faint idea of this wonderful scene.

Similar stories were reported from across the country.  There was no Moon that night, yet the sky was bright enough to read by.

Theories proliferated quickly.   But it was an observation that explained the phenomenon, 33 years later.  In early 1866,  the U.S. Civil War had just ended a few months earlier, allowing the young naval paymaster Horace Tuttle to take up a post at the U.S. Naval Observatory.  There he returned quietly to his lifelong pursuit of comet hunting.  He soon  found a new one that passed directly through the Earth’s orbit, precisely where the Earth would be in mid-November.   (Since this is an American blog, I’ve  conveniently ignored the fact that Ernst Tempel, a European comet-hunter, already found it two weeks earlier.)    Tuttle’s measurements showed that every 33 years,  this comet, Comet 5P/Tempel-Tuttle, leaves its cold home in the asteroid belt beyond Mars, where it spends most of its time.  It speeds up, passes close to the Sun and returns.    But comets are basically dirty snowballs.  When Comet 5p/Tempel-Tuttle approaches the Sun, the heat of the Sun frees material from its icy core, leaving behind a debris field in space.

The debris orbits the Sun in the same path as the comet, in what is called a “meteoroid swarm”.  Raj tells us what happens next,  “The meteors don’t get here. The earth is moving into their path.” Every year, in mid-November, we Earthlings on our “Spaceship Earth” pass right through the debris field left behind by Comet 5p/Tempel-Tuttle.    The meteoroids in the debris are not stationary, they travel in their own orbit, following the comet’s trajectory.   The meeting of Earth and meteoroids is a classic T-bone traffic accident:


The cause of the Leonid meteor shower: (1) Comet 5P/Temple-Tuttle breaks up a little as it approaches the heat of the Sun, (2 & 3) The debris forms a meteoroid swarm, and (4) The Earth passes through the meteoriods forming the Leonid meteor shower. (Figure from Chaisson & McMillon: A Beginner's Guide to the Universe.)

The meteoroids are mostly tiny, like specks of sand.  Only when the enter the Earth’s atmosphere, at speeds around 40 miles per second into the air do they glow and burn up.  The bright light, the “meteor”, is due to the hot air and hot silicon and other metals in the meteoroid itself glowing from the heat.  Note the terms here:  The speck of sand is a “meteoroid”—it does not become a “meteor” until it is hot and glowing in the Earth’s atmosphere.   If a small rock-like object reaches the ground, that is then called a “meteorite”.  And despite what 5-year-olds might tell you, they are definitely not “falling stars”.

It does not take much air to cause the meteor to glow.   When you see the meteors, they are so high that the air there is less than one part in 100,000 as dense as the air we breathe.   We live in the lowest level of the atmosphere, where the densest air and weather is, called the “troposphere”.   Airplanes fly at around 35,000 feet at the top of the troposphere, a bit below the stratosphere.  A very high level of the atmosphere lies around 275,000 feet.  This layer, the “mesosphere” is where the meteors form. Scientists give it another name though:  “The Ignorosphere”.  That  is because it is barely studied.  It is too low to fly satellites in since the friction from the small amount of air would destroy their orbits.  But it is too high for flying scientific balloons, because there is not enough air to provide buoyancy.    A friend of mine studies it the only way to get there, by sending up sounding rockets.  But such rockets spend only about 5-10  minutes in that region before falling down, so we have precious little direct data.   (My friend was not very  happy during Season One when Sheldon took great offense at his sister calling him a rocket scientist.)

The Leonids storm of 1833 played a major role in our understanding that meteorites in space caused meteors.  Some suspected that meteors were an atmospheric phenomenon, and doubted there were  rocks or pebbles in space.  When two Northern farmers claimed that they saw a meteoroid  fall from their sky to their farm, Thomas Jefferson remarked:

I  would rather believe that two Yankee farmers lied than to believe that rocks fall from the sky.

Yet the meteors of the 1833 storm came from a spot on the sky that moved with the stars.   In fact, from the direction of the constellation Leo, hence the name  “Leonids”.   Since their point of origin did not stay fixed in the atmosphere, but rotated with the Earth,  that showed the meteors to be initiated by objects from space.  Don’t feel bad for Thomas Jefferson though, it was just one of many things he had wrong.

Astronomers predict that this year’s Leonids will put on an excellent show tonight.  Try to get out of the city and see them.  Camp overnight if you can.  Just watch out!  There will be science teachers  out there.

14 Responses to “S03E08: The Adhesive Duck Deficiency”

  1. Philip Says:

    Tonight’s episode was the first Big Bang Theory I have seen. Being a science geek, I really enjoyed the comedy. I don’t know if I will continue to watch the show because of one thing: the laugh track. The laugh track was so over done that it ruined the show for me.

    Could you please talk to the producers to tone it down or better yet, remove it all together? It is totally un-needed.

    • David Saltzberg Says:

      The show is actually taped in front of a live studio audience of over 200 people and it is their (uncoached) reaction you are hearing. I am not an expert, but I believe the audience reaction is an integral part of this comedy genre, e.g. the timing. I like to think of it as watching live theater.

    • Naomi Says:

      I had the same complaint. Luckily after about 3 or 4 episodes you become immune to the laugh track and don’t notice it. (I’m going to continue to call it a laugh track until the audio is adjusted to make the “live studio audience” sound less contrived.)

  2. Procyan Says:

    Why does the comet debris become distributed around the orbital path? In free fall should not the little bits keep pace with the parent body’s inertial reference frame and form a relatively dense cloud around the comet?

    Also I think you may have mixed up “roids” and “rites”

    Note the terms here: The speck of sand is a “meteorite”—it does not become a “meteor” until it is hot and glowing in the Earth’s atmosphere.

    Also I wish to endose Philips comment regarding laugh tracks. Paleese

    Great blog, thanks!

    • David Saltzberg Says:

      The term “meteorite” is reserved for debris found on the ground from a meteroid that passes through the atmosphere and survives to reach the ground.

      Why doesn’t the meteoroid exactly follow the comet…that is an excellent question. The meteroroid swarm largely follows the comet, but does eventually disperse due to several forces: 1) The small pieces of debris may resonantly interact with each other. 2) There are small frictional forces due to material in space, perhaps due to the comet itself, that affect the large comet differently than the small dust it leaves behind. 3) There is also the “Yarkovsky force” which is non-gravitational force due to radiation emission from the dust which can be anisotropic and different than the core of the comet. You can read about the roles of these forces in this paper.

      Thank you for your comments, which help sharpen the post.

    • David Saltzberg Says:

      Oops, when I went to edit, I see you were right and I had a typo between “roids” and “rites”. Thank you and I believe it is fixed now.

  3. summer Says:

    how long before the comet breaks up totally? or does that even happen?

    • David Saltzberg Says:

      Comets do eventually give up all their “volatile” materials, mostly ice, after many passes near the Sun. After that they will become just an ordinary rock (meteroid) orbiting the Sun. Different comets have different orbits and lifetimes. Some comets will be active for 1000’s of revolutions, or 10,000 to 100,000 years or so. Other comets go extinct much faster. There are many other ways for a comet to die. Sometimes it passes near a large body and is ejected from the solar system or placed into an orbit we never see again. Other times such interactions could cause it to break up into small pieces. A wonderful end of a comet was the collision of comet Shoemaker-Levy-9 with Jupiter in 1994. First it broke up, and then the fragments hit the surface of Jupiter in a fantastic display. There is a youtube video of the collision here: http://www.youtube.com/watch?v=7zNuT4dbdjU . We live in a violent universe.

  4. Heather Says:

    I very much enjoy Big Bang Theory and appreciate your contribution.
    I am not a scientist, so I understand that I may be wrong, but I think that Sheldon would have read Lothar Schafer’s In Search of Divine Reality. Especially considering that he was raised by a strongly Christian mother. Just a thought that I wanted to pass along.

  5. Heavens to Betsy Says:

    As a person who has attended a live taping, I would like to offer my opinion on the ‘laugh track’ topic.

    – most people who attend a taping are super-fans who are extremely excited to be there. Ergo, they genuinely DO find everything funny. I’m not one who typically laughs out loud, but I found myself experiencing a giggle-fit when I saw the Jiminy Conjecture taping and the guys were trying to get out of the closet. I could not stop laughing!

    – they shoot each scene a minimum of three times. Although the scenes and jokes can vary slightly between takes, we (the audience) typically hear the same jokes over and over. I will concede that the laughter during the first take is much louder and perhaps a bit more genuine than the laughter in subsequent take and so on. Therefore, I often assume that they use the laughter from the first take when editing.

    -Also worth noting is that oftentimes the audience laughs TOO loudly or TOO long and they drown out the next line (example: Fonzie’s entrance on Happy Days elicited a 20 second applause every week). The editors then can choose to use a laugh track to shorten the span of the laugh. Or they might have someone in the audience with a wild or crazy laugh and they don’t want to draw attention to it.

    – lastly, they have an uber-gazillion jillion (back me up this term David Saltzberg? ) microphones hanging above the audience trying to capture every laugh. We aren’t even allowed to eat hard candy because the sensitive microphones will pick up the sounds of plastic wrappers. If they were planning to add a laugh track anyway, I don’t think they’d go to all the trouble of hanging microphones everywhere.

    -they hire a comedian to entertain us for 5+ hours and keep us laughing. Again, why would they do that if they didn’t want our genuine laughter during the takes?

    In summary, I believe that the laughter that we hear on TBBT is mostly the real thing with a few artistic liberties taken here and there.

  6. SOP Notes » Sabbath June 26, 2010, 1:22 PM Says:

    […] On the falling of the stars.… All agree that the amount visable that night was HUGE! God knows how to do it big. […]

  7. Tradução: “S03E08: The Adhesive Duck Deficiency (A Deficiência do Pato Adesivo)” « The Big Blog Theory (em Português!) Says:

    […] feita a partir de texto extraído de The Big Blog Theory, de autoria de David Saltzberg, originalmente publicado em 16 de Novembro de […]

  8. April Says:

    This is so far my favorite episode. I watched it twice in a row the first time I saw it. Sheldon and Penny are just…perfect in this one.

  9. Traducción: “S03E08: The Adhesive Duck Deficiency” | The Big Blog Theory en Español Says:

    […] Artículo original por David Saltzberg […]

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