On the Subject of Comet Tails...

Does everyone remember the gorgeous appearance of the Hale-Bopp comet a few years ago?

Back in 1997, the night sky was made all the more beautiful when this stunning comet made its presence known. The comet itself is magnificent, but what people most notice is the gorgeous, colorful tail that sweeps away behind it. However, the comet's tail is the source of a common misconception that we will be exploring on today's FactRoulette!

Here on Earth, we're used to tails or wakes following behind an object as it moves forward. Note the direction of the trail of dust behind a vehicle as it travels down a dusty country road, or the wake left behind a ship or boat as it travels across the surface of a body of water.

The dirt kicked up by this bike follows behind the rider as he travels forward.

The wake follows behind the U.S.S. Enterprise as it sails the high seas.

However, comets are a little different. We all drew comets as children with the tail following behind it, just as we would expect. However, the truth is a little more complicated. Think of the previously-mentioned car driving on a dirt road. If it's a calm day, the dust follows directly behind the car in the direction of travel. However, if it's a very windy day, and the wind is blowing perpendicular to the direction of travel, the dust will appear to be coming off the car sideways. The same happens to comets.

"But," you ask, perplexed, "there's no air in space. How can there be wind?"

Not the wind we're used to here on Earth, of course. That would be impossible. No, the tail of a comet is formed by something else entirely: solar wind.

It is the radiation and heat from the local star that creates the tail, by melting gases and ice on the comet. Therefore, the tail always points away from the star, not necessarily in the direction the comet is coming from.

However, there is a small wrinkle in all of this. If you look closely at the picture of Hale-Bopp above you will notice that there is not merely one tail, but two. The large, white tail is indeed dust. This tail does in fact curve somewhat as the comet travels through space. It points in the direction away from the star as the solar wind "blows" the debris into space, but is "left behind" as the comet travels along its orbit.

The second, smaller tail is made up of gasses "blown" off the comet by the intense radiation of the star. This tail generally points directly away from the local star, as seen in the diagram below.

So, contrary to what one might expect, the tails you see coming off of a comet do not extend behind the comet, but rather away from the local star (our sun) as the comet is bombarded by the intense radiation and solar wind it puts out!


Photos:

"Comet Hale-Bopp 1995O1" by E. Kolmhofer, H. Raab; Johannes-Kepler-Observatory, Linz, Austria (http://www.sternwarte.at) - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Comet_Hale-Bopp_1995O1.jpg

"Motorbike rider mono". Licensed under GNU Free Documentation License 1.2 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Motorbike_rider_mono.jpg

"Enterprise Cruising" by DoD photo by Petty Officer 1st Class Todd Cichonowicz, U.S. Navy. (RELEASED) - Source. Licensed under Public domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Enterprise_Cruising.JPG

"Cometorbit". Licensed under Public domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Cometorbit.png

Walking Through Doorways and Its Effect on Our Memories

You know that feeling you get when you get up from whatever you're doing and walk to the kitchen, only to realize that you can't remember what it is you went into the kitchen for? That effect is what we're exploring in today's FactRoulette!

Studies have shown that human beings experience an odd effect that kicks in specifically when we walk through a doorway or other passage into a new room or environment. When we walk into a new room, experiment after experiment and as well as anecdotal evidence has shown that we frequently forget whatever was on our minds before doing so. But why does this happen?

Walking through doorways has a peculiar effect on the human brain.

The answer can be found in years of evolution. Our minds have evolved to be as efficient as possible when it comes to dealing with threats to our personal being. It turns out that our brains basically do a "hard re-set" to prepare ourselves for whatever dangers we may encounter in the new, unknown environment. Commonly, a lot of what is in our short-term memories is cleared to make way for our brains to deal with the current situation. Therefore, when we pass through a doorway or passage, years of evolution have taught our brains to be as prepared as possible. Whatever we were thinking before in the earlier environment is likely less important than any new information we might get from our new environment.

As Jeffrey M. Zacks, a psychology professor and director of The Dynamic Cognition Laboratory at Washington University in St. Louis put it, “When we walk from one room to another, information about people and objects that we were dealing with in the old room is less likely to be relevant, and it appears our memory machinery is optimized to take advantage of this, releasing that old information to make information about the new situation more accessible."

So the next time you get off the couch to get yourself a cold can of soda, make sure to keep the reason you went into the kitchen on your mind. I'm pretty sure the dangers posed by your refrigerator are not dire enough to worry about!

Now what did I come in here for again?

Source:

Through Doorways and Forgetfulness: Memory Researcher Receives Publicity, High Praise: http://psychology.nd.edu/news/35868-through-doorways-and-forgetfulness-memory-researcher-receives-publicity-high-praise/

How Dangerous are Sharks, Really?

This week is, to some, as sacred as a holy week in a church's liturgical calendar, or as treasured as the only two weeks of vacation that some get every year. Can you guess what I'm talking about?

That's right. It's SHARK WEEK on the Discovery Channel.

If you watch this annual event, you are likely to be bombarded by accounts of the terrifying ferocity of these creatures. Man-eaters with no regard for human life; savage beasts who only want one thing: to get their teeth on you and rip you to shreds.

Pretty scary, right?

But how dangerous are sharks, really?

On average, there are around 75 shark attacks reported worldwide. Of those 75, the average number of human fatalities works out to around 4 to 5 per year. So, while sharks are by no means cuddly creatures with whom you might want to spend an afternoon swimming around with, the chances of being attacked by a shark are very slim, and chances are even far more unlikely that you will be killed.

To put this in a bit of perspective, let's consider only people who go to the beach. Even among this higher-risk group (after all, you're extremely unlikely to be attacked by a shark while walking in downtown Los Angeles, Sharknado notwithstanding), the chances of being attacked by a shark in the United States is 1 in 11.5 million. The chances of dying from a shark attack is far, far lower: only 1 in 264.1 million.

So, if not sharks, what should we be afraid of?

Cows.

Yes, that's right: cows. In the United States alone, cows are responsible, on average, for 20 human deaths per year. But for some reason, it's sharks who get the bad rap. Thanks a lot, Spielberg.

Let's look at this from a different perspective. Sharks account for 4 to 5 human deaths per year worldwide. Let's err on the side of shark-hate and say 5. To us, it's not a huge number, but for the families of those 5 people, it's a much bigger deal. However, let's look at a different number. That number is 100 million. What is the significance of the number 100 million you ask?

100 million is the approximate number of sharks killed by human beings every year.

Add to that the fact that the worldwide shark population is rapidly declining while the human population in 2012 was 7.046 billion and on a steady upward trend, and you can see which of our species is winning this fight.

Due to huge amounts of shark fishing and destruction of shark habitat by human activities, we are actively and rapidly killing sharks en masse. And we show no signs of slowing down any time soon.

Shark Fin Soup, a pricey and prized delicacy for which many fishermen will catch sharks, cut off their fin, and throw them back to the sea.

So please, by all means, watch Shark Week, and enjoy! But take the time to understand that the sharks might not be the true menace the Discovery Channel makes them out to be. Sharks should be far more frightened of us than we are of them.

And, for the love of God, watch out for cows.

Boo!
Er, moo.

Coming this summer... just when you thought it was safe to go into the pasture... 


Photos:

"Carcharodon carcharias" by Sharkdiver.com - Own work. Licensed under Public domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Carcharodon_carcharias.jpg

"JAWS Movie poster" by PosterRevolution. Licensed under Fair use of copyrighted material in the context of Jaws (film) via Wikipedia - http://en.wikipedia.org/wiki/File:JAWS_Movie_poster.jpg

"Sharksfin" by Arthur Hungry - From Arthur Hungry. All original material on Arthur Hungry is licensed under a Creative Commons License.. Licensed under Creative Commons Attribution-Share Alike 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Sharksfin.jpg

"Anneau anti tetee P1190486" by David.Monniaux - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Anneau_anti_tetee_P1190486.jpg

Who Was Robin Williams?

Robin Williams was born on July 21, 1951. An entertainer in the public eye from the 1970s on, Williams was always there during my life. He was a part of the cultural landscape, someone who played an important role during my formative years. I still remember watching Hook with a sense of wonder and awe. His performance in that film was terrific. I bought him completely both as a middle-aged businessman who had lost his sense of wonder and as the young-at-heart Peter Pan who vowed never to grow up.

As I myself grew up, I saw Robin Williams in more films and television. I saw (and yes, enjoyed) Mrs. Doubtfire, Aladdin, and Jumanji. Nickelodeon, a youth-oriented television network, featured "Nick at Nite" in the evenings, when I would watch reruns of the amazing Mork and Mindy. As I grew older still, I discovered the films Good Morning Vietnam, Dead Poets Society, and Good Will Hunting. Not only was Robin Williams influencing my youth, he would have an effect on the man I was to become. His performances were always engaging, often hilarious, and sometimes heart-wrenching and poignant.

Matt Damon and Robin Williams in Good Will Hunting, one of my favorite films.

With the ability to play a multitude of characters, Williams was an incredibly versatile actor. As one friend said on Facebook, perhaps the question isn't "who was Robin Williams?", but rather "who wasn't Robin Williams?"

A few hours ago, I learned of his recent passing. Like everyone, I was very sad to hear the news. The world has lost a great performer and from all accounts a wonderful person. He has touched a great many lives, and every one of them is grieving the loss of Mr. Williams.

While it's not clear what exactly happened to end the life of Robin Williams, it has been reported that he was suffering from depression recently. If any one good thing can come out of this tragedy, I hope that it is an increased awareness of mental health issues that affect those around us. People who suffer from depression or other mental health problems often do so in silence due to the stigma these conditions have in our society. If you break your leg, you are not ashamed of it; you seek medical attention for the injury. Mental health problems are just as real as physical maladies. No one should be shamed for having problems with mental health or depression. And no one should ever have to suffer in silence.

Now, because this is FactRoulette, I would be remiss if I didn't include an interesting fact that I had not known previously. In this case, from the life and career of Robin Williams: Did you know that Williams was in the original music video for Bobby McFerrin's "Don't Worry, Be Happy"? From 1988, here's the music video:

May you rest in peace, good sir.

Can One Earthworm Become Two?

I'm sure everyone, at some point in their life, has heard that if you cut an earthworm in half, both halves have to potential to survive as independent entities. Sounds pretty cool! But is it true?

Earthworms are pretty remarkable creatures. They have an amazing ability to regenerate much of their bodies. Let's say you were to cut an earthworm in half. The front portion of the worm should include the mouth and a part called the "clitellum," which is the slightly broader un-segmented part, seen clearly in the photo below. Additionally, your cut should include at least ten segments more after the clitellum.

In this case, if you have made your cut in the proper location, the front half of the worm will indeed regenerate and become a whole worm once again. However, the back end of the worm is not viable, and will die. The mouth and the clitellum, which is where the worm's reproductive organs are, are vital to the worm's functions. Without them, there is no chance for survival.

However, while they are not "earthworms," there are some species of flatworm, known as "planarians," that are indeed capable of becoming two separate individuals after being bisected. In this case, the flatworm is split down the middle. Two two halves in some species of flatworm are able to regenerate and become two separate, living flatworms.

Polycelis felina, a freshwater planarian

Sources:

Moment, Gairdner B. (1942). "Simultaneous anterior and posterior regeneration and other growth phenomena in Maldanid polychaetes". Journal of Experimental Zoology 117: 1. doi:10.1002/jez.1401170102

"Gardening with children – Worms". BBC. Archived from the original on 2014-04-28.

Reddien, Peter W.; Alvarado, Alejandro Sanchez (2004). "Fundamentals of planarian regeneration". Annual Review of Cell and Developmental Biology 20: 725–57.


Photos:

"Earthworm". Licensed under GNU Free Documentation License 1.2 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Earthworm.jpg

"Regenwurm1" by Michael Linnenbach - first upload in de wikipedia on 09:58, 16. Feb 2005 by Michael Linnenbach. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Regenwurm1.jpg

"Polycelis felina" by Eduard Solà - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Polycelis_felina.jpg

Humans Only Use 10% of Their Brain. Poppycock!

On July 25th, a fascinating-looking film was released: Lucy, from director Luc Besson.

See the tagline, right near the top? "The average person uses 10% of their brain capacity. Imagine what she could do with 100%."

I'm here to tell you that that statement is complete bunk!

"But," you tell me, "it's a fictional movie! You can't expect every detail to be factually accurate!"

To you, I say, "quiet, stop getting in the way of me making a point."

But perhaps more importantly, this is a common misconception that has been very pervasive and persuasive. So while I don't expect fictional movies to get everything right, I do get annoyed when they perpetuate a myth that we seem to be unable to eradicate!

Human beings do, in fact, use 100% of their brains. In a typical day, a human being will at various times access virtually every part of their brain. Think about it this way: the brain is only about 3% of a human being's total body weight, but it uses about 20% of the body's energy. The brain is very demanding, needing a great deal of energy and resources to operate. If 90% of it were simply unused, excess grey matter, that would be a ridiculous tax on the body's resources for little to no benefit. Evolutionarily speaking, it would make no sense whatsoever.

Here are but a few more reasons why the "10% myth" makes no sense:

• Brain damage: if 90% of the brain is unused, damage to those areas should have no effect. However, damage to nearly every part of the brain will have a detrimental effect.
• Brain scans show activity in all parts of the brain. There is no part of the brain that is never active.
• If the typical human didn't use 90% of their brain, we would see that, through natural selection, people with smaller brains would have had a much higher survival advantage. As previously mentioned, the brain is a very demanding organ. Natural selection would have eliminated the huge, inefficient brains long ago.

PET scan of a human brain. We need all of it, not just 10%!

So, where did this myth come from? Most likely, it seems that misrepresentation or misinterpretation of the results of experiments done in the late 19th and early 20th centuries are the culprit. In any case, use of a miracle drug or exercises to "unlock" the remaining 90% of your brain power will not work.

This is not to say that Lucy is a bad film! Again, it's fiction: treat it as such. I haven't yet seen the movie myself, but I'm looking forward to it. Morgan Freeman and Scarlett Johansson? What's not to like?



Sources:

"Do People Only Use 10 Percent Of Their Brains?". Scientific American. 7 February 2008.

Beyerstein, Barry L. (1999). "Whence Cometh the Myth that We Only Use 10% of our Brains?". In Sergio Della Sala. Mind Myths: Exploring Popular Assumptions About the Mind and Brain. Wiley. pp. 3–24.


Photos:

"Lucy (2014 film) poster" by http://www.impawards.com/intl/france/2014/lucy.html.

"PET-image" by Jens Maus (http://jens-maus.de/) - Own work. Licensed under Public domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:PET-image.jpg

Ravens: Protectors of the Realm?

The Tower of London, on the north shore of the Thames.

The Tower of London holds a prominent place in the history of Great Britain. Founded in 1066, the historic castle has served many purposes over the years: as a prison, an armoury, a treasury, a menagerie, the home of the Royal Mint, a public records office, and the home of the Crown Jewels of the United Kingdom. However, it is some particularly surprising inhabitants of the Tower of London that are the subjects of today's FactRoulette.

If you watch The Game of Thrones or have read A Song of Ice and Fire, you know that ravens play a large role in the fictional land of Westeros. However, did you know that ravens supposedly play a role in the protection of the real-world British monarchy?

A flock of ravens are among the permanent residents of the Tower of London. It is not known precisely when captive ravens were placed in the tower, but they have played a role there through the reigns of many kings and queens, appearing in legends and stories over the centuries. In fact, one superstition holds that "if the Tower of London ravens are lost or fly away, the crown will fall and Britain with it."

London during "the Blitz."

That superstition was very nearly put to the test when most of the flock of ravens died due to stress during the "Blitz," the bombing of London during World War II. In fact, all but one of the Tower ravens died during due to the bombing. Winston Churchill, the prime minister during this period, ordered more ravens to be delivered to the tower in order to return the flock to the proper size.

The ravens continue to be a tourist attraction at the Tower of London to this day, drawing crowds when they are out and about around the tower.

Sources: 

"The guardians of the Tower". The Tower of London.

Jeffrey Vallance (November 2007). "Myths of the Raven. The myths and meanings of the Tower of London ravens". forteantimes.com.

Kennedy, Maev (15 November 2004). "Tower's raven mythology may be a Victorian flight of fantasy". The Guardian (London).



Images:

"Tower of London viewed from the River Thames" by Bob Collowân - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Tower_of_London_viewed_from_the_River_Thames.jpg

"St Paul after the Blitz" by H.Mason - http://www.dailymail.co.uk/news/article-1342305/The-Blitzs-iconic-image-On-70th-anniversary-The-Mail-tells-story-picture-St-Pauls.html. Licensed under Public domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:St_Paul_after_the_Blitz.jpg

"London tower ravens" by ingo zwank (iz) - Own work (own picture). Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:London_tower_ravens.jpg