free debate

February 28, 2011

Phantom Limbs and Mind Tricks

Ever wanted to be like Zaphod Beeblebrox*, and have a third arm attached? Well, according to recent research, this may be possible.

Each of us has a mental body image, which corresponds to our actual physical bodies. Thus, we experience having one head, two legs, two arms, etc. It seems likely that this body image is limited by the way our bodies actually are. Thus, an amputee can still "feel" the limb they're missing, but a person cannot "feel" a third arm. Or can they?

Neuroscientists at the Swedish Karolinska Institutet performed an experiment on healthy adult volunteers, in which they placed a realistic rubber right arm on a table next to the subject's real right arm, and covered it with a sheet, so the subject could not tell at a glance which arm was theirs at a glance. Then, as the volunteer watched, both of the right arms were rubbed with a small brush simultaneously. One would expect that a person would only feel one brush, the one touching their real hand. Instead, the brain gets confused, and resolves the issue by accepting both right hands as real. The person perceives having three arms, instead of two. They even reacted when either right hand was threatened with a kitchen knife, regardless of whether or not the hand was real.

It's a promising result for prosthetics and other medical applications, and those who are often at risk. If a limb can be accepted into the body image, as a person's own, then it can be controlled, theoretically, just as easily as a real limb. It's also just an interesting nuance to our understanding of how the mind interprets physical experiences. It's a fascinating demonstration of how little we really understand our own perception, and how flexible our brains can be.

Source: Science Daily-Scientists Create Illusion of Having Three Arms

*Apologies to those who haven't read Douglas Adams' Hitchhiker's Guide to the Universe, or who don't like it.

February 25, 2011

Is Evolution Bad?

When someone tells me they do not believe in evolution, I like to ask why. Answers can range, but recently I heard one that interested me: that evolution is bad. I had heard evolution called many things, but bad? To be clear, the person I was talking to meant bad as in evil. They saw evolution as being the inspiration and justification for various historical atrocities. Although it caught me off guard, it is not an uncommon criticism to hear, and it deserves some time to discuss here.

The skeptical community's first response to arguments like this is often to point out the poor logic of it. Calling evolution bad is actually a great example of the appeal to consequences. The appeal to consequences is when an argument asserts that because of the consequence of an idea, it is therefore true or false. This line of reasoning falls apart once you realize that there are realities of the universe that are not good for society and our species in general. For example, the fact that atomic weapons can be used to kill millions human beings does not mean they therefore do not exist. Knowing whether or not something is good or evil does not tell you if it is a reality.

You can point out logical fallacies in disagreements all day long, but without the proper delivery they often come off as hollow. Before you point out a logical fallacy to someone, first agree that logic is a necessary tool for finding the truth. Don't take for granted that everyone always agrees with logic, as this is simply not true. If you are debating in front of an audience, it can be effective to point out fallacies if you do it right, but often just comes off as snobbish. Being able to recognize logical fallacies is a useful skill but presenting them to someone who disagrees with you is a whole separate issue. If you do want to point out the logic do so by analogy. I would simply say something to this effect:

It could be possible that woman are smarter than men (or visa-versa) and the discovery of that could have major social consequences. Some of those might be positive and others negative but neither would make the original fact more or less true. The consequence of something is not what makes it true.
Find the style and analogies you like, but hopefully the idea is clear.

Back to my main point: so, the social consequences of evolution don't change whether it's true. But does evolution have negative social impacts? This question of evolution and morality is one I am actually very interested in. It is a matter of historical fact that evolution has been used to justify atrocities. Eugenics, the forced sterilization of a group of people that share certain undesirable traits, is the most obvious example of this. The justification is typically that evolution favors the strong and so we can improve or evolve the human race but artificially selecting for those traits. So what scientific merit does this have, if any?

None. Let me walk through the problems with this justification. The first problem is a widespread misunderstanding of the theory of evolution. According to the theory of evolution there is no such thing as 'more evolved' or 'higher evolved'. Humans are no more evolved than a bacteria, although we are more complex. Evolution by natural selection pressures all species to develop traits advantageous to their environment. Different environments require different traits. After all, bacteria can survive in many more environments than we can. This brings me to the second flaw. The idea that evolution is all about the 'survival of the strongest' is another mistake. Flies are not very strong, yet they are pervasive across the planet. The same is true of many other animals. Finally, natural selection favors genetic diversity. Natural selection forces some traits to remain constant in a certain environment. Outside of that, it is generally advantageous to diversify. This way, if the environment changes, it is more likely that some members of the species will be able to survive. So in the end, any attempt to "improve" human beings in terms of evolution is both meaningless and doomed to fail.

So can any morality be derived from evolution good or bad? Like the Earth going around the Sun, evolution is a fact. Facts should be used to inform morality, but I leave it to philosophers to debate where morality is derived from. What I will say is that evolution, when properly understood, tells of a connection with each other and nature which I would call spiritual. The idea that we share a distant ancestor with every living thing on this planet gives a new appreciation for the beauty of the world around us. It in no way dispels our responsibility to help one another. It may be that it instead extends that responsibility beyond our own species. Again, let me be clear that this paragraph is more my own personal thoughts on the issue. This is by no means universally accepted or a direct outcome of evolution. That said, I am not the only person who feels this way.

February 23, 2011

Our Celestial Home to Scale

Space is big. In fact, space is so big that calling it big is an understatement. Trying to get this enormous size across is one of the greatest challenges of teaching astronomy. I have seen a lot of demonstrations and images trying to get across this very concept. Recently while browsing the Internet, I found a image that blew me away. I think this brings together the relative sizes and distances in the solar system in a very clean and easy-to-understand graphic. It is simple, while still including details such as light travel times, past and future spacecraft, and some of the more recently discovered dwarf planets. It is a very long image, so click on the link to see the whole thing. It is well worth your time.

Click here to see the full post

February 21, 2011

Cutting Through Light

We're all familiar with the concept of a laser. They appear through our culture, from laser pointers to light shows, from metal cutting to CD players. The laser, or light amplification by stimulated emission of radiation device, works by exciting atoms. This causes electrons to jump up to an "excited state," and then drop down to normal, emitting a photon in the process. The diagram below shows how this works:

The electrons orbit the nucleus of protons and neutrons at certain, discrete levels. It can be at 1, 2, or 3, for instance, but not at 1.5 or 2.33. There is a specific amount of energy between each layer, and a wavelength of light (a photon) corresponds to that energy level. A laser uses this property to emit a focused light beam, the laser we're all familiar with.

As cool as lasers are, though, there's always a question in physics about "what would the opposite of this be?" In the case of a laser, it would be some sort of focused beam that cancelled out light, instead of amplifying it. It's theoretically possible; the incoming light photons would have to be captured and be absorbed, converting into heat. But, until recently, no one had ever tried to create this anti-laser. Yale physicist Douglas Stone, along with his research time, have now done a proof-of-concept, called the "coherent perfect absorber," or CPA. It uses a silicon wafer to capture and cancel two laser beams, absorbing light at specific frequencies in the exact opposite of a laser.

As with all innovations, there are lots of potential applications for this new technology. But the cool thing, to me, is not those uses. Instead, I admire the question itself. A scientist saw a hole in our knowledge and our technology, did some thought experiments to find potential ways it could work, then built the mechanism to show how it works. This creative innovation is one of the most fascinating and fun parts of doing science.

Sources: Science Daily- World's First Anti-Laser Built
How Stuff Works- "How Lasers Work"

February 18, 2011

Frog Teeth

(c) National Geographic
The natural world is filled with vestigal traits: whale hips, snake legs, wisdom teeth, etc. These are unnecessary features that disappear over time through natural selection. Because the features provide no advantage to survival or reproduction, and in some cases may have been a disadvantage, the traits are reduced over numerous generations, and will eventually vanish completely. By a principle known as Dollo's law, once a trait is lost completely, it cannot come back. It is just gone.

However, a new analysis of the frog species Gastrotheca guentheri suggests that, in some cases, lost traits can return. This species is the only one, of the over 6000 described species of frog, to have teeth on the lower and upper jaws. Most frogs only have tiny teeth on the upper jaw, if at all. In fact, based on genetic data, the frog lineage lost teeth over 200 million years ago. So, where did this species get them?

According to the study lead by John Weins of Stony Brook University, G. guentheri redeveloped complex lower teeth about 10 million years ago. It makes sense, with the animal's diet: the frog is carnivorous, and having teeth helps to catch prey. However, this is the only species to evolve this solution to the problem. Most other carnivorous frogs instead develop bony pegs on the lower jaw, rather than true teeth. The case of G. guentheri seems to be in violation of Dollo's law. One possibility that the paper suggested was that there could be a loophole. Most frogs do still develop upper teeth; this species could have just transposed that development onto the lower jaw as well. They would not have had to completely re-evolve true teeth. Still, though, this unusual adaptation is a bit of a mystery. This species is clearly off of the lineage that lost bottom teeth. There are far more common solutions than redeveloping true teeth. It's certainly an interesting evolutionary quirk, and provides new paths for more research into the mechanisms driving evolution.

Source- National Geographic: Frogs Evolve Teeth - Again
For more details, view the original publication.

February 16, 2011

A Pendulum That Speeds Up With Quantum Bullets

Every once and a while a science article comes around that is so mind-blowing, I tell just about everyone I know. For me, this was one of those news articles. It is fairly intuitive that if you take a pendulum -like a grandfather clock- and submerge it in water, the friction between the pendulum and and the water will slow it down. Now imagine a liquid that causes the opposite effect: a fluid that causes the pendulum to speed up as it passes through. Scientists have actually known for several years now that by using a supercooled fluid this can  be done. Now we know why.

In order to pull off this trick, researchers Timo Virtanen and Erkki Thuneberg of the University of Oulu had to create a special type of fluid know as a Fermi Liquid. In order to explain more, let me quote from the article on Wired Magazine.

Ultracold Quantum ‘Bullets’ Make Pendulums Speed Up

"When chilled down into a Fermi liquid, particles no longer interact strongly with one another as they do at higher temperatures. Instead there appear quasiparticles, which are the combination of a particle itself along with how it affects the environment around it. Like the original particle, each quasiparticle carries spin, charge and momentum."

"The researchers calculated that the quasiparticles ricochet around in the liquid like bullets, increasing the force on the pendulum. They do not, as ordinary particles would, interact with each other strongly enough to create resistance to the pendulum moving through them. “That’s why the behavior is different,” says Thuneberg."

So, at these super cold temperatures, the particles in the fluid literally change how they interact with one another and with outside objects. Instead of interactions with particles slowing down the down the pendulum as it passes through the liquid, the quasiparticles are imparting their energy into the pendulum through collisions. The energy from these collisions is speeding up the pendulum.

I am amazed that it is even possible to do this at all. It is counterintuitive and marvelous results like this that keep me coming back to science for more and more. This research has some practical implications and will likely be used to better understand many systems, but it may not be something that is going to change how we live or will likely ever lead to a something you see at the store. It is the kind of research that is driven by curiosity. These are the breakthroughs that capture the imagination. This beautifully depicts how science, while being rigid and tough, is simultaneously filled with some of most exciting stories there are to tell.

Image is by Loadmaster (David R. Tribble). Used via Creative Commons and Wikimedia Commons (

February 14, 2011

We are Coming Back

Wow. It feels like I have not written a post in forever, and it has been much too long. Ali Marie and I are going to work to update more often again. My goal is to have at least 1-2 posts a week going up over the next month. Hopefully, we will soon get back into a rhythm, and post more frequently.

In the past, when there has been a gap, I have tried to give a brief cover as to what has happened in that time. Instead, here I want to talk about the future. Going forward, I want to write more of what I have done in the past, the news updates and the scientific unknowns, but maybe also talk more about how to communicate science. I have not talked about this much in the past, which is odd since really that is what I do. For the last 5 years, I have volunteered and worked paid positions teaching science. I have done this in lots of different venues from camps to museums to urban schools. The story of science is too important to be left out of any corner of our society.

So with that, look for more posts to come soon.

February 12, 2011

Happy Darwin Day!

There have been a few ideas, through history, that completely revolutionize how we think about the world and jump start a long path of scientific inquiry: Copernicus' heliocentric model of the solar system and Newton's laws of motion and gravitation are two striking examples. These provide a fundamental base for modern astronomy and physics. 152 years ago, a book was published that presented a similar fundamental base for all of biology. This book was titled On the Origin of Species, and it was the first to present the idea of evolution by natural selection.  Every field remotely related to biology - ecology, genetics, paleontology, medicine, and more - provides evidence for and is influenced by this the fact of evolution. Today would be the 202nd birthday of its author, Charles Darwin. So, to honor the man and celebrate his idea, have a slice of Darwin cake and look around you at the incredible diversity of life on this planet.

There's a lot of opposition to evolution in the general public, which is an issue I deal with frequently and will likely discuss in more detail in the future. For now, though, I want to leave you with a sense of how beautiful and incredible our planet is, and how much more so considering every living thing we see came from a simple prokaryote 3.8 billion years ago.

If you're interested in reading Darwin's works, they are available as open source documents at Darwin Online.

Credit to Ben of the UChicago Secular Student Alliance for making the awesome Darwin cake.