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Archive for May, 2011

Think I’ll Bang My Head Against the Wall Now…

May 31, 2011 1 comment

File:Cell phone.jpgSo the news media is going nutso over the World Health Organization‘s decision to list cell phones as “possibly carcinogenic to humans.”

Let me be absolutely clear on this: No new studies have been released to spur this decision. The decision was reached by a team of 31 scientists who reviewed the existing scientific literature.

After reviewing the evidence they decided that even though there was no conclusive evidence that cell phones cause cancer, they are going to list it as a possible danger to humans.

They are playing it safe; erring on the side of caution; not counting their chickens before they’re hatched, whatever you want to call it.

[Update (11:57 AM): Here is an excellent explanation on the evidence the WHO used to make its decision, and what their decision actually means.]

This is a touchy subject. While I generally agree with playing it safe, in this case I disagree with the WHO’s decision.

Basically they are saying they need more long-term studies. However, since it is impossible to prove a negative, we will never be able to prove that cell phones don’t cause cancer. You would need an infinite number of studies to do that!

It’s just like on Glee when Kurt made the point that 

You can’t prove there isn’t a magic teapot floating around the dark side of the moon with a dwarf inside of it that reads romance novels and shoots lightning out of its boobs.

Same deal with cell phones. There is no plausible mechanism by which cell phones can cause cancer since the radiation is non-ionizing. There is also no dramatic increase in cancer rates coinciding with the dramatic increase in cell phone use in recent years.

Critics get around this point by saying that it takes decades for effects to really take hold. On average, yes that is true, but after 10-20 years of regular cell phone use by a large percentage of the population we should still expect to see some signs of adverse health effects.

So I disagree with the WHO. This little announcement is going to cause undo panic and fear.

But the “be afraid of microwaves” crowd has gotten much louder in the last few years, and I suspect this announcement by the WHO is largely due to public pressure rather than scientific evidence.

But who am I, right? I’m just a humble science blogger with a degree is physics who has looked at the scientific evidence and seen that there is no cause for alarm.

So I’m gonna go ahead and say “Don’t panic!”. But I have a sneaking suspicion people are going to anyway…

Its Official! Go Jets!

May 31, 2011 Leave a comment

Its official. True North Sports and Entertainment is about to have a press conference to announce their purchase of the Atlanta Thrashers.

They have already told the Winnipeg Free Press that the deal has been finalized.

The sale still has to be voted on by the Board of Governors in a few weeks, but that vote is expected to go smoothly.

Also, the name of the team won’t be announced today. That seems to indicate to me that the team will not be called the ‘Jets’, but will take on the name of Winnipeg’s current AHL affiliate team, the Manitoba Moose.

But that is speculation. What is for sure though, is that Canada now has 7 NHL teams.

Awe. Some.

5 Things I’ve Learned From One Year of Blogging

May 30, 2011 3 comments

Happy Anniversary! A Quantum of Knowledge went online one year ago today!

It seems like the older you get, the shorter the years get. Because it certainly doesn’t seem like a year since I started blogging.

But it has been. 312 posts. 63,000 hits. Not to shabby :)

From what I’ve read, the majority of blogs die out in the first few months after creation. So how do you keep it going?

There are a few tidbits I’ve picked up over the past year that have not only kept me blogging, but kept me loving blogging.

1. Write about what YOU find interesting.

Too often I find myself trolling the news trying to find stories that I think others might be interested in. But this inevitably causes problems.

First, if I don’t find the subject interesting, I’m not going to do a good job writing about it.

Second, you never know what people will find interesting. If you try to pick topics based on what you think people will like, you are just playing a guessing game.

Stick with what you know. Because if you write about things you like and you find fascinating, you will write great posts that people will want to read and share with their friends.

2. Post OFTEN!

It doesn’t have to be a long post. If you are busy, treat your blog like a Twitter feed. Or just post a video you thought was funny. Just post SOMETHING!

Regular posts not only keep your readers coming back, but they keep you in the habit. Just like an exercise routine, you need to keep it up regularly in order to make it a habit.

After you keep a regular schedule for a few weeks, it will be a cinch to continue posting all the time!

3. Talk about yourself

Even if you write your blog anonymously, you should still talk about yourself.

What are your personal feelings on an issue? Have you been happy or sad lately? Did you just go on vacation? If so, where to?

In my case, even though I blog about science, I’ve found that some of my most popular posts were actually about me and not science news.

Whether it be where I spent my weekend, or my Top 10 Sci-Fi Movies, people seem to like hearing about my life. And I’m happy to oblige them.

Not only that, but I’ve found that personal anecdotes do wonders when trying to explain a complicated subject. Inserting a funny personal story into a technical post makes it much more readable.

4. Don’t be afraid to take a break now and then

If you haven’t blogged in a while, it can feel like a weight on your shoulders. You start to think,

“I haven’t posted in a while. I really should…but Dancing with the Stars is on…”

And the more days you miss, you more you feel like you should blog. But when you start feeling like you should, you really don’t want to.

So my advice? It’s ok to miss a few days of blogging. It’s even ok to miss a week or two. In fact, you should probably put the blog aside on purpose every now and then so you don’t get burned out!

And if you’ve intentionally taken a break from blogging, you will soon find that you miss it. You will want to blog again.

5. Do it because you love it

“Physics is like sex: sure, it may give some practical results, but that’s not why we do it.”
— Richard P. Feynman

The same goes for blogging. In my case, spreading the word about good science or disparaging pseudoscience may be in the best interest of the public; but that’s not why I do it.

I do it because I love writing. I love writing about other things that I love. Science, video games and other geekery, it’s all good.

And if you enjoy the fact that you are blogging, it will show through in your posts. People will be drawn to come back and keep reading your stuff.

So that’s it. That’s what I’ve learned. I hope you all have enjoyed the blog so far, and I hope you continue to enjoy it!

Awful(ly Awesome) Re-enactment of Aeris’ Death Scene From FFVII

May 29, 2011 Leave a comment

Are you an uber-nerd like me? Then you’ll find this quite amusing.

The actual death scene is still perhaps the single most memorable moment from a video game I’ve ever seen.

Shock wave from a Trombone Caught on Film

May 29, 2011 Leave a comment

The weak shock wave emanating from a trombone was captured on film and presented at the 161st Meeting of the Acoustical Society for America in Seattle.

The researchers used schlieren photography to capture the images. This method is able to image fluids through the changes in their refractive index and is used largely in aeronautical engineering to study air flow around airplanes.

It’s also wicked-cool :)

So Just HOW Do You Measure the Shape of the Electron?

May 26, 2011 3 comments

ResearchBlogging.org

A paper recently published in Nature is generating quite a bit of media buzz. [PhysOrg, BBC, Fox, PhysicsWorld]

The paper is entitled ‘Improved measurement of the shape of the electron’ and describes, well, a new method for measuring the electron’s shape.

I love when physics paper titles are easy to understand :)

Anywho, the main thrust of the paper is that the electron appears to be spherical to a very high degree of accuracy. In fact, the press release from the Imperial College of London states that,

the electron differs from being perfectly round by less than 0.000000000000000000000000001 cm. This means that if the electron was magnified to the size of the solar system, it would still appear spherical to within the width of a human hair.

Wow! Now that is pretty darn spherical.

But now you’re thinking “Hey wait, I thought the electron was a wave? Or a string of energy? Or a cloud of virtual particles? How can it actually be spherical?”

These are excellent questions. Indeed, when we first learn about atomic structure in science class the electron, protons and neutrons are all depicted as perfect spheres. As we learn more, we know that this is only an approximation, an easier way of visualizing the complicated subatomic structure.

The truth is, the electron isn’t (well, probably not) spherical. We don’t really know for sure. Current theories point to the most accurate picture being that the electron is a cloud of particles, blinking in and out of existence, which contribute to its mass and size.

So what this paper and these news outlets are actually saying is that this experiment has shown that the electron behaves as though it is a sphere.

Even more accurately, the electric dipole moment of the electron is approximately zero, which is what we would expect from a perfect sphere with uniform charge distribution.

Ok, I know I just said a mouthful. So let’s go through exactly what I mean about the electric dipole moment, and then we’ll go through what this paper actually measured.

Let’s begin with what an electric dipole moment actually is. Imagine you had two particles, one with a negative charge (-q), and one with a positive charge (+q). If you put these two charges close together, you will create special electric field pattern. This type of arrangement creates what is called an electric dipole moment (EDM). The EDM vector (p) is defined as the of the charge on the two particles (q) times the displacement vector between them (d).

The electric dipole moment vector (blue arrow) points, by definition, from the negative charge to the positive charge.

However, you can also create an EDM if you were to have a particle with an uneven charge distribution.

For example, imagine you had a sphere with a total charge +q. In this case, the charge is evenly distributed and you don’t get an EDM.

A perfect sphere with a uniform charge distribution does not have an electric dipole moment.

But now imagine you had an oddly shaped particle that was “squished” at one end.

In this case, there is more charge at one end of the particle than there is at the other. This uneven charge distribution gives the particle its own EDM.

A not-so-perfect sphere has a non-uniform charge distribution. The higher concentration of positive charge at one end creates an electric dipole moment (red arrow).

So if the electron is not perfectly spherical, it should have an EDM. If it has an EDM, we should be able to measure it to infer the electrons shape. Simple, right?

Now, the Standard Model of Physics predicts that the EDM of the electron is too small for us to currently measure; our equipment is just not sensitive enough. But there are variations on the theory that say the electron’s EDM may actually be larger enough to measure using our current technology.

So finding the electron’s EDM will help narrow down our current theories on the subatomic universe.

The existence of an EDM may also help explain why there is so much matter in the Universe and so little antimatter. If the reason for this apparent imbalance in matter and antimatter is the result of an as-of-yet-undiscovered particle interaction, then the current theories of particle physics predict that there should be a measurable EDM for the electron.

So this explains why this experiment is so important. Now lets explain the experiment.

In a simplified picture, the electron EDM in an applied electric field will either point in the same direction as the field, or in the opposite direction. The energy of an EDM in an electric field depends on the direction of the EDM in relation to the electric field.

This means that the EDMs that align with the electric field will have a different energy than those that align against the field. This difference in energy is proportional to the magnitude of the EDM.

So how does one measure this energy difference? One way is to align the spins perpendicular to the field, which will cause them to precess and you can then measure the precession rate, which is proportional to the energy difference.

This effect can also be described in terms of how the two energy states interfere with one another. This interference between the two states can be measured using an interferometer. If there is an EDM present, then a phase shift should be seen in the interferometer signal. If the applied electric field is reversed, then the phase shift should change sign.

So the authors of the paper went looking for this phase shift. They used molecules of Yttrium Fluoride and fired them at a speed of 590 m/s into an apparatus which has a constant electric and magnetic field.

A radiofrequency pulse is applied which excites the molecules into their respective energy states. They are then allowed to interact for a certain amount of time (a few milliseconds) and it is during this time that the molecules in the different energy states develop a phase difference.

A second radiofrequency pulse is applied and the number of molecules which end up in the lower energy state is measured and is proportional to the phase difference they developed during their interaction time in the electric field.

This phase difference is measured via the applied magnetic field and creates an interference curve.

An example of an interference curve from measuring the phase difference via the magnetic field. (Figure 3 from this paper)

If the electric field is reversed, then a small phase shift in the interference curve is seen. Remember that the phase shift is proportional to the electron EDM.

So by varying certain parameters like the magnetic field and the frequency of the radiofrequency pulses, the authors were able to extract the numerical of the electron EDM from the data.

Over 25 million pulses of YbF were used to collect this data. Not only that, but many experiments had to be done to determine systematic sources of error in the experimental setup.

Things like fluctuations in the applied magnetic field, electric field plate potentials not being completely symmetric, magnetic fields generated in the magnetic shielding during switching of the electric field are all sources of error which had to be considered.

So after all this work they finally arrived at their calculated value of the EDM for the electron. The value turned out to be de = (-2.4 ± 5.7stat ± 1.5syst) × 10-28 e · cm, where the first error term is from statistical uncertainty and the second is from systematic uncertainty.

Notice that the error on this measurement makes it consistent with zero and consistent with previous work.

However, this measurement is 54 times more precise than the previous one the author’s previous measurement and puts an upper limit on the EDM of the electron which must be less than 10.5 × 10-28 e · cm.

The next step in these types of experiments is to reduce the uncertainty of the measurements. The authors believe that they should be able to do this using cold molecule techniques and get their measurement down into the 10-29 e · cm range.

Be sure to check out another blog post about this paper by Chad Orzel, author of the blog “Uncertain Principles” and the book “How to Teach Physics to Your Dog”.

Hudson, J., Kara, D., Smallman, I., Sauer, B., Tarbutt, M., & Hinds, E. (2011). Improved measurement of the shape of the electron Nature, 473 (7348), 493-496 DOI: 10.1038/nature10104

No More Tears in Heaven

May 25, 2011 Leave a comment
File:Astronaut-EVA.jpg

Photo: NASA/JPL

Drew Feustel, an astronaut currently in space with the crew of the Space Shuttle Endeavour, had a small problem with his spacewalk on Wednesday.

Some anti-fog solution he had rubbed onto his visor started to flake off during the spacewalk. Since the anti-fog solution is really just dish soap, it caused a problem because it flaked off into his eye.

If you have ever gotten soap in your eye, you know its terrible, terrible sting.

Aside: I used to put dish soap on my glasses when I played hockey so they wouldn’t fog up. I didn’t realize this was a “space-age” solution.

So poor Drew’s eyes started to water. But because of the lack of gravity, the tears would not fall down, they just sort of hung around on his eyeball.

“Tears in space don’t run down your face,” he said, according to lead spacewalk officer Allison Bollinger

“They actually kind of conglomerate around your eyeball,” Bollinger recounted.

Eventually, he was able to rub his eye on a device inside his helmet to release the fluid from the surface of his eye.

So disaster averted. This indeed sounds like one of the ultimate #firstworldproblems