Baby Pictures

A baby picture of the universe!

http://www.nasa.gov/mission_pages/planck/multimedia/pia16873.html

This is a map of the cosmic microwave background (CMB), the leftover radiation of the Big Bang, made by the Planck mission of the European Space Agency.    This light was emitted when the universe was 380,000 years old. 

There's a number of AWESOME results here.

1. The colors represent small fluctuations in the temperature of the radiation, about 1 part in 100,000 or 0.001%.  Since the average temperature is a mere 2.73 K (2.73 degrees above absolute zero), the fluctuations are roughly 0.00003 K.  To put this in perspective, imagine setting your oven to 350ºF and it never varies by more than 0.008ºF.

2. This light was created just 80,000 years after the universe was cool enough for neutral hydrogen atoms to form.

I couldn't find any baby pictures,
but here I am when I'm about
10% of my current age.

3. It provides the best estimate for the age of the universe.  13.82 billion years.

4. The universe is 4.9% normal matter (protons, neutrons, and electrons for the most part.) Dark matter makes up 26.8% and dark energy 68.3%.

5. The universe is amazingly uniform, isotropic in the physicist's lingo. But there is a tiny difference in the size of the fluctuations in one half of the sky as compared to the other half.  Intriguing!

6. This picture represents the universe when it was just 0.00002750 of its present age.  Let's compare this to one of my students who say is 20 years old; this student was only 5 hours at 0.00002750 of 20 years.    

Warning! Microwave in Use

Billion with B! Santa Monica Sued for $1.7 Billion.

CREDIT: POM 

Before I get to the plaintiff's claim, let's think what $1.7 billion is.  It's $1,700 million.  $1,700,000,000.   Consider spending $1000 a day.  It would take 4,657 and 1/2 years to spend it all.  Santa Monica's total expenditures for fiscal year 2010-2011 was $521.7 million, one-third of what the plaintiff is asking. 

On to the claim.  The plaintiff, Denise Barton, alleges that the city's new parking meters are "causing ringing in her ears, ear infections and tightness on the back, left side of her neck."

Hmmm. Maybe Bob Dylan was right in his Subterranean Homesick Blues, "…watch your parking meters."

What could a parking meter do to cause these ailments?  She asserts it's the wireless signals from these new advanced parking meters the city has installed.

It's the old power lines cause cancer that was updated to cell phones cause cancer a few years ago.  Now it's parking meters.  On September 11, 2011, I dealt with the physics of electromagnetic radiation (light) and how it cannot cause chemical changes.  Microwaves cannot cause atoms and molecules to ionize.

Furthermore, these parking meters are about 1000 times less powerful than your cell phone.  Your cell phone must communicate with a cell tower that can be miles away.  These parking meters send signals to a sensor 5 to 8 feet away according to a city official.

So I'll repeat what I wrote last November:

The World Health Organization (WHO) reports that "[a] large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use."

The National Cancer Institute at the National Institutes of Health says "there is no evidence from studies of cells, animals, or humans that radiofrequency energy can cause cancer."
 

Thanks to Josh Hibbard for tipping me off to the Santa Monica Daily Press article.

Everything We Hear, Everything We See

“Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth.”  Marcus Aurelius.

Marcus Aurelius was Roman Emperor from 161 to 180 C.E. and is one of the greatest of Stoic philosophers.  Although Stoicism does have a natural philosophy, that is, a physics, this article is not about Stoic science, nor is it a comment on the news media.

I saw this quote and realized how it - unintentionally - emphasizes how little of the universe humans actually experience directly.  We have contact with the universe through our senses.  Historically, the senses consist of sight, hearing, smell, taste, and touch, although we possess many more senses such as balance, temperature, and pain.

The human eye responds to certain frequencies of light. Those frequencies or colors we can see are represented by the rainbow.  How we see other colors like brown, pink, and teal is a cool problem in physics and neurobiology/psychology.  There are other 'colors' though.  Radio waves, microwaves, infrared, ultraviolet, X rays, and gamma rays complete the rainbow (electromagnetic spectrum).

You can visualize (pun intended) an electromagnetic wave as an oscillating electric and magnetic field.  If you've played with a balloon with a static charge, you've played with an electric field.  Same for playing with a magnet.  See Maxwell's Silver Magnet for more on electric and magnetic fields.

Sound on the other hand occurs whenever a substance, usually air, vibrates.  In most science texts, the range of human hearing is given as 20 Hz to 20,000 Hz.  Note that the unit Hz is an abbreviation for Hertz and means the number of vibrations per second.  If you place your hand on a audio speaker you can actually feel these sounds.

However only young 'uns can hear up to 20,000 Hz.  Once people reach the age of 20, their hearing starts to degrade.  I have heard anecdotes that children can be easily annoyed when they hear high frequency sounds that their parents can't hear.  You can purchase ringtones for your phone that only young people can hear.

Are their sounds lower than 20 Hz or higher than 20,000 Hz?  Infrasonic tones are those that are lower than 20 Hz.  Earthquakes are a sound wave (remember sound is a vibration) that have frequencies in the infrasonic region.  The stories of birds and livestock being aware of earthquakes before people are sometimes explained as these creatures being able to detect these low frequencies.  There are studies to suggest that infrasonic sounds can cause people to have feelings of nervousness, fear, and anxiety.

Sounds at the other extreme are called ultrasonic.  Ultrasonic cleansers are a popular and safe way to clean jewelry and golf clubs.  How high can ultrasonic tones go?  There's no theoretical limit.  

In condensed matter physics, the study of nearly everything that's not a gas or plasma, there is a phenomenon called a phonon.  A phonon is a particle of sound the same way a photon is a particle of light.  It's quite common for phonon frequencies to be in the THz region.  That's TeraHertz; 10^15 Hz = 1,000,000,000,000,000 Hz.

What piece of these spectrums to we experience?  A  tiny, tiny, tiny,…, tiny piece.  From the Abstruse Goose comes the graph below.  [WARNING! Notice the axes of the graph.  Each tick mark is a power of 10.  That is, each mark is 10 times bigger than the previous one and 10 times smaller than the next.  I tried to graph this on a regular (linear graph for you math and science folks), but i quickly realized that you wouldn't see anything.]

I feel small.

But on the other hand, everything we know about biology, chemistry, physics, geology, astronomy, and the other fields comes from scientists using their puny senses and rational thought to find ways to not only measure, but to comprehend aspects of nature from the Higgs boson, to my favorite molecule ethanol, to huge molecules like DNA, to cellular structures, to tectonic motion, to extrasolar planets, to galactic motion, and all the way to the Big Bang.

I feel huge.

Is Your Cell Phone Killing You?

It could, if you're texting while driving.

My least favorite TV physician, Dr. Oz, says on his website that "experts have grown concerned about the health implications of heavy exposure—specifically, the radiation that the devices emit." Dr. Oz often offers misleading advice, but this is just plain wrong. Experts know that there is no danger from cell phones.

 The World Health Organization (WHO) reports that "[a} large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use."

 The National Cancer Institute at the National Institutes of Health says "there is no evidence from studies of cells, animals, or humans that radiofrequency energy can cause cancer."

 What is it about cell phones? Cell phones use microwaves - a form of electromagnetic radiation. The history of this issue goes back at least to an article in the New Yorker in 1989. Paul Brodeur alarmed the country when some epidemiological studies supposedly showed an increase in cancer in homes near power lines. [More about epidemiology later.] The power lines as all electrical currents generate magnetic fields - extremely low frequency radiowaves. Scientists never found any causal link. In fact, when more careful epidemiological studies were conducted, the correlation between exposure to electromagnetic fields and cancer disappeared.

Now for the science lesson. Cancer is an example of a biochemical reaction gone horribly wrong. While not well understood in many types of cancer, whatever happens causes the uncontrolled growth of abnormal cells. Documented cancer-causing agents are perchloroethylene (used in dry cleaning), tobacco smoke, ultraviolet light, viruses, and environmental toxins like aflatoxin in peanut butter.

How can light (electromagnetic radiation) cause these biochemical changes? Each particle of light called a photon has an energy that depends on the color of the light. As one can see from the diagram, light comes in more colors than just red. orange, yellow, green, blue, indigo, and violet. The photon can be absorbed by an atom or molecule. The energy then is used to excite an electron. If the energy is large enough, the electron can be stripped from the atom.

Now I like to tell my physics students that chemistry is the science of electrons. When chemical bonds are rearranged or broken in a chemical reaction, it's the electrons that are being exchanged between the atoms. So when the photon is absorbed, this can cause a chemical reaction - if the energy is large enough.

What colors of light have enough energy and can cause biochemical effects? Roughly speaking, you need ultraviolet light. This is why I wear sunscreen when I golf. What about microwaves? A microwave photon has about 1/100,000 the energy of a UV photon. No chemical reactions here.

You may be wondering about your microwave oven. That certainly cause some chemical reactions, right? Yes, but not through the mechanism described above. In this case, the microwave photon is absorbed by a water molecule, and this makes the water molecule rotate. This added motion translate as added energy to the water making the water hotter.

So can a cell phone cook your brain? No. Through evolution, mammals have a wonderful mechanism for ridding the body of excess heat - the circulatory system. However, we can calculate how much cooking is going on. A typical cell phone emits about 1 Watt of power. In a five minute phone call, this could cause an increase in temperature of 0.1ºC in the brain tissues near your ear.

Yak away. 


A Note Regarding Epidemiology: This is an important field in science-based medicine. Epidemiology aims to find relationships between exposure to agents and mortality (death) and morbidity (disease). The link between cigarette smoking and lung cancer was first found by epidemiologists, long before any understanding of the physical causes.

A good study is difficult. The most serious threat to a good study is bias. Bias comes in three forms: 1. Selection bias in which subjects are taking part because of an unknown factor that happens to be associated with the exposure and the effect. 2. Information bias where the information gathered is flawed. A typical source of information bias example is when subjects are asked to remember information. 3. Confounders are variables that correlate with both the exposure and the effect. For example , a confounder in the power line study may have been the neighborhoods where the subjects lived.