Keeping faith in science

In an eloquently written piece, NY Times science columnist Dennis Overbye explores the origins of scientific law. Overbye asks, "Are [scientific laws] merely fancy bookkeeping, a way of organizing facts about the world? Do they govern nature or just describe it? And does it matter that we don’t know and that most scientists don’t seem to know or care where they come from?"

Overbye's comments follow a New York Times Op-Ed by Paul Davies, a cosmologist at Arizona State University. Davies recently provoked an avalanche of blog commentary when he asserted in his Op-Ed that science, like religion, rests on faith. Science rests not on faith in God, but faith in the idea of an orderly universe, and without this presumption a scientist could not function.

When I taught physics, I used to begin by making an analogy that I learned from the writings of Nobel physicist Richard Feynman. The analogy assumes that rules exist.

Feynman said that to understand what a physicist does, imagine an observer, watching a chess match. Imagine that this observer knows nothing about the rules of chess. At first the observer will have very basic questions about how the different chess pieces can move. After a while, the observer will start to build an understanding of the rules. Along the way, old rules will be amended, and new rules will be discovered.

Over time, the observer will learn the rules of chess in the same way that physicists learn the laws of nature. As more is understood about the basic rules of game, questions will arise about larger strategies. Just as in science, the questions get bigger and more interesting as you go along. link

Talking stereotypes

In my household, the woman talks more than the man, and this agrees with traditional stereotypes for male and female behavior. The stereotype, however, turns out to be false. In a study conducted at the University of Texas at Austin , about 200 female and 200 male students wore voice recorders during their waking hours that automatically turned on every 12.5 minutes to record for 30 seconds. The recordings were transcribed, counted, and extrapolated to estimate a daily word count. The verdict: men and women averaged roughly the same verbosity, both emitting about16,000 words a day. link

Women's backs are built for pregancy (but still ache anyway)

A scientific comparison between of the lower backs of women and men has shown that women's backs are specially built for carrying the extra weight of pregnancy. Similar studies on our evolutionary ancestors bore the same result.

When human ancestors changed from walking on four legs to two, the bones and muscles of their spines had to evolve to accommodate the shift in weight. The lower spine curved, to shift the shoulders back, and keep our center of gravity over our two legs.

The term center of gravity refers to the mathematical average location of an object's weight. When your the center of gravity extends in front of the end of your feet, you fall over. You can experience this for yourself. Stand keeping the back of your feet and hips against a wall, and move your center of gravity forward by bending at the waist. If you do this, you'll know when your center of gravity is beyond the end of your toes.

Because of the extra weight of pregnancy, women's lower backs evolved differently than men's. The curve of a women's lower back spans three vertebrae; in men, it spans just two. The added vertebra helps distribute the pregnancy weight over a wider area. The joints located behind the spinal cord, called zygapophyseal joints, are 14 percent larger in women than in men, suggesting that the joints can bare more weight. These joints are also oriented at a slightly different angle in women, allowing them to better brace the vertebrae against slipping. link

Google thinks like you

PageRank, the computer program that is Google's search formula, works more like our own mind than previously thought.

In a study published in Psychological Science, people were asked to think of a word that begins with a particular letter, and their responses were recorded and ranked by popularity. The Google PageRank result for the letter turned out to be a good predictor of human responses.

When you get the PageRank search results for a search word, what you see is a list of websites associated with that word, ranked by PageRank's website popularity or importance. A web site's importance is determined by how many web pages are linked to the page, and how many web pages are linked to those pages, and so on. Using this method, a seemingly unimportant word can have great notoriety because of it's association with a popular word.

For example, think of the word myrrh. Nobody uses that word much through the year, but it maintains at least moderate importance because of it's link with Christmas, which has a lot of links. link

Clues to water on Mars lie here on Earth

Our everlasting Mars Rovers are still up there sniffing for evidence of Martian water. To better understand what evidence of Martian water looks like, researchers at the Byrd Polar Research Center at Ohio University are studing the McMurdo Dry Valleys in Antarctica.

Antartic and Martian dry valleys both experience sub-zero temperatures and both have iron-rich soil. Year round, salt water flows in the ground below the Antartic dry valleys. The topographical similarity between these two regions may be an indication of water under Martian soil; and if so, the prospect of present or past water on Mars looks pretty likely. link

Hurricane season wasn't as bad as expected

For the second year in a row, meteorologists expected a worse Atlantic hurricane season than the one we experienced, and meteorologists are beginning to be concerned that future predictions will not be taken seriously.

The conditions this year were ripe for intense hurricane activity. Seventeen named storms were predicted, but the season only produced 14. Only two of the 14 storms were were extremely intense: hurricanes Dean in August and Felix in September. These storms caused catastrophic damage in Mexico.

Meteorologists are still puzzling over the reason for the lower-than-predicted hurricane rate. It is likely that windblown dust from Africa blocked sunlight and keep water temperatures down near the surface of the Atlantic Ocean.

"We are in a time until about 2020 that hurricane threats will be more frequent and more intense on our coastlines. So instead of saying, Ha, ha, ha, there's nothing going on, people should be thankful that there's not as much going on," says Joe Bastardi, a meteorologist with the private weather forecasting service AccuWeather. link

Meanwhile, on Venus...

Lately, Earth and Mars seem to get all the press, but the NASA has ignored Venus since the NASA's Magellan mission used radar to map the planet in 1994 . Venus is Earth's neighbor, on the side closer to the Sun. The planet has roughly the same mass, size, and composition as Earth. Evidence shows that Venus was once partially covered by deep oceans of water. Today, Venus is unimaginably hot, with only a little water left on its surface. How could two planets that were once so essentially alike end up so different?

This week, the European Space Agency (ESA) released eight papers in Nature magazine documenting the findings of the Venus Express mission, their unmanned probe launched in 2005. The ESA has been building their understanding of Venusian weather, which to Earthlings is astounding: above the planet's 460-degree-C surface, the Sun’s energy blasts thick sulphuric acid clouds through an atmosphere that is about 95 percent carbon dioxide.

On Earth, a small amount of atmospheric carbon dioxide warms the surface, which is tempered by vast oceans. On Venus, the thin spots of surface water are vaporizing into space under intense heat. With an atmosphere composed mainly of carbon dioxide, no oceans to cool lava that flows to its surface, and a closer proximity to the sun, Venus experiences an extreme greenhouse effect.

Venus' inhospitable conditions ruins our chances of finding any remaining record of past life there, and makes the possibility of landing an astronaut there a pipe dream. link

Beer fridges are widening our carbon footprints

According to a researcher at the University of Alberta, the secondary refrigerators found in many Canadian households are significant contributors to greenhouse gas emissions.

In Canada, one in three households have a second refrigerator, and most of these second refrigerators are used to keep beverages cold. Beer fridges tend to be older and less energy efficient, 65 percent are more than 10 years old. According to a Canadian researcher, secondary refrigerators in Canada consumed at least as much electricity as 100,000 US homes.

Although the study did not include the US, it's fair to assume that US households contributing to greenhouse emissions in a similar way. The According to the National Resources Defense Council, 98 to 99 percent of US homes have at least one refrigerator, and 18 percent of those have two or more refrigerators. link

Emryonic stem cells - without the embryos

Embryonic stem cells are pluripotent-- they have an almost magical ability to grow into any kind of cell and perform any function. There is a good possibility that some day we may use cells like this to heal injuries and deceases. Until recently, the only way to get these cells was to remove them from the cells of a embryo, a process that is fatal to the embryo and controversial to many.

It was reported on November 20 that a method was developed for making pluripotent stem cells from ordinary skin cells, with no need for an embryo. Two different scientific teams developed the method independently, using specialized viruses to deliver four genes to the skin cell's genetic code. Adding four genes is all it takes to make a embryonic-like stem cell from a skin cell.

Anytime genes are added to normal cells, there is a risk that the cells can grow cancerous. But, researchers are confident that they will soon find a way to switch the cell's genes instead of adding to them, removing the cancer risk.

Having a method for making pluripotent stem cells without using embryos will extinguish the controversy that beleaguers stem cell research. "People working on ethics will have to find something new to worry about," says stem cell researcher Jose Cibelli of Michigan State University. link

Why do the trees change color in the fall?

It seems a fairly obvious question for this time of year. My daughter asked me this question last week, and I was embarrassed that I didn't know what to tell her.

According to News@nature.com, color change in leaves is not very well understood. The predominant theory is that leaves change their color in order to recycle the last bit of nutrients from their leaves before they are lost. Thus, trees grown in areas with less soil nutrients will produce more brilliant leaf colors.

As the weather turns colder, the trees switch to winter hibernation mode. The green chlorophyll in the leaves breaks down and disappears, revealing the yellow carotinoids that have been lurking among the chlorophyll all summer. The brilliant red color that people admire comes from a pigment called anthocyanin, which trees produce in autumn. Why trees expend their precious energy producing anthocyanin is still a matter of study and debate. It is believed that anthocyanin acts as a sunscreen, protecting leaves which are more vulnerable to sun damage after the chlorophyll is gone. The protected leaves can stay on the trees longer, allowing leaf nutrients to be absorbed into the other parts of the tree. link

Gravity victorious in rocket competition

NASA held their 2007 X Prize Cup rocket expo this past weekend near Alamogordo, New Mexico. The weekend's big event was the Northrop Grumman Lunar Lander Challenge, offering 1.35-million dollars in prize money to the company that can demonstrate a new space vehicle capable of landing humans on the moon.

Of the nine companies that registered for the event, only Armadillo Aerospace of Mesquite, Texas was ready to go on launch day. Armadillo is headed by John Carmack, the creator of the video game Doom. Their entry, Module 1, failed the test the first two times and exploded on the third. Interestingly, Armadillo was the only entry to show up for the 2006 competition, and its entry crashed that year, too.

Why is it that a team can't meet the challenge? It's not exactly rocket science. link

Some Neanderthals were redheads

The journal Science reports that at least 1 percent of Neanderthals were fair-skinned redheads. This adaption likely helped the Neanderthals of the high latitudes synthesize vitamin D with less sunlight.

Separate teams isolated a version of a gene called mc1r from the fossils of two different Neanderthals, one 43,000-year-old fossil from Spain, and another 50,000-year-old fossil from Italy. The Neanderthal version of the mc1r gene is similar to a gene found in humans that have fair skin and red hair.

The Neanderthal version of mc1r is not found in humans, which confirms that the gene samples were not mistakenly taken from a human. This also strengthens the currently-accepted theory that humans did not evolve from Neanderthals. link