Cassini misses, Dextre's ready

In July 2005, a group of NASA scientists got very interested in Enceladus, a small moon of Saturn. At that time, the Cassini spacecraft flew over the surface of Enceladus' south pole, and discovered a dozen or so warm geysers spraying water vapor and ice crystals. That was surprising because moons as small as Enceladus, which is just 300 miles wide, do not usually generate enough internal heat to create such activity. The existence of the plumes hinted that there might be a liquid water ocean beneath the surface, and the possibility of liquid water always brings the possibility for life.

Last Wednesday, the Cassini spacecraft flew into the mysterious icy plumes erupting from Enceladus. The flyby, however, turned out to be a bust. Passing only 125 miles from the base of the plume, an "unexplained software hiccup" prevented the spacecraft's Cosmic Dust Analyzer from transmitting data to the onboard computer. Flybys planned for later in 2008 may be able to repeat the plume fly-through to try to collect the observations missed this time around. link

Much closer to Earth, in the International Space Station, astronauts have just completed assembling Dextre, a special purpose dexterous manipulator (SPDM). Dextre is a robot with two large arms that will allow it to transport objects, use tools, and install and remove equipment on the outside of space station. Sensors allow Dextre to "feel" objects and automatically react to movements or changes. Astronauts will operate Dextre from inside the space station, looking through Dextre's four mounted cameras. The robot is designed to function with spacewalking astronauts, or to work independently on tasks that previously would have required a spacewalk. link

Struggling against greenhouse gases

There is strong support to the idea that the use of plug-in electric cars, cars that recharge overnight, would greatly aid the reduction of greenhouse gas emissions. Research from the University of Texas, to be published in the June issue of Environmental Science & Technology, suggests that electric cars would would aid drought. Accorcing to the report, filling the road with 10-million plug-in electric cars by 2015 would require an additional 1.1 percent or so of water used by electric power plants. Nonetheless, I don't think that kills the whole electric car idea. link

But here's some real bad news. Using data provided by the Chinese government, researchers at the University of California have calculated China's greenhouse gas emissions by 2010. The results are that within two years, Chinese emissions of greenhouse gases will have vastly outstripped the reductions achieved by all the countries that have signed up to the Kyoto protocol combined.

Chinese greenhouse gas emissions are estimated to be between 600- and 1,200-million metric tons greater than they were in 2000. Even the minimum figure is five times as large as the 115.90 million metric ton in reductions which the US Energy Information Agency estimates will have been achieved by signatories of the Kyoto protocol by 2010.

"The emissions growth rate is surpassing our worst expectations, and that means the goal of stabilizing atmospheric CO2 is going to be much, much harder to achieve," says Maximillian Auffhammer of the University of California, Berkeley. link

Jupiter Probe confirms ideas about Earth's Van Allen Belts

The first thing you have to know is that the Earth is submerged in the center of doughnut-shaped belts made of energetic charged particles. We call this the Van Allen Belts, after James Van Allen who discovered the Earth's radiation belts 50 years ago using the first US satellite, Explorer I.

Within the Van Allen belts, we observe occasional flurries of high-energy electrons that are known to mess with the electronics inside communication and other types of satellites. It has been theorized that these high-energy electrons are accelerated by very low-frequency radiowaves. Understanding these high-energy electrons is key in being able to predict their behavior, and make the Van Allen belts safer for satellites.

Using data collected at Jupiter by the Galileo spacecraft, Dr Richard Horne of British Antarctic Survey (BAS) and colleagues from UCLA, and the University of Iowa found that a special type of very low frequency radio wave is strong enough to accelerate electrons up to very high energies inside Jupiter's magnetic field.

According to Dr Horne, "We've shown before that very low frequency radio waves can accelerate electrons in the Earth's magnetic field, but we have now shown that exactly the same theory works on Jupiter, where the magnetic field is 20,000 times stronger than the Earth's and the composition of the atmosphere is very different. This is the ultimate test of our theory." link

Japan and Korea go to space

Space Shuttle Endeavour left Cape Canaveral today to deliver part of a Japanese space laboratory and a Canadian-built robotic arm system to the International Space Station (ISS). With the arrival of Japan's lab, all 15 partner countries in the ISS are represented in orbit.

The $100-billion space station is 60% complete after a decade of construction and must be finished by the time the space shuttle program is retired in 2010. Endeavour is carrying the first part of an elaborate Japanese space laboratory, which the Japanese have been working on for over 20 years. About the size of a double-decker bus, it will be the station's largest laboratory and will have facilities for art and "orbital dance", along with experiment racks for biomedical studies, fluid physics research and life science. link

It was announced yesterday that the first South Korean astronaut will be a woman. Yi So-yeon, 29, is a biotechnology engineer who is finishing her doctorate. Yi will serve as a payload specialist with two Russian cosmonauts for a seven- or eight-day mission to the International Space Station. The man intended to be the first South Korean in space has been grounded for violating security protocol. link

Depressing news about SSRIs

The antidepressant Prozac and related drugs are no better than placebo in treating all but the most severely depressed patients, according to a recent reassessment of clinical data.

Prozac is a SSRI, or selective serotonin reuptake inhibitor. Since its launch, more than 50 million people with depression have been treated with Prozac. Other SSRIs include fluoxetine (Prozac), venlafaxine, nefazodone, and paroxetine (Seroxat or Paxil).

A previous study had indicated that the benefits of antidepressants might be exaggerated. So, UK and US researchers led by Irving Kirsch of Hull University, UK, studied clinical trials of these drugs, using all data presented to the US Food and Drug Administration (FDA). The researchers have concluded that SSRIs do not work for most patients, stating "compared with placebo, the new-generation antidepressants do not produce clinically significant improvements in depression in patients who initially have moderate or even very severe depression". link

Bad Biofuels

United Nations Environment Program spokesman Nicholas Nuttall states: “There was an unfortunate effort to dress up biofuels as the silver bullet of climate change. We fully believe that if biofuels are to be part of the solution rather than part of the problem, there urgently needs to be better sustainability criterion.” In other words, we're not seeing the whole biofuels picture. And the picture isn't good.

Two papers published in Science explain that if the full emissions costs of producing biofuels are taken into account, growing and using biofuels will result in more greenhouse emissions than conventional fuels. The factor that has previously been ignored in the biofuel life cycle is the carbon emissions that will result from clearing new land for growing fuels. Using existing food-producing farmland for growing fuel does not solve the problem, because switching from food to fuel will reduce the supply of food crops, and that will motivate farmers elsewhere to clear more land. Tropical rainforest land is already being cleared for this purpose, but the studies show that the carbon cost is great even if less-lush scrubland is cleared for farming. link

Prior to the release of these studies, scientists have been wary of biofuels. In his book, The Omnivore's Dilema, Michael Pollen explains that by some estimates, growing and producing one gallon of corn ethanol takes 9/10-ths of a gallon of gasoline. This is because petroleum is used in production and application of fertilizers, as well as irrigation, distillation, and transportation of the biofuel. The October 2007 issue of National Geographic dedicates a cover story to the environmental price of biofuels. link

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