Storing solar heat

The photovoltaic materials needed to turn the sun's rays into electricity are still relatively expensive, given the power they can produce. And, since the sun doesn't always shine, solar energy must be stored if it is to provide a continuous stream of electricity. A recent NYTimes Science article describes a technology that collects solar energy as heat, and stores the heat to enable 24-hour-a-day power generation.

Using mirrors and lenses, the sun's rays are reflected and focused on to a tank of molten salt. The salt reaches temperatures high enough to boil water. It's a lot cheaper to store energy as heat than it is to store it as electricity. The article cleverly points out that a coffee thermos and a laptop computer battery can store roughly the same amount of energy; and the battery cost 30 times more. By cooling the hot salt, steam is made continuously, rain or shine, night and day. The steam powers conventional electric generators. link

A step closer to theraputic cloning-- treating deseases with the patient's own cells

Science Magazine's news site, ScienceNow, reports that scientists have moved a step closer toward being able to use patients' own cells to treat their diseases. This process is referred to as therapeutic cloning. A team led by neuroscientist Lorenz Studer of the Sloan-Kettering Institute in New York City was able to show that mice with a Parkinson-like movement disorder significantly improved after being implanted with brain cells derived from their own tissue.

The new study is the first to show that cells from a diseased animal can be used to treat the very same animal. The researchers gave mice brain lesions to create a Parkinson-like disorder in which knocked out the use of the neurotransmitter dopamine on one side of their brains, limiting their ability to control paw movements.

To treat the Parkinson-like disorder, the researchers isolated a cell produced in a mouse's ovary called an oocyte, and transferred the nucleus of the mouse's skin cell into the ooctye. These modified cells were grown into early embryos, which were clones of the afflicted mice. Many of these cells grew into dopamine-producing neurons that the scientists could implant to treat the brains of the original donors.

The sick mice treated with their own cells showed a significant improvement in their ability to control paw movements. The improvement only occurred in mice treated with their own cells. link

You can't buy happiness for yourself

Social psychologist Elizabeth Dunn of the University of British Columbia (UBC) in Vancouver wanted to find out what kind of spending makes people happier: spending money on yourself, or spending it on others.

Dunn's researchers gave 46 UBC students envelopes containing either a $5 bill or a $20 bill and told them how to spend it. Some were told to spend it on themselves; some were told to spend it on someone else. After interviewing the students later, it turned out that those who spent it on others, as a gift or donation to charity, were happier than those who blew it on themselves.

According to Science Magazine, two more studies yielded similar results. Dunn's team polled 16 employees of a Boston company before and after they received bonuses of various sizes, and they gathered data on income, spending, and happiness from 632 people across the United States. In both groups, happiness correlated with the amount of money people spent on others rather than the absolute amount of the bonus or income.

If you bought yourself a cup of coffee or an ice cream today, and tomorrow bought one for someone else. Which would bring you more long- or short-term happiness? link

Thermoelectric materials: making electric current from heat

We make electricity from heat all the time. Burn fuel, the heat moves the piston, the piston turns the generator, and we can plug in our X-Box or our vacuum cleaner. But imagine if we could heat a wire and make electric current move through the wire just by heating it.

Thermoelectric materials are capable of absorbing heat and turning it into electric current. Today's thermoelectric materials aren't very efficient, but they are used in niche applications like in cooling certain microchips. NASA uses them on spacecraft that are too far from the sun to use solar power.

Recently, researchers at MIT and Boston College have discovered a simple way of making thermoelectric materials, and these theromelectric materials are 40 percent more efficient than normal. The process involves grinding bismuth antimony telluride into fine particles and then pressing it back together. link

If thermoelectric materials can someday be easily made in bulk, these matrials could be used to make engines or air conditioners significantly more energy efficient. A typical car engine loses roughly a third of it's energy to heat. Thermolelectric materials could someday cool the engine of a hybrid car, and take a good portion of the lost energy to power the electric drive motor. Such a vehicle would be super efficient. Another possiblity is using thermoelectric materials absorb heat from the air-- a much more efficient way of cooling a building. link

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