80beats

How Henrietta Lacks’s Cells Became Immortal and Changed Medical Science

Smriti Rao — Mon, 08 Feb 2010 23:24:01 +0000

You may have learned of the line of cells known as the HeLa strain in a biology class, where a teacher explained the “virtually immortal” nature of these rapidly multiplying cells, and how they played a defining role in science. Over the last six decades, the prolific HeLa cells have been used to develop the first polio vaccines, test chemotherapy drugs, and develop techniques for in vitro fertilization. With their amazing capacity to multiply, the cells are an endless bounty to scientists. HeLa has helped build thousands of careers, not to mention more than 60,000 scientific studies, with nearly 10 more being published every day, revealing the secrets of everything from aging and cancer to mosquito mating and the cellular effects of working in sewers [The New York Times].

But for all that research, little was known about the origin of the cells or about the unwitting donor who supplied them–Henrietta Lacks (The “He” in HeLa stands for Henrietta and “La,” for Lacks). Lacks was a 30-year old black tobacco worker who died of cervical cancer nearly 60 years ago. She died in a public ward for “coloreds” at the then-segregated Johns Hopkins hospital in Baltimore.

In a new book, The Immortal Life of Henrietta Lacks, author Rebecca Skloot explores Henrietta Lacks’s impoverished background and raises troubling ethical questions. She notes that Lacks’s cells are still used to this day, but the family never received a penny and was largely unaware of the fate of the cells. Over the course of 10 years, Skloot worked with Lacks’s daughter Deborah to uncover the real story behind the HeLa cells.

Henrietta had no idea when she died that her tissue was being used for research, still less that it had such miraculous properties; indeed, only in 1973 was she publicly confirmed as the source of the wonder-cells [The Independent]. Bu the cells taken from her cancerous cervix were special: Unlike the human cells that researchers had worked with until then, HeLa cells divided easily and multiplied rapidly, meaning that the self-perpetuating cells essentially became immortal. Since then, thousands of scientists have used Lacks’s cells for research and some biotech companies have reportedly made millions of dollars off them, raising important questions about tissue culture.

In the 1980s a doctor who had removed the cancer-ridden spleen of a man named John Moore patented some of the cells to create a cell line then valued at more than $3 billion, without Moore’s knowledge. Moore sued, and on appeal the court ruled that patients had the right to control their tissues, but soon that was struck down by the California Supreme Court, which said that tissue removed from the body had been abandoned as medical waste. The cell line created by the doctor had been “transformed” via his “inventive effort,” and to say otherwise would “destroy the economic incentive to conduct important medical research” [The New York Times].

In Henrietta’s case, however, the ethical dilemma wasn’t just about using tissue without consent; it also brings to mind the shameful history of using African Americans for medical research. During slavery, doctors tested drugs and operated on black people to develop new treatments and surgical techniques. In the 1900s, black corpses were routinely exhumed and shipped to medical schools for research. Black men died unnecessary deaths in Alabama so scientists could study the effects of their untreated disease in the Tuskegee Syphilis Study [The Chicago Tribune].

Skloot’s book has been described as a thriller combined with Erin Brockovich, but ultimately it pays tribute to the incredible life and death of an unknown African-American woman, and throws light on cancer, racism, scientific ethics and crippling poverty [The New York Times]. Henrietta Lacks was not just a collection of cells. She was a walnut-eyed, square-jawed beauty who favored polished red fingernails and toenails. And sadly, she lived a hard, short life [The Chicago Tribune].

Related Content:
DISCOVER: No Longer Human
The Intersection: The Immortal Life of Henrietta Lacks
The Loom: Henrietta Lacks and the Future of Science Books

Image: Random House

Great Galloping Graphene! IBM’s New Transistor Works at Record Speed

Andrew Moseman — Mon, 08 Feb 2010 21:02:27 +0000

100 gigahertz of processing power—not bad for a single sheet of atoms.

In a paper in Science, researchers at IBM say they have created the fastest-ever graphene transistor, with a cut-off frequency (the highest it can go without significant signal degradation) that at 100 GHz is nearly four times higher than their previous attempt. Similar silicon-based transistors have only been able to reach a turtle-like clock rate of about 40 GHz, or 40 billion cycles per second.

Graphene is a sheet of carbon one atom thick, and electrons move through it extremely fast. This is because they behave like relativistic particles with no rest mass. This, and other unusual physical and mechanical properties, means that the “wonder material” could replace silicon as the electronic material of choice and might be used to make faster transistors than any that exist today [Physics World]. But there are down sides for application: Graphene lacks what’s called a “band gap,” which conventional semiconductors need to turn on and off. And it tends to degrade rather easily during production.

The IBM team crafted a layer of polymer only 10 nanometers thick to protect the graphene from harm. And regarding the band gap issue, researcher Yu–Ming Lin suggested that graphene not be used for the discrete digital signals modern semiconductors deal with. Instead, graphene is better suited for making analog transistors, such as signal processors and amplifiers. Today, such circuitry is largely made from GaAs (gallium arsenide), though GaAs offers nowhere near the same electron mobility [PC World].

Then again, the same IBM research group may have very recently discovered how to create a band gap in graphene. So maybe silicon’s days are numbered, after all.

Image: Jannik Meyer

Study: Genetic Variation Programs Some People to Age Faster

Andrew Moseman — Mon, 08 Feb 2010 17:34:58 +0000

There’s your chronological age, the number that creeps depressingly upward with each passing birthday, and then there’s your biological age, associated with the condition of your body. In a study this week in Nature Genetics, a British team discovered a link between a particular genetic variation and people being several years older in their biological age.

Says study leader Nilesh Samani: “What we studied are structures called telomeres which are parts of one’s chromosomes. Individuals are born with telomeres of certain length and in many cells telomeres shorten as the cells divide and age” [Press Association]. Some people, however, are born with shorter telomeres to begin with, which sets them up to age faster, biologically speaking, and could put them at greater risk for age-related diseases.

Samani’s team studied 500,000 genetic variations, and they keyed on one near a gene called TERC. In a study of nearly 3,000 people, around 38% inherited one copy of the gene variant and were biologically three to four years older than those who did not carry the sequence [The Guardian]. An smaller minority, about 7 percent, had two copies of the gene variant, and the researchers say those people were biologically six or seven years older than people without the variant.

Coauthor Tim Spector says, “What our study suggests is that some people are genetically programmed to age at a faster rate” [BBC News]. The reason, they surmise, could be that the sequence hinders TERC. Normally the gene makes an enzyme called telomerase to repair one’s telomeres, but if this genetic variation causes people to make less of the enzyme while in the womb, they could be born with shorter telomeres.

So what now? Even if Spector and Samani are correct, they say that you can’t just boost telomerase to fix the problem because it carries the risking of causing cancer. However, the genetic sequence could be caught sooner rather than later. The work is expected to pave the way for screening programmes to spot people who are likely to age fast and be more susceptible to heart problems and other conditions early in life [The Guardian].

Image: iStockphoto

Beer Is Good for Your Bones? Well, Maybe.

Andrew Moseman — Mon, 08 Feb 2010 15:47:11 +0000

As study after study suggests that wine might have health benefits, beer tends to get the short end of the stick. But food scientist and beer lover Charles Bamforth wasn’t going to take that lying down, saying: “The wine guys have stolen the moral high ground. I resent the stance that people take that wine is better. It’s not” [Discovery News]. To prove it, he studied the silicon content of beers from around the country, and in a study in the Journal of the Science of Food and Agriculture, found that beer could be a good source of the substance in your diet.

Bamforth found that the beer’s silicon content ranged from 6.4 milligrams per liter to 56.5 milligrams per liter, with an average of about 30 milligrams. Since two pints of beer are just about equal to one liter, drinking two beers at happy hour could provide 30 milligrams of silicon. And while there is no official recommendation for daily silicon uptake, the researchers say, in the United States, individuals consume between 20 and 50 mg of silicon each day [LiveScience]. Light lagers and non-alcoholic beers not only lack flavor, they showed the lowest silicon content in Bamforth’s study. The ultra-hoppy India pale ales came in first.

While Bamforth happily reported his findings about silicon content, the study didn’t claim any link between beer drinking and bone health, which silicon supports. And so some scientists pooh-poohed the “beer is good for you” link that came out in the press release and some media reports. “To conclude any bone health benefits from this study would require a great leap,” said Dr. Tim Byers, deputy director of the University of Colorado Cancer Center in Aurora [ABC News]. While previous studies have suggested that beer could be connected to strong bones, or could have other benefits like limiting kidney stones and gallstones, Bamforth stresses moderation given the detrimental health effects of a few brews too many.

And even he isn’t taking the results too seriously. While studies about the health benefits of beer and wine might make you feel little better about ordering the next pint or glass, he says, that shouldn’t be your prime motivation. “I would first consider flavor and whether you like it or not,” Bamforth said. “Choose the beer you enjoy, for goodness sake” [Discovery News].

Related Content:
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80beats: Tiny Tree Shrews Live on Alcohol, But Never Get Drunk
Discoblog: A Scientific Defense of Beer
Discoblog: Why Do I Feel Woozy? I’ve Only Had One Enormous Glass of Wine
DISCOVER: Stone Age Beer, recreating the brews of the past

Image: flickr/ a4pga

Revealed: The Secret of the Sperm’s Wild Dash to the Egg

Smriti Rao — Sun, 07 Feb 2010 13:41:46 +0000

When it comes to a sperm fertilizing an egg, it all comes down to speed and timing. If the sperm starts swimming at top speed too soon, it will die before it reaches the egg. But if it swims too slowly then it won’t get to its destination in time. Now, scientists have discovered a system in the sperm that acts like a gas pedal, causing the sperm to swim faster as it gets closer to the egg. The findings were published in the February issue of Cell.

Researchers already knew that the speed of a sperm depends on its pH, or its internal acidity levels. The less acidic and more alkline it is, the faster it swims. They also knew that a sperm doesn’t sprint at top speed for its entire trip through a woman’s reproductive tract. It travels relatively slowly for the first part of its journey, and then gets lodged in the sticky folds of the fallopian tubes, resting until another, still unknown signal raises their pH again. This initiates their final race to the egg. “It’s a tough job for a sperm — when it’s deposited it has to travel a long distance to the egg sites,” [said Dejian Ren, who was not involved in the new study]. “This process has been known for many decades, but how it actually happens remained a mystery” [The Scientist].

Now the researchers say they’ve found the mechanism that raises a sperm’s pH and kicks it into high gear. In order to increase its pH and become more alkaline, the sperm needs to jettison protons, and the US scientists have found pores on its surface which allow it to do precisely that. Dr Yuriy Kirichok, who led the research, said: “The concentration of protons inside the sperm cell is 1,000 times higher than outside. If you just open a pore, protons will go outside – we identify the molecule that lets them out” [BBC].

The scientists found that as the sperm got closer to an egg, they react to a substance called anandamide, which is present in the female reproductive tract. That is when these pores or Hv1 proton channels, open–releasing protons and making the sperm swim faster. Gaining a better understanding of what prompts sperm to spring into action could open doors toward developing effective male contraception, or, alternatively, ways to give “slow swimmers” a jolt [Time].

And since anandamide is an “endocannabinoid,” this may explain why male marijuana smokers can have fertility problems–the cannabinoids found in marijuana may mimic the effect of the natural substance. Dr Kirichok said: “Marijuana likely activates sperm prematurely, leaving them burnt out in a matter of hours” [BBC].

For more info, check out this video of the researchers from the University of California in San Francisco talking about the proton activation.

Image: iStockphoto

Geneticists Are On the Lookout for the First Gene-Doping Athletes

Andrew Moseman — Fri, 05 Feb 2010 20:46:46 +0000

We’re only a week away from the 2010 Winter Olympics opening in Vancouver, and the return of the games brings with it the return of crazy stories about how far world-class athletes will go to get even the tiniest edge, legal or illegal. In the journal Science this week, researchers led by geneticist Theodore Friedmann take the opportunity to warn about gene doping, the next looming crisis in cheating at high-stakes athletics.

Genetic doping isn’t new to the headlines—the International Olympic Committee banned it in 2003. But its prevalence is growing, especially since improving testing is starting to weed out more standard forms of cheating like steroids and EPO, a hormone that boosts red blood cell production. Three years ago, German track coach Thomas Springstein was busted after unsuccessfully trying to score Repoxygen, an experimental gene therapy drug that boosts red blood cell production, for his runners. At the Olympics in Beijing, an unidentified Chinese doctor offered stem cell injections to a German journalist posing as a swim coach [Wired.com].

Beyond the ethical concerns of cheating, there is the issue of safety when it comes to athletes trying out new, unregulated therapies, Friedmann says. Most likely, current efforts would be “hamfisted” and dangerous, he said. But “we know there are disreputable people in sport with access to technology and a lot of money” [National Geographic]. Even athletes and coaches without dubious intentions could be duped by claims about therapies that sound legitimately scientific, he says. As a result, he and the other scientists call out their colleagues to develop and test therapies responsibly, under the internationally accepted ethics codes for medical research.

Of course, with so much at stake, it’s a bit of wishful thinking to suggest that all developers or athletes are going to play by the rules. So Friedmann and other researchers are racing to keep up by developing new detection methods. The direct evidence of genetic tampering is hard to find. But telltale side effects could give away gene dopers. The authors note that jacking up genes is “likely to produce broad metabolic, genetic, and proteomic changes” [Scientific American]. That could include levels of fatty acid production, or other system-wide changes that can’t be easily hidden.

So far those kinds of detection tests are limited to animals. But if Friedmann and other scientists bring them to bear in humans, there are other concerns besides effectiveness. He notes that, while delving into athletes’ genomes raises important privacy issues, “that’s kind of the cost of being an elite athlete” [National Geographic]. And even if it works and researchers do come up with sophisticated ways to catch gene dopers, athletes and treatment developers will be moving on to the next generation of performance enhancing drugs. The cat and mouse game continues.

Image: iStockphoto

Robonaut 2: Coming Soon to Space Stations and Assembly Lines Near You

Smriti Rao — Fri, 05 Feb 2010 20:08:26 +0000

Automaker General Motors and NASA share a long history; it goes back to GM supplying the lunar rover used during the later Apollo missions in the early 1970s [MSNBC]. In their latest partnership, GM and NASA have created the Robonaut 2–a humanoid robot that can be used both on Earth and in space. The collaboration comes a time when the Obama administration has called for NASA to focus more on commercial spaceflight and on collaboration with private industry [CNET].

Robonaut 2, which looks a bit like a sleeker version of R2-D2, is a step up from the first iteration made 10 years ago by NASA and the Defense Advanced Research Project Agency (DARPA). That robonaut was intended to be used mostly for space purposes. But the new version, R2, would be equally at home on the International Space Station or on a car assembly line in Detroit.

R2 has been built to replicate the appearance of a human from the waist up so that it can fit into and work in the same spaces, doing the same jobs as people do, sometimes right alongside them [MSNBC]. It has a humanoid torso, head, arms, hands, and fingers, and it displays remarkable flexibility. R2 can also lift and move up to twenty pounds with each arm, which NASA says is about four times more than other humanoid robots. Its four-jointed opposible thumbs allow it to use tools, much like a human. But while the upper half resembles a human, the bottom half of the robot is yet to be designed. Scientists expect R2 to either stand on one leg or be fitted with wheels.

For now R2’s design make it perfect for factory floors. In the past, GM had complained that it spent too much money installing protection systems and cages when it put a robot (usually just a set of mechanical arms with tools) on the assembly line. The company said they thrashed about, without any regard to who or what was next to them. With R2, scientists are hopeful they have a machine that is not just more dexterous but can also be an effective worker on the floor. GM executive Alan Taub explains that Robonaut2’s arms are small and light, with excellent sensors to ensure they stop if they come in contact with something unexpected. “It has a very elegant sensing system so it can sense resistance in the arm,” said Taub. “A child’s hand will stop it” [MSNBC].

The partnership between the automaker and the space agency is expected to yield benefits for both. GM sees the project as a way to develop new sensors, controls, and vision technology that can be integrated into future automobiles and factories to make them safer [Slashgear]. NASA officials, meanwhile, are hopeful of employing R2 in space alongside human astronauts. It could serve, they say, as an assistant on spacewalks by going ahead of the crew to set up the work site.

Image: NASA

Did Russia Use the Baltic Sea as a Nuclear Sewer in the ’90s?

Andrew Moseman — Fri, 05 Feb 2010 18:08:14 +0000

There’s more bad news for the Baltic Sea. Reports had already indicated that it was one of the most polluted bodies of water in the world, and now a report from a Swedish TV station alleges that Russia dumped nuclear and other toxic waste into Swedish waters in the Baltic in the early 1990s.

According to a report by the SVT network, Russian boats sailed out at night to dump barrels of radioactive material, from a military base in Latvia, into Swedish waters. And even though the Swedish government at the time reportedly knew this, no action was taken to find the waste [BBC News]. These accusations—particularly that the Swedish government knew about the dumping and did nothing—aren’t sitting well with current Prime Minister Fredrik Reinfeldt. But Carl Bildt, who was the country’s prime minister during the alleged dumping, says he never heard about it.

Russian Admiral Vladimir Yegorov, who commanded the Baltic fleet in the 1990s, balked at the charges and called them baloney. “The naval forces that were pulling out of the Liepaja naval base in Latvia in the early 1990s did not have chemical weapons, radioactive materials and waste,” Yegorov insisted [The Local].

The Baltic just can’t seem to catch a break. Last month we reported on concerns that shipworms were creeping north and threatening thousands of shipwrecks that the sea’s normally brackish water (meaning less salty than normal ocean water) had preserved. And because the Baltic is largely enclosed—emptying only through a small opening in the south, around Denmark—toxicity takes a long time to escape. The sea was already in such peril, in fact, that a summit of heads of state of countries bordering the Baltic Sea was to take place in Helsinki Wednesday to try to solve the problems [AFP].

Image: flickr / txd

Early Dino Had Crazy Colored Feathers; Resembled “Spangled Hamburg Chicken”

Andrew Moseman — Fri, 05 Feb 2010 15:22:27 +0000

Last week, a study found that an early dinosaur had a red mohawk and striped tail, one of the first pieces of solid evidence regarding dinosaur coloration. But a new study forthcoming in Science goes one step further, mapping in full 3D the strange plumage of the earliest-known feathered dinosaur, Anchiornis huxleyi.

Richard O. Prum, leader of the new study, was among the first to document that pigment-giving structures called melanosomes could survive fossilized for millions of years. The shape and arrangement of melanosomes help produce the color of feathers, so the scientists were able to get clues about the color of fossil feathers from their melanosomes alone [The New York Times]. British and Chinese scientists used this technique to release last week’s color study of the 125-million-year-old Sinosauropteryx, and Prum’s team applied it to the 150-million-year-old Anchiornis.

Because the feathers of Anchiornis (which lived in what is now China) covered nearly its entire body and were so well preserved, Prum’s team could create this detailed color map. They believe its body was grey; it had a reddish-brown Mohawk-like crest, speckles on its face and white feathers with black tips on its wings and legs. The scientists say the pattern of colour on the wings and leg feathers is very like that of modern Spangled Hamburg chickens [BBC News].

The researchers behind last week’s announcement argued that perhaps Sinosauropteryx’s fancy color scheme played a role in courtship displays. The same idea could be true for Anchiornis, and could help explain how feathers evolved in the first place, says paleontologist Philip J. Currie: “Ancient creatures didn’t just sprout feathers and start flying. The feathers were there for another reason first…. Dinosaurs were very visual animals, just like birds are” [Wired.com].

Expect the dino color studies to keep coming, and perhaps the verbal barbs as well. Study co-author Jakob Vinther wasn’t too kind to the team the published last week’s study: “They are in the Stone Age when it comes to understanding melanosome fossilization and interpretation of original colors,” he says [Not Exactly Rocket Science]. His disdain comes because he says the other team’s assessment relied on only one of the two kinds of melanosomes, while color, he says, can vary greatly depending on how the two are mixed.

Image: National Geographic

MRI Brain Scans Show Signs of Consciousness in Some “Vegetative” Patients

Smriti Rao — Thu, 04 Feb 2010 23:28:31 +0000

A few months ago, Belgian man Rom Houben hit the headlines for a misdiagnosis that lasted 23 years. Houben was thought to have lost all brain function in a horrific car accident, and was believed to be in a persistent vegetative state. New evaluations helped determine that Houben actually had normal brain activity, and was yearning to communicate–although the “facilitated communication” his family used to allow Houben to tell his story quickly kicked up a kerfuffle over the validity of the whole tale.

Now, a new study published in The New England Journal of Medicine gives credence to the notion that some patients who have been classified as vegetative are actually conscious, and a rare few may be able to communicate.

The researchers used functional magnetic resonance imaging (fMRI) to scan patients’ brains, and to record any activity generated in the patients’ brains following verbal prompts and questions from the doctors. They found signs of awareness in four patients, one of whom was able to answer basic yes or no questions by activating different parts of his brain. Experts said Wednesday that the finding could alter the way some severe head injuries were diagnosed — and could raise troubling ethical questions about whether to consult severely disabled patients on their care [The New York Times].

Between November 2005 and January 2009, researchers in Britain and Belgium used FMRI to study 23 patients who were considered to be in a “vegetative state.” In 2006, the scientists ran a series of tests to check if the brains of the 23 patients would show any response to certain questions. One of the patients started to show some promise. When doctors asked her to think of playing tennis, areas of her motor cortex leapt to life. When asked to think of being in her house, spatial areas in the brain became active [The New York Times]. Further testing revealed three other “vegetative” patients who showed similar responses.

Then researchers took it one step farther. To open a channel of communication, they instructed one of them, the 29-year-old man, to associate thoughts about tennis with “yes” and thoughts about being in his house with “no” [The New York Times]. They asked the man simple biographical questions like “Is your father’s name Thomas?” Then they checked his brain scans against the answers, and found that he was indicating the correct response each time. To ensure that the patient was making conscious choices, they switched the rules and asked the patient to associate tennis with “no” and his house with “yes.” The patient’s brain scans kept on coinciding with the correct answer.

The results show how much we still have to learn about consciousness. The work “changes everything”, says Nicholas Schiff, a neurologist at Weill Cornell Medical College in New York, who is carrying out similar work on patients with consciousness disorders. “Knowing that someone could persist in a state like this and not show evidence of the fact that they can answer yes/no questions should be extremely disturbing to our clinical practice” [New Scientist].

If more vegetative patients are found to be capable of willfully modulating their brain activity, doctors could potentially communicate with them by asking simple questions requiring a “yes” or “no” response. As fascinating as this development is, problems may arise if doctors ask bigger questions that have ethical implications. “If you ask a patient whether he or she wants to live or die, and the answer is die, would you be convinced that that answer was sufficient?” said Dr. Joseph J. Fins, chief of the medical ethics division at Weill Cornell Medical College in New York. “We don’t know that. We know they’re responding, but they may not understand the question. Their answer might be ‘Yes, but’ — and we haven’t given them the opportunity to say the ‘but’ [The New York Times].

Image: iStockphoto

Quantum Leaf? Algae Use Physics Trick to Boost Photosynthesis Efficiency

Andrew Moseman — Thu, 04 Feb 2010 22:25:11 +0000

The primary reactions in photosynthesis—the first steps in plants’ conversion of sunlight energy into energy stored in carbohydrates—are incredibly efficient. And in a new study in Nature, chemists reveal that they may have found part of the reason why: quantum mechanics.

A couple years ago, scientists first showed in bacteria proteins that the electrons were moving according to a quantum mechanical phenomenon called coherence, rather than abiding by the classical laws of physics. But where those early experiments had been cooled to 77 kelvins (–196 degrees Celsius)—this experiment was the first conducted at room temperature, 294 K, to replicate such effects [Scientific American]. Thus, the new study, which was done on marine algae, suggests this phenomenon can occur in a living biological system.

Quantum coherence occurs when an electron interacts with more than one molecule at a time, entering a multi-state kind of existence. Study leader Greg Scholes explains this quantum trick in a slightly simpler way: “The analogy I like is if you have three ways of driving home through rush hour traffic. On any given day, you take only one. You don’t know if the other routes would be quicker or slower. But in quantum mechanics, you can take all three of these routes simultaneously. You don’t specify where you are until you arrive, so you always choose the quickest route” [Wired.com].

To see if this was happening in their test algae, the scientists targeted lasers onto antenna proteins, which play the role of routing the solar energy the plant receives to places where the photosynthetic reactions are taking place. The incredibly short laser bursts sent electrons spinning that the team could track. Sure enough, the energy passed simultaneously through multiple pathways, the team says, showing coherence at work.

The researchers can’t yet say how widespread this trick is in the plant kingdom. But if coherence happens in many different plants, it could help to explain why photosynthesis is so efficient. “That vibrating electron could put some feelers out and see which path to take,” Scholes says [Science News].

Image: NASA

In a First, Ground-Based Telescope Measures Alien Planet’s Atmosphere

Andrew Moseman — Thu, 04 Feb 2010 17:31:38 +0000

As the count of known planets in distant star systems continues to grow (the number now exceeds 400), so too does the number of ways we have to learn about them. Reporting in Nature this week, a team of astronomers say they have measured the makeup of an exoplanet’s atmosphere using an Earth-based telescope for the first time.

Mark Swain’s team directed NASA’s Infrared Telescope Facility toward HD 189733 b, a planet 63 light years away, discovered back in 2005. HD 189733 b was already known from space-borne observations to harbor several specific molecules in its atmosphere: water, methane, carbon dioxide and carbon monoxide [Scientific American]. Swain’s analysis confirmed those previous findings using spectrography, in which the light from an object is broken down into its component wavelengths, allowing the identification of atoms or molecules by their unique emission or absorption properties [Scientific American]. Swain’s team also turned up something else—a spike in emissions at a very particular wavelength of light, 3.3 microns, that the earlier observations didn’t detect and that Swain’s team can’t explain–at least not yet.

While these and other researchers will likely hurry to investigate the mystery spike, the really important part of Swain’s study is that it shows it is indeed possible to analyze extremely distant planets from telescopes right here on Earth. To do it, they looked for what’s called a secondary eclipse. At its heart, the approach takes the light received on Earth when HD 189733b is behind its parent star and subtracts it from the light received when it is between its star and the Earth. What results is the light due solely to the planet [BBC News]. However, our own atmosphere obscures this information, so Swain team had to study at the exoplanet in infrared and correct for the errors our own planet introduces.

Despite showing signs of the molecules we associate with life, HD 189733 b isn’t a good candidate for life as we know it. It’s among the group called “hot Jupiters”: gas giants orbiting scaldingly close to their stars. However, refining Swain’s method could give astronomers another tool beyond space telescopes like the Kepler mission to search for a world that not only possesses the ingredients for life but also resides at an appropriate orbital distance. This approach vastly increases the number of instruments – far larger than the 3m telescope used in the Nature work – that could be trained on exoplanet atmospheres [BBC News].

Image: ESA, NASA, G. Tinetti (University College London, UK & ESA) and M. Kornmesser (ESA/Hubble)

Dew-Spangled Spider Webs Could Inspire High-Tech Water Collection

Andrew Moseman — Thu, 04 Feb 2010 15:17:27 +0000

You’ve probably heard about the extraordinary strength of many kinds of spider silk, but researchers in China say they’ve figured out another fascinating property of the silk—how it catches water in the air—and created their own copycat material.

For a study in Nature, Chinese scientists looked at the small, non-poisonous cribellate spider’s silk. The secret, revealed by scanning electron microscope, lies in the silk’s tail-shaped protein fibres which change structure in response to water. Once in contact with humidity, tiny sections of the thread scrunge up into knots, whose randomly arranged nano-fibres provide a roughly, knobbly texture [AFP]. In between these knots are smooth areas where the fibers are neatly aligned, allowing water to slide along until it hits a knot, where dewdrops accumulate.

Armed with this knowledge, Jiang’s team then replicated the spider fibres using polymethyl methacrylate, a synthetic polymer that was chosen because it bonds well with water molecules [Physics World]. The researchers report that their creation succeeded in gathering water the same way that spider silk does.

Still, they don’t know for sure why spiders developed this elaborate water-catching system. Jiang says that the purpose could be to gather drinking water so they don’t have to go looking for it, or to “refresh” the web to make it stronger and more robust. There’s also the possibility that the weight of too much water could destroy a web, but the spider’s water system allows droplets to coalesce and then fall off, relieving the web of that weight.

Whatever the reason, Jiang’s team says materials designed to mimic this capacity of spider silk could have benefits like speeding up chemical or industrial processes, or in a simpler sense, helping people in dry areas catch more water. Fog collection entails stretching out nets or canvas on poles and using the mesh to catch moisture from the breeze. The runoff is collected in a pipe or a trough on the ground. The technique, pioneered in the coastal Andes, is being encouraged in poor, dry parts of the world, such as Nepal [AFP].

Image: Wikimedia Commons / Fir0002

Scientist Smackdown: Did a Nuclear Blast on Earth Create the Moon?

Smriti Rao — Thu, 04 Feb 2010 14:38:15 +0000

How on Earth did the moon come into being? If you subscribe to the latest theory, the moon was born out of a nuclear explosion on Earth that sent a chunk of mass flying from the planet’s core into orbit, where it finally became the moon. But cool as that sounds, some killjoy scientists are pooh-poohing the hypothesis, calling it “unnecessary,” “nonsensical,” and “not physically sensible.”

The standard theory of the moon’s origin holds that a giant space object, possibly an asteroid, banged into Earth and sent a large piece of the planet flying into space. That piece eventually became the moon. But the composition of the moon doesn’t seem to support this theory. Researchers say if an asteroid or some such object smashed away part of the Earth, the Moon ought to be composed of about 80 percent of that object’s constituent material and about 20 percent of the Earth’s. But the makeup of moon rock closely mirrors that of the Earth [Popular Science].

An alternate theory, known as the fission theory, suggests that the moon spun out of the rapidly spinning blob of molten rock that would later become Earth [Popular Science]. But no one has been able to explain what caused a huge chunk of earth to spin away and become the moon. Now, researchers Rob de Meijer and Wim van Westrenem have proposed in an online paper that centrifugal forces may have concentrated heavy, radioactive elements like uranium and thorium at the boundary between the Earth’s mantle and its core. Then, they propose, a massive nuclear explosion occurred at the edge of Earth’s core, flinging red-hot, liquid rock into space. The orbiting detritus gradually congealed into what is now our planet’s lone satellite [Discovery News].

Such “georeactors” have existed on Earth before, albeit on a smaller scale than these researchers propose. But de Meijer and van Westrenem have gotten little support for their hypothesis, and plenty of scorn.

Geophysicist Marvin Herndon, who has previously espoused the controversial idea that uranium once sunk to the earth’s core and formed a georeactor there, isn’t buying into the new theory. He says he’s skeptical of a georeactor’s existence at the earth’s core-mantle boundary, explaining that uranium is so heavy that when it liquefies in a nuclear reaction, it should fall to the Earth’s core [New Scientist].

Other scientists asked how the researchers had modeled this kind of explosion, as Princeton University astrophysicist Richard Gott pointed out: “How do they really know it would produce a thin jet of matter?” [New Scientist]. Gott adds that if indeed the georeactor hypothesis was right, then Venus, which is similar in mass and composition to Earth, should have formed its own moon in a similar process–but it didn’t. For further evidence, points out to Pluto, asking “how do you explain Charon, the big icy moon of Pluto? That would require an ‘ice-reactor’, which is a nonsensical idea!”[New Scientist]. David Stevenson, a planetary physicist at Caltech, blew the whole theory right back into space, saying: “The whole idea is not physically sensible,” he says. “Life is too short to spend on things like this” [New Scientist].

The researchers, however, aren’t backing down. They say the best way to test this idea is to look for isotopic signatures on the Moon left over from when the “georeactor” exploded. If they’re there, it’s a good chance that Earth once went critical in a huge way, and our ghostly galleon was tossed into the heavens by the world’s first nuclear detonation [Discovery News].

Dawn of a New Era? NASA Gives $50M to Private Space Companies

Andrew Moseman — Wed, 03 Feb 2010 21:22:11 +0000

A few days after the White House released its budget that proposes axing NASA’s Constellation program and providing more support to private space flight, the Obama administration began to follow through on the second part of that equation. NASA has announced that it’s giving $50 million to five companies to support new space vehicles.

That $50 million isn’t from the revised budget, but rather the American Reinvestment and Recovery Act (or in more common parlance, the $787 billion federal stimulus package). Nevertheless, NASA chief Charles Bolden said these five companies–Sierra Nevada Corporation, Blue Origin, Boeing, Paragon Space Development Corp., and United Launch Alliance–would play a large part in future plans. “Ladies and gentlemen, these are the faces of the new frontier. The vanguard,” said Bolden. “We will certainly be adding to this group in the near future” [Space.com].

Sierra Nevada received the largest grant: $20 million for the development of their “Dream Chaser,” a seven-person crew vehicle based on the Hl-20 runway landing, heavy lifting body concept (looks similar to the canceled Crew Return Vehicle for the ISS) [Universe Today]. Boeing received $18 million to advance its work on a personnel capsule that could be launced by various different rockets; the company has partnered with Bigelow Aerospace on the project. Blue Origin, the pet project of Amazon.com founder Jeff Bezos that DISCOVER has covered before, was awarded nearly $4 million to develop the escape system for its module. The others received funds for environmental controls on board their spaceships or for monitoring the health of old rockets that could be reused.

Those totals are small compared to the $3.5 billion NASA has already provided SpaceX and Orbital Sciences Corporation to develop vehicles to reach the International Space Station, as well as the monetary support that could reach private space companies if Congress approves Obama’s budget with its change of direction for NASA. But Bolden acknowledged that this announcement was tied to the Administration’s new plans, and NASA will be working more and more with these companies in the days to come.

Image: flickr / PauloReCanuto