Both Sides Cite Science to Address Altered Corn

Both Sides Cite Science to Address Altered Corn

 

In France and the rest of the European Union, farmers would not be allowed to plant a type of corn altered to produce insecticide.

A proposal that Europe’s top environment official made last month, to ban the planting of a genetically modified corn strain, sets up a bitter war within the

European Union, where politicians have done their best to dance around the issue.

The environmental commissioner, Stavros Dimas, said he had based his decision squarely on scientific studies suggesting that long-term uncertainties and risks remain in planting the so-called Bt corn. But when the full European Commission takes up the matter in the next couple of months, commissioners will have to decide what mix of science, politics and trade to apply. And they will face the ambiguous limits of science when it is applied to public policy.

For a decade, the European Union has maintained itself as the last big swath of land that is mostly free of genetically modified organisms, largely by sidestepping tough questions. It kept a moratorium on the planting of crops made from genetically altered seeds while making promises of further scientific studies.

But Europe has been under increasing pressure from the World Trade Organization and the United States, which contend that there is plenty of research to show such products do not harm the environment. Therefore, they insist, normal trade rules must apply.

Science does not provide a definitive answer to the question of safety, experts say, just as science could not determine beyond a doubt how computer clocks would fare at the turn of the millennium.

“Science is being utterly abused by all sides for nonscientific purposes,” said Benedikt Haerlin, head of Save Our Seeds, an environmental group in Berlin and a former member of the European Parliament. “The illusion that science will answer this overburdens it completely.” He added, “It would be helpful if all sides could be frank about their social, political and economic agendas.”

Mr. Dimas, a lawyer and the minister from Greece, looked at the advice provided by the European Union’s scientific advisory body — which found that the corn was “unlikely” to pose a risk — but he decided there were nevertheless too many doubts to permit the modified corn.

“Commissioner Dimas has the utmost faith in science,” said Barbara Helfferich, spokeswoman for the environment department. “But there are times when diverging scientific views are on the table.” She added that Mr. Dimas was acting as a “risk manager.”

Within the European scientific community, there are passionate divisions about how to apply the growing body of research concerning genetically modified crops, and in particular Bt corn. That strain is based on the naturally occurring soil bacterium Bacillus thuringiensis and mimics its production of a toxin to kill pests. The vast majority of research into such crops is conducted by, or financed by, the companies that make seeds for genetically modified organisms.

“Where everything gets polarized is the interpretation of results and how they might translate into different scenarios for the future,” said Angelika Hilbeck, an ecologist at the Swiss Federal Institute of Technology in Zurich, whose skeptical scientific work on Bt corn was cited by Mr. Dimas. “Is the glass half-empty or half-full?” she asked.

Ms. Hilbeck says that company-financed studies do not devote adequate attention to broad ripple effects that modified plants might cause, like changes to bird species or the effect of all farmers planting a single biotechnology crop. She said producers of modified organisms, like Syngenta and Monsanto, have rejected repeated requests to release seeds to researchers like herself to conduct independent studies on their effect on the environment.

In his decision, Mr. Dimas cited a dozen scientific papers in finding potential hazards in the Bt corn to butterflies and other insects.

But the European Federation of Biotechnology, an industry group, contends that the great majority of these papers show that Bt corn does not pose any environmental risk.

Many plant researchers say that Mr. Dimas ignored scientific conclusions, including those of several researchers who advised the European Union that the new corn was safe.

“We are seeing ‘advice-resistant’ politicians pursuing their own agendas,” said one researcher, who like others asked not to be identified because of his advisory role.

But Karen S. Oberhauser, a leading specialist on monarch butterflies at the University of Minnesota, said that debate and further study of Bt corn was appropriate, particularly for Europe.

“We don’t really know for sure if it’s having an effect” on ecosystems in the United States, she said, and it is hard to predict future problems. About 40 percent of corn in the United States is now the Bt variety, and it has been planted for about a decade.

“Whether Bt corn is a problem depends totally on the ecosystem — what plants are near the corn field and what insects feed on them,” Ms. Oberhauser said. “So it’s really, really important to have careful studies.”

Bt crops produce a toxin that kills pests but is also toxic to related insects, notably monarch butterflies and a number of water insects. The butterflies do not feed on corn itself, but they might feed nearby, on plants like milkweed. Because corn pollen is carried in the wind, such plants can become coated with Bt pollen.

Ms. Oberhauser said she had been worried about the effect of Bt corn on monarch butterflies in the United States after her studies showed that populations of the insect dipped from 2002 to 2004. But they have rebounded in the last three years, and she has concluded that, in the American Corn Belt, Bt corn has probably not hurt monarch butterflies.

Still, she said there was disagreement about that as well as broader causes for worry. Monarch butterflies may have been saved in the United States, she said, by a fluke of local farming practices. Year by year, farmers alternate Bt corn with a genetically modified soy seed that requires the use of a weed killer. That weed killer, Monsanto’s Roundup, eliminated milkweed — the monarch’s favored meal — in and around corn fields, so the butterflies went elsewhere and were no longer exposed to Bt.

“It’s a problem for milkweed, but it made the risk for monarchs very small,” she said.

Still, she said, other effects could emerge with time and in farming regions with other practices. For example, Bt toxin slows the maturation of butterfly caterpillars, which leaves them exposed to predators for longer periods.

“Sure, time will give you answers on these questions — and maybe show you mistakes that you should have thought about earlier,” she said.

For ecologists and entomologists, a major concern is that insects could quickly become resistant to the toxin built into the corn if all farmers in a region used that corn, just as microbes affecting humans become resistant to antibiotics that are prescribed often. The pests that are killed by modified corn are only a sporadic problem and could be treated by other means.

Scientists also worry about collateral damage because Bt toxin is in wind-borne pollen. Most pollens “are highly nutritious, as they are designed to attract,” Ms. Hilbeck said, wondering how a toxic pollen would affect bees, for example.

Having reviewed the science, insurance companies have been unwilling to insure Bt planting because the risks to people and the environment are too uncertain, said Duncan Currie, an international lawyer in Christchurch, New Zealand, who studies the subject.

In the United States, where almost all crops are now genetically modified, the debate is largely closed.

“I’m not saying there are no more questions to pursue, but whether it’s good or bad to plant Bt corn — I think we’re beyond that,” said Richard L. Hellmich, a plant scientist with the Agriculture Department who is based at Iowa State University. He noted that hundreds of studies had been done and that Bt corn could help “feed the world.”

But the scientific equation may look different in Europe, with its increasing green consciousness and strong agricultural traditions.

“Science doesn’t say on its own what to do,” said Catherine Geslain-Lanéelle, executive director of the European Food Safety Authority. She noted that while her agency had advised Mr. Dimas that Bt corn was “unlikely” to cause harm, it was still working to improve its assessment of the long-term risk to the environment.

Part of the reason that science is central to the current debate is that European law and World Trade Organization rules make it much easier for a country or a region to exclude genetically modified seeds if new scientific evidence indicates a risk. Lacking that kind of justification, a move to bar the plants would be regarded as an unfair barrier to trade, leaving the European Union open to penalties.

But the science probably will not be clear-cut enough to let the European ministers avoid that risk.

Simon Butler at the University of Reading in Britain is using computer models to predict the long-term effect of altered crops on birds and other species. But should the ministers reject Bt and other genetically modified corn?

“My work is not to judge whether G.M. is right or wrong,” he said. “It’s just to get the data out there.”

Cancer Fight Goes Nuclear, With Heavy Price Tag

Cancer Fight Goes Nuclear, With Heavy Price Tag

 
Pete Freeman prepares for treatment for prostate cancer in a fixed beam room at at Loma Linda Medical Center in Loma Linda, Calif.

There is a new nuclear arms race under way — in hospitals.

Medical centers are rushing to turn nuclear particle accelerators, formerly used only for exotic physics research, into the latest weapons against cancer.

Some experts say the push reflects the best and worst of the nation’s market-based health care system, which tends to pursue the latest, most expensive treatments — without much evidence of improved health — even as soaring costs add to the nation’s economic burden.

The machines accelerate protons to nearly the speed of light and shoot them into tumors. Scientists say proton beams are more precise than the X-rays now typically used for radiation therapy, meaning fewer side effects from stray radiation and, possibly, a higher cure rate.

But a 222-ton accelerator — and a building the size of a football field with walls up to 18-feet thick in which to house it — can cost more than $100 million. That makes a proton center, in the words of one equipment vendor, “the world’s most expensive and complex medical device.”

Until 2000, the United States had only one hospital-based proton therapy center. Now there are five, with more than a dozen others announced. Still more are under consideration.

Some experts say there is a vast need for more proton centers. But others contend that an arms race mentality has taken hold, as medical centers try to be first to take advantage of the prestige — and the profits — a proton site could provide.

“I’m fascinated and horrified by the way it’s developing,” said Anthony L. Zietman, a radiation oncologist at Harvard and Massachusetts General Hospital, which operates a proton center. “This is the dark side of American medicine.”

Once hospitals have made such a huge investment, experts like Dr. Zietman say, doctors will be under pressure to guide patients toward proton therapy when a less costly alternative might suffice.

Similar cost concerns were expressed in the past about other new technology like MRI scanners. While those have become accepted staples of medical practice, there is still concern about their overuse and the impact on medical spending.

Dr. Zietman said that while protons were vital in treating certain rare tumors, they were little better than the latest X-ray technology in dealing with prostate cancer, the common disease that many proton centers are counting on for business.

“You can scarcely tell the difference between them except in price,” he said. Medicare pays about $50,000 to treat prostate cancer with protons, almost twice as much as with X-rays.

Proponents, however, are adamant that proton centers provide better treatment.

“It all comes down to the physics,” said Dr. Jerry D. Slater, the head of radiation medicine at Loma Linda University Medical Center in Southern California. “Every X-ray beam I use puts most of the dose where I don’t want it.” By contrast, he said, proton beams put most of the dose in the tumor.

Loma Linda built the nation’s first hospital-based proton center in 1990 and has treated about 13,000 patients. Its success has inspired others.

Companies have sprung up to help finance, build and operate the proton centers. In some cases, local and state governments, seeking to attract medical tourists, have chipped in. Such financing is allowing proton centers to be built even by community hospitals or groups of physicians.

One of the biggest and most costly projects, with a bill exceeding $140 million, is being undertaken by Hampton University in Virginia, a historically black college that does not have a medical school.

“Here at Hampton we dream no small dreams,” said William R. Harvey, the president. He said a proton center would help African-Americans, who have higher rates of some cancers than whites. And he said a medical school was not needed — that doctors would be hired to run the outpatient facility.

Some of the planned centers will be very close together, raising the odds of overcapacity. Two proton centers are planned for Oklahoma City, for example, and two more in the western suburbs of Chicago.

The institutions building the centers say there is a need for many more of them. The existing centers, which collectively can treat only several thousand patients a year, are turning people away. And patients who are accepted often have to spend weeks in a city far from their homes.

Proponents say that more than 800,000 Americans — representing nearly two-thirds of new cancer cases — undergo radiation therapy each year. If only 250,000 of them could benefit from protons, they would fill more than 100 centers.

“If they built one across the street I wouldn’t worry about it,” said James D. Cox, chief of radiation oncology at the M. D. Anderson Cancer Center in Houston, which opened a $125 million proton center last year.

X-rays, which are high-energy electromagnetic waves, pass through the body, depositing their energy all along the way, not just in the tumor. By contrast, protons — subatomic particles with a positive electrical charge — can be made to stop on the tumor and dump most of their payload there.

Tumors in or near the eye, for instance, can be eradicated by protons without destroying vision or irradiating the brain. Protons are also valuable for treating tumors in brains, necks and spines, and tumors in children, who are especially sensitive to the side effects of radiation.

When 10-year-old Brooke Bemont was about to undergo X-ray treatment for a brain tumor last summer, a doctor warned her mother, “Do not plan on your daughter ever going to Harvard.” The radiation would damage Brooke’s mental capacity, she explained.

So the family, from St. Charles, Ill., spent five weeks in Boston as Brooke was treated with protons at Mass. General. “If there was a potential to save even a little of her brain tissue, there was no question that we would do it,” said Christal Bemont, Brooke’s mother. She added that Brooke was now apparently cancer-free and doing fairly well.

Head, spine and childhood cancers are rare, though. Most people undergoing proton treatment are men with localized prostate cancer.

Proton therapy can help avoid the worst side-effects, like impotence, by exposing the bladder and rectum of a prostate patient to less radiation than X-rays. The stray radiation, though, from the newest form of X-rays, called intensity-modulated radiation therapy, is already low, diminishing any advantages from proton therapy.

“There are no solid clinical data that protons are better,” said Dr. Theodore S. Lawrence, the chairman of radiation oncology at the University of Michigan. “If you are going to spend a lot more money, you want to make sure the patient can detect an improvement, not just a theoretical improvement.”

An economic analysis by researchers at Fox Chase Cancer Center in Philadelphia found that proton treatment would be cost effective for only a small subset of prostate cancer patients.

Lack of data aside, men are flocking to proton treatment.

“I’m 67 years old, and the last thing I want to do is wear a diaper for the rest of my life,” said Pete Freeman of Spokane, Wash., who was undergoing treatment at Loma Linda.

Some men hear about proton therapy from the Brotherhood of the Balloon, a group of 3,000 men who have had the treatment. (A balloon is inserted into the rectum and filled with water to immobilize the prostate during treatment.)

The organization, which now gets some financial support from Loma Linda, was founded by Robert J. Marckini, a former Loma Linda patient who calls himself “Proton Bob.”

At Loma Linda, prostate cancer treatment requires about two months of daily sessions. The actual irradiation, which the patient does not feel, takes only about a minute. Most men with early prostate cancer have no symptoms from their disease and many say the treatment has few immediate side effects, other than fatigue and an urgency to urinate.

“We go have our treatments, and we go out and play golf,” said Harry Phillips, an accountant from Tacoma who was treated recently at Loma Linda.

Doctors are also learning how to use protons to treat lung and breast cancer. And over time, doctors say, costs should come down as the technology improves and it becomes more routine to build and operate proton centers. One company is trying to develop a $20 million proton system and has received orders from several hospitals.

On the horizon is therapy using beams of carbon ions, which are said to be even more powerful in killing tumors. Touro University says it will build a combined proton and carbon therapy center outside San Francisco, to open as early as 2011. The Mayo Clinic is also seriously considering one. Such centers will cost even more — as much as $300 million. 

Musical Focus: New Speakers Don't Bother Bystanders

Musical Focus: New Speakers Don't Bother Bystanders

 
A prototype for a personal sound system could allow one to enjoy audio without uncomfortable earphones or headsets while not bothering neighbors.

Experts have invented a way for audiophiles to listen to music over loudspeakers that don't annoy people standing nearby.

"You may soon be able to enjoy audio without those uncomfortable earphones or headsets and not bother your neighbors," said researcher Chan-Hui Lee at the Korea Advanced Institute of Science and Technology.

The "personal sound system " that Lee and his colleagues envision focuses sound waves from several loudspeakers onto a listening zone. Outside this zone, the sound waves would be much less audible.

The researchers devised a simple prototype involving half-inch speakers, nine of which were arranged in a row 13 inches (33 centimeters) long. They found there was a 20-decibel or more difference in sound intensity between the listening zone and outside it — the difference between, say, a normal conversation and a whisper.

Lee and his colleagues suggest personal sound systems could find use with laptops and televisions. "But the ultimate goal are mobile phones and PDA systems," Lee told LiveScience.

To fit personal sound systems on portable devices such as mobile phones, obviously smaller speakers are needed. Unfortunately, such speakers generally do not broadcast the wide range of audio frequencies personal sound systems need. "The research there is ongoing," Lee said.

If such portable systems are ever devised, people might listen in, say, by holding players in front of them, although the exact design still needs to be worked out, Lee added.

The researchers detailed their findings Nov. 30 at the Acoustical Society of America meeting in New Orleans. 

Questionable Numbers for a Questionable Remedy

Questionable Numbers for a Questionable Remedy

Echinacea might be useful as a cold remedy or preventative, but science hasn't shown it yet

When you first feel the sniffles and wonder what to grab from your medicine cabinet, perhaps you should first check some numbers. Especially if one of your choices is echinacea.

The evidence on whether echinacea helps fight colds has been confusing. A 2005 study concluded that the herb doesn't help, but a few months ago, a team of pharmacists claimed that it decreases the odds of getting a cold by 58 percent and reduces the length of colds by one to four days.

Scientists continue to debate whether echinacea helps fight colds effectively. iStockphoto

The evidence favoring echinacea is not as rosy as the second study might suggest, however. For one thing, the statement that echinacea decreases the odds of getting a cold by 58 percent is based on terminology that can be misleading. Second, that study was a meta-analysis, a compilation of previous studies. It was a less rigorous and less tightly controlled analysis than the first. Although that meta-analysis may suggest that echinacea shouldn't be dismissed entirely as a cold remedy, it certainly doesn't prove that the herbal remedy works.

For practical purposes, people want to know whether they're less likely to suffer from a cold if they take echinacea, and if so, by how much. It's not hard to compute that from data in the study. Patients who didn't take echinacea got a cold about 65 percent of the time, whereas those who did got sick about 45 percent of the time. So people who took echinacea had about a 30 percent smaller chance of getting a cold (^{65 – 45}/₆₅).

So why does the study conclude that echinacea reduced the odds by 58 percent rather than 30 percent? It turns out that in ordinary speech, "reducing your odds" means the same thing as "reducing your chances," but in statistics, their meanings are quite different.

Statisticians define the "odds" as the ratio between the chances that something will happen to the chances that it won't. Although the term has infiltrated our vocabulary, we don't tend to think about odds much in regular life, outside of a gambling context. We keep it simpler and just talk about the chances that something will happen, rather than the ratio between the chances that it will happen and the chances that it won't.

According to the data from the study, the reduction in the odds of getting a cold if you take echinacea turns out to be almost twice as high as the reduction in the chance of getting a cold if you take echinacea. Seeing why requires a bit of arithmetic. If you hadn't been taking echinacea, you would have had about a 65 percent chance of getting a cold and about a 35 percent chance of not getting one. That means that the odds of getting a cold without echinacea would be just under 2:1 (to be precise, the chances would be 65.23 percent, so the odds would be 0.6523/0.3477, or 1.88).

If you were taking echinacea, you would have had about a 45 percent chance of getting the cold and about a 55 percent chance of beating it. So the odds of getting a cold would have been just over 4:5 (to be precise, the chances would have been 44.87 percent, so the odds would have been 0.4487/0.5513, or 0.81). That means taking echinacea would have decreased the odds from 1.88 to 0.81, or by 58 percent (^{1.88 – 0.81}/_1.88).

 

Colds cost the U.S. economy 40 billion dollars a year. iStockphoto

 

Of course, most people would be delighted to have 30 percent fewer colds. But there are reasons to suspect that echinacea may not really be able to accomplish that. Understanding those reasons requires unraveling some details of how the two studies were done.

In the 2005 study, Ronald B. Turner of the University of Virginia School of Medicine and his colleagues did the kind of work one typically imagines in a medical study: They randomly divided the patients into two groups, gave one group echinacea and the other a placebo, exposed all the patients to the cold virus, and monitored them to see how many in each group caught a cold. Neither the doctors nor the patients knew who was receiving echinacea.

The researchers found that the patients who had taken echinacea were a tad better off, but the effect was so small that it might well have been caused by random variations. In technical terms, the effect was not "statistically significant."

The later meta-analysis was an entirely different sort of project. Instead of putting virus-infected cotton swabs in patients' noses, Dr. Craig I. Coleman of the University of Connecticut School of Pharmacy and his colleagues compiled data from previous studies and did some math.

The idea of a meta-analysis is to combine the data from a bunch of small studies into a single large study. The advantage of a big study is that it isn't impacted by random effects as much as a small one, just as a big ship doesn't rock in the waves as much as a dinghy. Randomness affects the results of studies because individual responses to drugs vary: for example, a certain antihistamine might work well for your allergies but do nothing for your friend's. The smaller the number of patients enrolled in a study, the higher the effect of individual variations on the aggregate data. As a result, in a small study the researchers can only be sure that the treatment actually did any good if two or more groups show a large difference in response.

With only 250 participants in his study, the small differences Turner saw were statistically insignificant. If he had seen the same effects with 10,000 patients, it would have been clear that echinacea, not chance, was responsible.

But Turner is not the only researcher who has studied echinacea. Coleman and his colleagues found 13 other, similar studies. By pooling the data together in a meta-analysis, they tried to see if echinacea had a statistically significant impact when studied with a larger population. They concluded that it did, both for prevention and for treatment.

Although meta-analyses can be revealing, many researchers and physicians view them with suspicion because they can go wrong in many ways. The echinacea meta-analysis has been criticized for having many such difficulties.

For one thing, in real life, no two studies are ever done in exactly the same way. They use different dosages, different types of patients, and different regimens. The variation is even greater with herbal remedies, where the variety of plant and the way it is prepared can vary dramatically.

"You only can use more-or-less, reasonably comparable studies" in a meta-analysis, says Klaus Linde of the Technical University in Munich, who published a systematic review of echinacea studies. "In our opinion, this was not the case in this study."

Furthermore, some studies are simply better done than others, and including poorly designed studies can skew the results of a meta-analysis. "I think there's a general consensus that many of the early studies of natural remedies were done using study designs and methods that probably are not of the same quality that we would like to see for standard pharmaceutical-type drugs," Turner says. "In my opinion, some of the studies that they chose to include that were large and had a lot of weight in the analysis weren't designed very well."

Coleman says that his group included as many relevant studies as they could find in an attempt to include as much information as possible. He acknowledges that studies with quite different designs were included, but he points out that they conducted sub-analyses that examined only particular types of studies. "Other analyses are perhaps less prone to potential error than ours is," Coleman says, "but ours is less prone to miss something."

Coleman argues that dismissing echinacea on the basis of Turner's study is premature, particularly given that "our meta-analysis shows that the preponderance of the evidence suggests that it may work." He points out that Turner used one species of echinacea, Echinacea angustifolia, when the more commonly used species is Echinacea purpurea, which may be more effective. He also argues that the dosages Turner used were too low to show an effect. "Ultimately, what we're trying to suggest is that more studies should be done."

Turner says he chose Echinacea angustifolia because it was the species originally used as a medicinal in the late 1800s, and he says that there is little reason to think that the two species would act differently. He also says that he used the highest dosage considered safe at the time.

Although one can always imagine other variations that might be tested, Turner says that enough is enough. "Given the available data, we believe it is most reasonable to conclude that echinacea is not useful as a treatment for the common cold," he wrote in a letter to the New England Journal of Medicine. "This conclusion should stand until those who promote, manufacture, and sell these products produce convincing evidence of a clinically meaningful benefit." He is optimistic, however, that as herbal medicines continue to be studied carefully, some of them will prove to be effective.

Linde, despite his skepticism of Coleman's meta-analysis, argues that more research is needed. He says that some studies tentatively suggest that the aerial parts of Echinacea purpurea may shorten colds if taken early in the course of the illness. Furthermore, he points out, people continue to use echinacea frequently, spending $126 million on the herb in the U.S. alone in 2006. It would be nice to know for sure whether they're getting any benefit for their money. 

Hubble's Last Hurrah

Hubble's Last Hurrah

The Skies' Eyes
The Hubble Space Telescope, pictured here during its 4th repair mission, will be serviced a final time in 2008. The upgrades should extend Hubble's operational life through 2013, and its orbit should be stable for another decade or so after that.

If it is true that what does not kill you makes you stronger, the final incarnation of the Hubble Space Telescope may fundamentally change what is known about existence.

After reversing a decision to cancel a shuttle servicing mission to Hubble, NASA is putting the finishing touches on a flight planned for August to overhaul the world's most popular observatory one last time.

The expectations seem giddily high. Astronomers want to use the refurbished telescope to peer back to when the universe was a mere 460 million years old -- a fraction of its current 13.7 billion years. They plan to hunt down supernova explosions to serve as bookmarks in time and space in an attempt to figure out why the expansion of the universe has sped up in the last 4 to 5 billion years or so.

Some scientists are even putting forth most audacious proposals to chemically analyze the atmospheres of planets circling other stars.

Were it not for Hubble's history, the dreams would be far-fetched. Written off as a boondoggle after scientists discovered its misshaped primary mirror, Hubble, outfitted with corrective optics during the first shuttle servicing mission in December 1993, was resurrected and spent the next 14 years making observations of the universe that drove astronomy textbooks into early retirement.

For example, in an ironic tribute to its namesake, the space telescope uncovered evidence that the universe's expansion is speeding up, not slowing down as predicted. Astronomer Edwin Hubble discovered in the 1920s that the galaxies are all flying apart and that the ones farthest away from Earth are flying the fastest.

"We've been able to use Hubble to probe the story farther back in time," said Adam Riess, a highly regarded 36-year-old astrophysicist at Johns Hopkins University in Baltimore, who developed techniques for using supernova explosions to ferret out the universe's steroid-like expansion rate.

Dark Mysteries

The force whipping the universe's spread has been termed dark energy, which is quite distinct from so-called dark matter.

"Dark matter are particles of matter that mostly reside in galaxies. Dark energy is smooth and spread evenly through space. Dark matter we've known about for 80 years or so. Dark energy is something new, only detected 10 years ago," Riess said.

Scientists don't know much about dark energy. But they do know that it is causing the universe to expand 20 percent faster today than it was 5 billion years ago. More data is expected once Hubble is outfitted with a new wide-field camera, one of two new science instruments to be installed by spacewalking astronauts during the upcoming shuttle flight.

The new camera will enable Hubble to detect and image an expanded chunk of the electromagnetic spectrum, with sensitivity spanning ultraviolet to near-infrared radiation. It also greatly increases the amount of information that can be collected during a single observation.

"We can take the same data 70 times faster and with 40 to 50 percent better resolution," said Sandra Faber, an astronomer at the University of California-Santa Cruz, who plans to use the new camera to image the universe's first galaxies.

Riess' study of dark energy hinges on surveys of supernovas. Hubble's new camera is expected to increase their rate of detection by a factor of 2.5, as well as find supernovas that are much farther away, according to a National Science Foundation report that prompted NASA to reinstate the Hubble servicing mission.

"The result would be much tighter constraints on the properties of dark matter," the report concludes.

Back From the Dead

The shuttle flight to Hubble was canceled by former NASA administrator Sean O'Keefe following the 2003 Columbia accident, due to safety concerns. His successor, Mike Griffin, reversed the decision after outside experts concluded a flight to Hubble was not significantly more risky than flying to the International Space Station, which offers shuttle astronauts a safe haven if their ship is too damaged to return to Earth.

To mitigate the risk of flying to Hubble, NASA plans to have a second shuttle at the launch pad ready to mount a rescue mission in case of an emergency.

The mission will be among the most ambitious NASA has attempted. Five spacewalks are planned during the 11-day flight.

In addition to installing the new wide-angle camera, astronauts plan to replace Hubble's corrective optics instrument, which is no longer needed (science instruments installed after Hubble's mirror flaw was discovered are manufactured to precisely match the misshaped glass), with an ultraviolet-sensitive spectrometer that can detect gases which individual light beams have encountered on their journeys from a radiating source to Hubble's eye.

Scientists plan to use the Cosmic Origins Spectrograph (COS) to probe the chemical composition of gas between galaxies for elements such as nitrogen, silicon, aluminum, oxygen, carbon, and iron, all of which somehow evolved from the hydrogen and helium created in the Big Bang. COS also will be used to probe the atmospheres of extrasolar planets, perhaps providing evidence of distant worlds with habitable environments.

A Long To-Do List

Before leaving Hubble, the astronauts will attempt to revive Hubble's visible light camera, which short-circuited last year, and repair a second spectrograph, which failed in 2004. They also plan to replace the observatory's guidance sensors and gyroscopes, which are needed to point and hold the telescope on targets, and install fresh batteries.

Finally, they will wrap Hubble with new layers of insulation and install a docking ring so a booster rocket can latch on at some point in the future to steer Hubble safely toward the atmosphere and its final resting place in the sea.

That won't happen anytime soon. The upgrades should extend Hubble's operational life through 2013, and its orbit should be stable for another 10 years or so after that.

Hubble has defied the odds many times before. Perhaps when another spacecraft locks on to Hubble's new docking port, it will be the shuttle replacement Orion, with a new crew to service the telescope once again.