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Thursday, September 4, 2008

How big can a black hole grow?

Just how big can a black hole grow? Two astronomers reckon they have worked out the answer: colossal black holes with a mass of up to 50 billion suns could be lurking out there – but that's the limit.

Giant black holes sit at the cores of virtually all galaxies, and are thought to have grown from smaller seed black holes that swallowed lots of matter. The biggest well-measured one resides in the galaxy Messier 87 and has the mass of 3 billion suns, a measurement based on the speed of the gas swirling around it.

Even bigger black holes are waiting to be found, say Priya Natarajan of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and Ezequiel Treister of the European Southern Observatory in Santiago, Chile.

In a study to appear in Monthly Notices of the Royal Astronomical Society, the pair examined the "feeding habits" and growth of black holes. They used data from surveys carried out by other teams that observed the X-rays and visible light emitted by matter as it is devoured by black holes. The properties of this radiation can be used to estimate a black hole’s mass and how quickly it is gobbling up its surroundings.

The team analysed how many galactic black holes of various masses were present at each stage in the universe's history. The distribution of masses they found today and in the past can only be explained if there is a limit on how fast black holes can grow, the researchers say.

Ultramassive black hole

Previous studies have also suggested this, and it may be due to the way radiation from infalling matter blasts the black hole's neighbourhood free of additional sustenance. "They self-regulate," says Natarajan. "They never grow beyond a certain mass in any epoch."

Knowing this growth rate allowed them to work out the modern-day size of the biggest known black holes that existed in the early universe. Back then, they are estimated to have had the mass of about a billion suns. According to Natarajan and Treister, a few black holes of this size may have bloated to "ultramassive" size by now, with between 5 and 50 billion times the sun's mass, at the most. Even a black hole at the lower end of this range would be gargantuan – more than 3 times as wide as our solar system.

One ultramassive black hole may already have been spotted 3.5 billion light years away in the galaxy OJ 287, which is thought to harbour a pair of giant black holes circling each other at its centre. The larger of the two has been estimated to be 18 billion solar masses, based on the properties of radiation outbursts from the system, but astronomers disagree on how accurate this is.

Scott Tremaine at Princeton University says that examining the growth history of black holes is important because it appears to be closely tied to the growth of galaxies, including our own. But he cautions that estimating black hole masses from the amount of radiation they give off – as Natarajan and Treister have done – is fraught with uncertainty because a black hole's brightness can vary depending on how much material it eats.

Sun's face virtually spot-free for months

For the last eight months, the sunspots that usually freckle the Sun have virtually disappeared, and nobody knows when they'll return, or how plentiful they'll be. The speed at which the next breakout of spots occurs should reveal how active – and potentially damaging to Earth's satellites and power grids – the new solar cycle will be.

Sunspots are cooler, darker regions caused by the Sun's magnetic field ripping through the star's surface. They vary in number – going from a minimum to a maximum and back to a minimum again – about every 11 years, the same timescale on which the Sun's magnetic poles reverse direction.

Several dozen sunspots can appear every day during periods of maximum solar activity. But only a small handful of sunspots have occurred during all of 2008 to date, suggesting the Sun's activity is now at a minimum.

For a while, it even seemed like August would mark the first time since 1913 that no sunspots were seen for an entire month, according to record-keepers at the National Oceanic and Atmospheric Administration.

But when the final tally was made by the international authority on sunspots, the Solar Influences Data Analysis Center in Brussels, Belgium, one dark blip on 21 and 22 August was large enough to make the count.

Until the spots reappear, researchers say they will not know whether this 11-year solar cycle will bring heavier- or lighter-than-normal activity, or be able to resolve a raging debate about the mechanisms driving solar weather.

Anaemic cycle?

The current absence of sunspots does not necessarily foretell an anaemic cycle of solar activity to come, Leif Svalgaard of Stanford University says. Instead, sunspot watchers are waiting to see how fast the sunspot count starts to climb once they do reappear.

The quicker they return, the more active the solar weather will be for the following decade. "The big [cycles], they start out with a bang. One month, there may be none, the next month they may be all over the place," Svalgaard told New Scientist.

Some space meteorologists predict that the new cycle will be relatively quiet.

The prediction is based on theories suggesting magnetic fields that sink into the Sun near its poles are transported relatively quickly back to the Sun's surface, where they produce sunspots. Since observations show low magnetic field activity at the poles, the idea is that the coming solar cycle will be unspectacular.

'Worst nightmare'

Others theorise that magnetic fields travel for decades deep within the Sun's interior before returning to punch holes in its surface, creating sunspots. These forecasters predict that a strong wave of sunspots is right around the corner.

"As scientists, we're anxiously awaiting [the return of sunspots] because this is really going to help us weed out our different theories," says David Hathaway of NASA's Marshall Space Flight Center in Huntsville, Alabama.

"The worst nightmare is that it's right smack in the middle," Svalgaard says of the sunspots' rate of return. "Then all we know is [the models] are all bad."

Either way, the ramifications could be immense. Periods of strong solar magnetic activity and plentiful sunspots can interrupt communications and overload electricity grids on Earth.

Lengthy periods of low sunspot activity, on the other hand, such as the one between 1645 and 1715 called the Maunder Minimum, have been associated with cooler climate. What's to come in this case? We'll have to wait and see.

Evolution of Your DNA: New Software Traces the Very Code of Life


Human_genome There's a new computer program that knows all about your history - but don't worry, it's not going to report those parking violations or tell your friends what you do at night. It cares about your real history - the evolution of your DNA.

Researchers at Penn State have created the impressively named Gestalt Domain Detection Algorithm-Basic Local Alignment Tool (GDDA-BLAST to its friends - and yes, the team who are tracing the very code of life did just jam in an extra letter to make the name cooler). This software, when it's not hunting Doctor Who, can contrast and compare multiple protein sequences called 'retroelements'. These biological building blocks have existed for a long time, and since they make up half of YOU and many other things (genome-wise) they're pretty useful signposts.

The program can trace the relationships between organisms as varied as bacteria and HIV, producing an tree detailing the evolutionary "distances" between each. It compares every single pair of sequences, and without the subjectivity (not to mention boredom) of human experts performing the same task. Also, the program can operate in the less-than-25%-similar 'twilight zone' where other programs fear to tread.

Even better, these scientists are making the whole thing open-source - so that anyone who wants can trace phylogenetic pathways in their spare time (assuming they have access to a few million dollars of genetics laboratory). Okay, maybe it isn't the sort of thing you'll see people swiping into their iPhones (until society gets good and GATTACA'd up), but the concept of spending years on an amazing program, then just making it free because it's useful, is a great one.

The researchers also report that the program is learning rapidly as it acquires new data, and has already evolved considerably since they first activated it. But we're sure there's no danger in an evolutionary-minded, open-source and web-wide program that can do that.

The Claim: You Get Drunk Faster at High Altitudes

At the national convention last week in the mile-high city of Denver, the New York State Democratic Party warned delegates about the potential effects of drinking alcohol there. “Remember that drinks may go to your head faster than you’re used to in New York,” it said.

It’s an oft-repeated saying, based on the notion that lower oxygen levels at high altitudes impair the ability to metabolize alcohol, leading to quicker absorption and enhanced intoxication. But research suggests otherwise.

In a series of studies for the Federal Aviation Administration, scientists simulated the effects of altitude, performing blood alcohol tests on groups of subjects who drank under ground-level and high-altitude conditions. They found no difference.

In other studies, scientists examined people at altitudes of 12,000 feet and higher and found that such heights, without alcohol, could induce a sort of fatigue that hampers mental and physical abilities. Consuming four drinks at sea level worsened performance, much more so than altitude alone. But combining high altitude and alcohol had only a slightly greater effect on cognitive performance.

Study: Our Mates Look Like Mom and Dad

Men like women who resemble dear old mom, and women like men who look like dear old dad, a computer analysis now shows.

Scientists in Hungary investigated 52 university students and their parents. They also looked at the significant others of the volunteers and the parents of these significant others, for 312 faces total.

The computer analysis of the volunteers' faces revealed that women often resembled their male partner's mother, a finding echoing psychoanalyst Sigmund Freud's legendary "Oedipus complex." This proved especially true when it came to aspects of the lower face, such as lips and jaws.

"Freud may be right in that a strong emotional relationship between mother and son have a strong effect on later life," said researcher Tamas Bereczkei, an evolutionary psychologist at the University of Pécs in Hungary.

There were also significant resemblances between men and their female partner's father, echoing the "Electra complex." This was especially true when it came to proportions of the center of the face, such as how far apart the eyes were or the size of the nose.

The Oedipus and Electra complexes are both named after figures in Greek myth — Oedipus unknowingly killed his father and married his mother, while Electra wanted to kill her mother, who helped plan the murder of Electra's father Agamemnon. Both complexes refer to a subconscious desire of a child for the parent of the opposite sex, often accompanied by hostility to the parent of the same sex.

Bereczkei and his colleagues suggest that people sexually "imprint" on their parents — searching, in the case of heterosexuals, for partners that resemble the parent of the opposite sex. The researchers argue that people are not merely searching for partners who look familiar, as the male volunteers did not go for female partners that resembled their fathers, and the female volunteers did not go for male partners that resembled their mothers.

The researchers conjectured the male volunteers focus on aspects of the lower face since past research suggested that area is related to how feminine women are, while the female volunteers concentrated on the center of the face of men since it sheds light on masculinity. Recent findings are uncovering how specifically faces are important when it comes to deciding mates — for instance, women seem to judge potential mates by how masculine their features are, and also seem to be able to tell which guys might be interested in becoming fathers just by looking at their faces.

Since inbreeding has both costs and benefits in terms of reproduction, the researchers conjecture sexual imprinting might have evolved to help people as a compromise to choose mates with a moderate degree of genetic similarity, who resemble one parent but not the other.

Bereczkei suggested this effect might be "even stronger between spouses belonging to different races, counterbalancing the other differences in cultural background." He also conjectured that when it comes to sexual orientation, "I expect homosexual people to behave in the same manner than heterosexuals and use parental models."

Of course, Bereczkei stressed that many factors go into choosing a mate besides the face, such as status, age and so on. "An investigation of interrelationships among these features would be a very interesting research area in future," he said. "We would like to study those specific circumstances and conditions that make similarity crucial, or at least especially important, in mating. It is possible, and our former studies suggest this, that a strong emotional bond between parent and child promotes the shaping of parental model."

To further explore their findings, Bereczkei and his colleagues plan to test volunteers with composite faces made from merging the volunteer's own face with an average face. "We wonder if these people will recognize 'their own' face and choose them as potential partner," he said.

Future research could also investigate to what degree a person's cultural background influences this effect. Another direction scientists could pursue is whether this effect is limited to mate choice, or whether it encompasses "other phenomena like friendships," Bereczkei said.

Doomsday Claims: Large Hadron Collider To Hit The Road


Critics who say the world's largest atom-smasher could destroy the world have brought their claims to courtrooms in Europe and the United States - and although the claims are getting further consideration, neither court will hold up next week's official startup of the Large Hadron Collider.

The main event took place today in Honolulu, where a federal judge is mulling over the federal government's request to throw out a civil lawsuit filed by retired nuclear safety officer Walter Wagner and Spanish science writer Luis Sancho.

Meanwhile, legal action is pending as well at the European Court of Human Rights in Strasbourg, France. Last week, the court agreed to review doomsday claims from a group of professors and students, primarily from Germany and Austria. However, the court rejected a call for the immediate halt of operations at the LHC.

What it's all about
In the U.S. as well as the European lawsuit, the plaintiffs claim that those involved in the particle collider's operation have not adequately addressed the idea that the LHC could create globe-gobbling microscopic black holes or other catastrophes such as matter-wrecking strangelets or magnetic monopoles. They're calling for further safety reviews to be conducted.

The defendants - including the U.S. Department of Energy as well as Europe's CERN particle-physics center - say such fears already have been knocked down in a series of safety reports. The reports, drawn up by leading researchers in high-energy physics, note that cosmic-ray collisions are many times more energetic and prevalent than the collisions expected at the LHC. If the LHC were capable of creating cosmic catastrophes, they would already have been seen many times over in the wider universe, even in the unlikeliest circumstances, the researchers say.

Past "big-bang machines" have faced similar legal challenges, but the worries are emerging anew because the LHC will smash protons together at energies seven times higher than the current world record, held by the Tevatron at Fermilab in Illinois.

Physicists hope to gain new insights into mysteries of the universe ranging from dark matter to supersymmetric particles. The main quarry is an as-yet-undetected subatomic particle called the Higgs boson, also known as the "God Particle." The Higgs boson is the only fundamental particle predicted by current theory that has not yet been found. If it does not exist, that would add weight to alternative theories that depend on extra dimensions of space-time.

Theorists say the LHC could create microscopic black holes - or, more accurately, subatomic knots of ultra-concentrated energy - only if there are extra dimensions. Current theory also dictates that these knots would unravel instantly. The LHC's critics take issue with that particular claim.

In any case, the collider won't be in a position to create any type of black hole for months. The scheduled Sept. 10 turn-on would circulate only one beam of protons around the LHC's 17-mile-round ring at low energy. The first low-energy collisions won't occur until at least a month from now, and the device won't achieve its top collision energy until next year. That's why the courts are not rushing to rule on the critics' claims.

What's happening in court
Both sides in the federal lawsuit contributed to a flurry of filings in the days before today's hearing in District Judge Helen Gillmor's Honolulu courtroom.

The federal government's attorneys, representing the Energy Department, wanted Gillmor to dismiss the suit or render a summary judgment against Wagner and Sancho - on the grounds that the suit's outcome won't affect operations at the European collider, and that the plaintiffs missed their deadlines for legal filings.

In response, the plaintiffs insisted that their challenge was timely and said the defendants' past assurances did not ease their concerns about the safety issues. They called for the case to continue toward trial, with a tentative date of June 2009 already scheduled.

In the next legal volley, Bruce Strauss, who was the Energy Department's associate program manager for the LHC construction project, took aim at Wagner's credentials as well as his arguments. Strauss wrote that assessing the LHC's safety would "require competency in the field of high-energy physics, not health physics or nuclear medicine." Strauss also questioned Wagner's claims about his role in research, citing recent searches of scientific literature.

Strauss said that the federal lawsuit would have no effect on LHC operations because the federal role in building the collider ended a while ago. He said federal funds were now slated to go only toward supporting research activities at the LHC, to the tune of $10 million a month.

On the safety issue, Strauss said CERN's recent report, which was reviewed by outside experts, covered all the realistic scenarios for out-of-control black holes as well as the other doomsday scenarios - and he pointed out that experts at the American Physical Society recently endorsed the report's conclusions. Two Nobel laureates (Sheldon Glashow and Frank Wilczek) as well as a prominent Harvard physicist (Richard Wilson) have also taken the government's side as friends of the court.

Wagner responded to the government's volley just before today's hearing with yet another round of documents. He contended that the LHC would search for strangelets, insisted that yet-to-be-published research "absolutely refutes" claims that the LHC is safe and complained about Strauss' "ad hominem" attacks - while adding a little hominem of his own. For example, Wagner said Strauss once was searching for evidence of magnetic monopoles himself and was "apparently rankled that my work was successful, while his was not."

If this sounds to you like a blizzard of documents, you're not alone. At today's hearing, Judge Gillmor took both sides to task for filing so many disjointed documents and for failing to follow the local rules of the court, Justice Department spokesman Andrew Ames told me. (I've left a phone message with Wagner to get his side of the story.)

Gillmor took the case under advisement and will decide whether or not to dismiss the case at a later, not-yet-determined time. If the case goes forward, the next step would be to consider the plaintiffs' requests for a preliminary injunction against LHC operations as well as for a summary judgment against CERN.

Will the judge weather yet another storm of paperwork? Maybe not. "She doesn't want any more filings without her permission," Ames told me.

Update for 6:50 p.m. ET Sept. 3: In the wake of Tuesday's 55-minute hearing, Judge Gillmor agreed with the federal government's claim that it is immune from any legal action based on European legal documents (specifically, the European Council's Precautionary Principle and the European Commission's Science and Society Action Plan).

She also denied the request to enter a friend-of-the-court brief on behalf of the three physicists because she received no legally admissible evidence (such as an affidavit) that the physicists were actually involved in the filing

Museum 'cocoon' prepares to open

The Darwin Centre Phase Two is designed around an iconic eight-storey "Cocoon", encased within a glass atrium.

The temperature-controlled Cocoon will house 20 million of the museum's 34 million plant and insect specimens, and laboratories for up to 200 researchers.

Visitors will watch these scientists in action cataloguing rare specimens, when the centre opens in September 2009.

Dr Michael Dixon, director of the Natural History Museum, said: "The Darwin Centre Phase Two will be a landmark new building that will allow visitors to explore the natural world in an exciting and innovative way - truly putting our science on view for the first time.

"It is the only place in the UK where visitors can interact daily with natural science experts, seeing how the collections are helping us to address issues such as the quality of our air, the causes of disease and the maintenance of delicate ecosystems around the world."

Safe from attack

Inside the 'Cocoon' - artist's impression
The top floor will become a public gallery, featuring interactive exhibits

The second phase of the Darwin Centre is the most significant development to the Natural History Museum since it moved to South Kensington in 1881.

The £78m building, designed by C F Moller Architects, and built by HBG Construction, links the historic Waterhouse building with the existing Darwin Centre Phase One and the museum's gardens.

Phase One, which opened in September 2002, houses the museum's collection of 22 million specimens stored in spirit, including the famous giant squid, affectionately known as Archie.

Phase Two is designed to safeguard the museum's dry collections - some 28 million insects and six million plant specimens - of which 20 million will be moved in over the next 12 months.

The 30cm-thick cocoon wrapped in silk lines not only looks stunning, it also has a practical purpose - to protect the museum's delicate collections from attack by pests.

The threat of infestation comes from so-called "museum beetles", commonly known as carpet beetles, which are capable of munching through insect body armour.

Schizodactylusm
The dry collection includes 28 million insects, such as Schizodactylusm
"If you are an organism who likes to eat dead insects, then the Darwin Centre is the finest restaurant in the world," said Paul Bowers, the museum's public offer project director.

To guard against invaders, the temperature within the "silk bubble" will be restricted to 17 Celsius, while the walls and ceilings will be kept bare, to prevent any hidden infestations.

The humidity will be a constant 45% to ensure the longevity of historic specimens, such as the original cocoa plant brought from Jamaica by Dr Hans Sloane in 1689, which inspired the first recipe for drinking chocolate.

Buried within more than 3km of cabinets are rare gems collected by Charles Darwin on the voyage of the Beagle, and by Sir Joseph Banks, who accompanied Captain James Cook on his first great expedition.

Science in action

Scientists at work within the Cocoon
Visitors will observe and interact with the museum's 200 working scientists

The new centre is a working research facility for about 200 scientific staff at any one time, including visiting researchers from some of the 70 countries around the world with whom the museum has affiliations.

Through special glass screens, visitors to the museum will be able to view these scientists in action, creating specimen slides, and classifying species, by a technique known as "DNA barcoding".

Understanding the unique physiology of these species will help scientists to tackle urgent ecological problems, such as how climate change is affecting biodiversity.

Mosquito species studied within the museum are helping scientists to develop better controls for malaria, while the forensic identification of crop pests will help to secure global food supplies.

Neil Greenwood, programme director, Darwin Centre Phase Two, said: "The museum's botany and entomology specimens are vital for research into disease, climate change and threats to the Earth's biodiversity.

The Attenborough theatre
The Attenborough theatre will host public debates on topical science issues

"The controlled conditions within Darwin Centre Phase Two will keep the collections safe for future generations of scientists and visitors."

Nature-lovers will be encouraged to examine botanical specimens "hands-on", with interactive exhibits regularly updated to reflect the changing research that is taking place within the laboratories.

Guests will also be invited to take part in audience debates about issues facing the natural world, in a new live communications space called the David Attenborough Studio.

Affordable, Powerful Electric Scooters Coming Soon


8 Reasons Why BioPlastic is Worse than Regular Plastic

Written by Hank Green

So we're all getting pretty darned familiar with the arguments for and against biofuels. But what about bioplastics? Since we can, theoretically, do anything with corn that we can do with petroleum, wouldn't it be better to do it with corn?

Well, not necessarily. BioPlastics are a mixed bag, and considerably more complicated than biofuels. Mostly, this is because there are about two dozen different ways to create bioplastic, and every one has different properties and capabilities.

  1. Why make stuff out of it when you can eat it? There are lots of hungry people in the world, and it seems a little odd to be making disposable cups out of the stuff when it could be being eaten. Though bioplastic definitely isn't causing an increase in the price of food, it's not impossible to imagine it.
  2. You can't always recycle it. Because bioplastics come in dozens of varieties, there's no way to make sure you're getting the right chemicals in the recycling vat. And, in general, the solution is compost instead of re-entering the supply stream.
  3. It could make plastic recycling impossible. Even worse than not being recyclable itself, if it creeps into the recycling stream (which is likely, since it doesn't look any different) it can introduce new chemicals that make the final recycled product weaker or even unusable.
  4. Compostable doesn't mean compostable. If you toss a bioplastic fork into your compost and assume it'll be dirt in a few months, you'll be sorely disappointed. While bioplastic is (sometimes) compostable, it requires high intensity, high heat commercial composting.
  5. It's never made from organic corn, and generally made from genetically modified corn. And while EcoGeek doesn't have a problem with genetic modification, many other environmentally aware people do.
  6. It makes low quality plastic. Instead of solving the problem of the disposable society, bio-plastics generally can only be made into disposable items. They're having problems even making transparent bioplastic that's strong enough to hold water for a few months.
  7. It's good marketing, but bad honesty. It's very easy to have bioplastic cups or bags or forks. But it's very difficult to figure out what that means. Because there are so many different types of bioplastic, you never really know what you're getting into. Maybe it's compostable, maybe it's not. Maybe it's recyclable, maybe it's not.
  8. What's wrong with storing carbon in landfills? Plastic has gotten a bad rap, for poisoning babies and strangling sea lions. But if it is used properly and ends up in the landfill, I don't see what the problem is. Creating durable products with petroleum is certainly much preferred to burning it. And while plastics factories are big polluters, bio plastics factories though better, don't get us clean either.

None of that is to say that bioplastics might not reign supreme some day, they certainly have advantages as well. They're infinitely producible and safer to burn. But until a durable, recyclable and cheap option starts to win this crazy format war, I'm staying away.

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For Gustav-Level Outages, Cities Tap Hybrid Buses for Power

By Joe Pappalardo
Secretary Michael Chertoff called this weekend’s evacuation measures involving charter and school buses in the New Orleans area a success, but BAE Systems may soon leverage military research to tap emergency power from hybrid-electric bus fleets for cities like San Francisco. (Photograph by Mike Lutz/DHS via Getty Images)

The reinforced levees held, battle-worn residents evacuated, and Hurricane Gustav faded over the Gulf Coast this Labor Day weekend with just one glaring lesson of Katrina left unfulfilled: Storm survivors need more emergency power.

In a stroke of good timing by city planners and bus manufacturers as approximately 1 millions homes and business fought to recover power throughout Louisiana and Mississippi, hybrid-electric bus fleets were beginning plans to retrofit to provide electricity during emergencies. Cities are already buying these vehicles because they reduce fuel costs and air pollution, but as the buses generate more power and manage it better with onboard computers, San Francisco and other trailblazing cities could become models for the hidden power of mass transit to disaster-prone urban centers like New Orleans, which has only restocked on biodiesel buses since Katrina.

Researchers at BAE Systems, a major vendor of municipal hybrid buses, are leveraging research done for the military to pitch cities on tapping power from mass transit buses. “If you’re going to have these power plants rolling around, it would be good to have them do something when they are not rolling around,” says Sean Bond, president of BAE’s Platform Solutions group. “The primary demand [for hybrid buses] was emissions reduction, and that has morphed into preventing greenhouse gasses and fuel savings. Another unintended consequence is the ability to provide power off the vehicle.”

Diesel-powered engines in hybrid electric buses store energy in batteries and use software to determine where and when extra power is needed, such as when a bus climbs a hill. These technologies could serve as the basis of mobile generators. However, it will take more than extension cords to make the scheme work. City buses run off DC power, but the electric grid uses AC at a different amplitude and frequency, so a converter is needed to use vehicles to connect to a power distribution panel.

The U.S. Army will power its next generation vehicles with hybrid power technology, but they are also planning to export power from the vehicles when they are not operating in the field. (The Army is also considering instilling the ability to export power from its current fleet of Mine Resistant Ambush Protected vehicles.) The Army uses a suitcase-size device called an Exportable Power Inverter to tap an armored vehicle’s supply of DC power for use on applications that run on AC power. In civilian disaster response, these converters could be installed on the buses, kept at the sites of vital facilities or included in the deployment kits of first responders. New buses could be built with outlets in place, while current fleets would need a retrofit in order to export power.

Diesel-powered engines in hybrid-electric buses provide energy that is stored in batteries, with software that determines where and when the extra power is needed, such as when a bus climbs a hill. BAE’s newest buses, expected to reach full rate production next year, produce 200 kilowatts when the engine speed is at 2300 rpms. BAE, using data of power consumption from national surveys, estimate a single city bus could provide power to 36 households for a full day or a 12,400 sq.-ft. hospital for 22 hours, on a single tank of diesel gas.

Ironically, cities with fleets of hybrid buses tend to be the places that already have the best contingency-power plans and generators. Still, having additional sources of power can only improve a city’s disaster planning. In 2006 San Francisco city officials chose to buy diesel electric buses in part because they could power command centers and move stalled electric vehicles like streetcars from intersections, according to Marty Mellera, the chief of green programs for the city’s transit authority. The buses are not yet ready to provide emergency power, but Mellera says planning with first responders is well underway.

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Why Hurricane Gustav Didn't Become a Monster

Willie Drye
forNational Geographic News

Hurricane Gustav had the potential to become a monster hurricane last Saturday, but two factors intervened to keep it from intensifying. The hurricane's passage over western Cuba "roughed it up" just enough so that the storm's eye partly deteriorated, said Jeff Masters, director of the private forecasting service Weather Underground in Ann Arbor, Michigan.

And upper-level winds—known as wind shear—were just strong enough to keep the hurricane from quickly regaining power over the very warm waters of the Gulf of Mexico, he said.

The hurricane struck Cuba Saturday with peak winds of about 150 miles (241 kilometers) an hour.

"If the shear had been [a little weaker], it would have survived the crossing of Cuba without undergoing a major disruption," Masters said.

"It would have intensified into a Category 4 hurricane and been a disaster [for the U.S.] We got lucky." (See photos of Gustav barreling into the Gulf.)

Category 4 hurricanes have winds ranging from 131 to 155 miles an hour (211 to 249 kilometers an hour).

Losing Steam

When a disrupted Gustav crossed an area of very warm and deep water in the Gulf of Mexico known as the Loop Current, it was not able to restoke its energy.

Once it was past the Loop Current, Gustav entered cooler, shallower water closer to the Gulf Coast and began losing power.

The hurricane came ashore in Louisiana yesterday morning as a strong Category 2 storm with winds of 110 miles (177 kilometers) an hour.

Gustav was just below the threshold of being classified as a major hurricane with winds of 111 miles (179 kilometers) an hour.

Still, Hurricane Gustav provided a severe test of the repaired levee system in New Orleans.

The storm surges caused water to slosh over the Industrial Canal levee in downtown New Orleans—a levee that failed during disastrous Hurricane Katrina in 2005 but did not break under Gustav.

"That told us that the levee system is improved," Masters said.

But Gustav's power did not fully test the level of protection the levees were designed to provide.

The U.S. Army Corps of Engineers, which has been repairing the levees since Katrina, has said the structures will withstand the storm surge from a Category 3 hurricane.

"They weren't tested to the full level that the Corps has advertised that they've done," Masters said. "We don't know if they will withstand a Category 2 or 3."

(Related: "New Orleans' Rebuilt Levees 'Riddled With Flaws'" [May 6, 2007].)

100 Percent Better

The storm system hugged the Louisiana coast after it made landfall in Cocodrie, a small town on the Gulf Coast about 70 miles (113 kilomters) southwest of New Orleans.

Felix Navejar, a meteorologist at the National Weather Service office in Lake Charles, Louisiana, said southwestern Louisiana fared much better from Gustav than it did three years ago during Hurricane Rita.

Rita was a Category 3 hurricane when it made landfall near the Louisiana-Texas border in September 2005.

"We're 100 percent better than Rita," Navejar said this morning. "It looks really good here—maybe one power outage, but nothing major."

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