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Friday, July 18, 2008

New Way To Weigh Giant Black Holes

By measuring a peak in the temperature of hot gas in the center of the giant elliptical galaxy NGC 4649, scientists have determined the mass of the galaxy's supermassive black hole. The method, applied for the first time, gives results that are consistent with a traditional technique.

Astronomers have been seeking out different, independent ways of precisely weighing the largest supermassive black holes, that is, those that are billions of times more massive than the Sun. Until now, methods based on observations of the motions of stars or of gas in a disk near such large black holes had been used.

"This is tremendously important work since black holes can be elusive, and there are only a couple of ways to weigh them accurately," said Philip Humphrey of the University of California at Irvine, who led the study. "It's reassuring that two very different ways to measure the mass of a big black hole give such similar answers."

NGC 4649 is now one of only a handful of galaxies for which the mass of a supermassive black hole has been measured with two different methods. In addition, this new X-ray technique confirms that the supermassive black hole in NGC 4649 is one of the largest in the local universe with a mass about 3.4 billion times that of the Sun, about a thousand times bigger than the black hole at the center of our galaxy.

The new technique takes advantage of the gravitational influence the black hole has on the hot gas near the center of the galaxy. As gas slowly settles towards the black hole, it gets compressed and heated. This causes a peak in the temperature of the gas right near the center of the galaxy. The more massive the black hole, the bigger the temperature peak detected by Chandra.

This effect was predicted by two of the co-authors -- Fabrizio Brighenti from the University of Bologna, Italy, and William Mathews from the University of California at Santa Cruz -- almost 10 years ago, but this is the first time it has been seen and used.

"It was wonderful to finally see convincing evidence of the effects of the huge black hole that we expected," said Brighenti. "We were thrilled that our new technique worked just as well as the more traditional approach for weighing the black hole."

The black hole in NGC 4649 is in a state where it does not appear to be rapidly pulling in material towards its event horizon, nor generating copious amounts of light as it grows. So, the presence and mass of the central black hole has to be studied more indirectly by tracking its effects on stars and gas surrounding it. This technique is well suited to black holes in this condition.

"Monster black holes like this one power spectacular light shows in the distant, early universe, but not in the local universe," said Humphrey. "So, we can't wait to apply our new method to other nearby galaxies harboring such inconspicuous black holes."

These results will appear in an upcoming issue of The Astrophysical Journal. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

Tribe living without numbers

Imagine a life without numbers. It would be tricky to know if your salary has been paid or if a shopkeeper has short-changed you.

But one tribe living in the Amazon rainforest does just fine without them.

The Piraha people have words to exp­ress quantities such as 'some' and 'more' but not individual numbers.

The 300-strong group use one term to quantify things between one and four and another for five or above, researchers found. 'It is often assumed counting is an inn­ate part of human cognition,' said Prof Edward Gibson, of US university MIT.

'This group could learn but it's not useful in their culture, so they've never picked it up.'

The research follows a similar discovery in 2004 by a team of equally intrepid linguists from Columbia University.

They believed the same tribe had words for 'one', 'two' and 'many' only and linked the skill level involved to that of infants, rodents, monkeys and birds.

As hunter-gatherers who rejected any assimilation into mainstream Brazilian culture, they appeared to have no need for a counting system.

But it was also found that they lacked another commonplace skill – drawing.

'Producing simple straight lines was accomplished only with great effort and concentration, accompanied by heavy sighs and groans,' Dr Peter Gordon told journal Science.

Strongest Material Ever Tested

Materials scientists have been singing graphene's praises since it was first isolated in 2005. The one-atom-thick sheets of carbon conduct electrons better than silicon and have been made into fast, low-power transistors. Now, for the first time, researchers have measured the intrinsic strength of graphene, and they've confirmed it to be the strongest material ever tested. The finding provides good evidence that graphene transistors could take the heat in future ultrafast microprocessors.

Jeffrey Kysar and James Hone, mechanical-engineering professors at Columbia University, tested graphene's strength at the atomic level by measuring the force that it took to break it. They carved one-micrometer-wide holes into a silicon wafer, placed a perfect sample of graphene over each hole, and then indented the graphene with a sharp probe made of diamond. Such measurements had never been taken before because they must be performed on perfect samples of graphene, with no tears or missing atoms, say Kysar and Hone.

Hone compares his test to stretching a piece of plastic wrap over the top of a coffee cup, and measuring the force that it takes to puncture it with a pencil. If he could get a large enough piece of the material to lay over the top of a coffee cup, he says, graphene would be strong enough to support the weight of a car balanced atop the pencil.

It's unlikely that graphene's incredible strength will be put to use in such a task. At the macroscopic level of coffee cups and cars, "any material will be full of cracks and flaws," says Kysar. It's at the level of such cracks and flaws that airplane wings and bridge supports fail. "Only a tiny sample can be perfect and superstrong," says Hone.

However, the measurements are yet another demonstration of the remarkable properties of graphene. "We knew graphene was the strongest material; this work confirms it," says Konstantin Novoselov, a fellow at the University of Manchester, who was the first to isolate two-dimensional sheets of the material.

The material's strength is particularly good news for those in the semiconductor industry who hope to make computers faster by developing microprocessors that use graphene transistors. "The main liability concerning the microprocessing industry is strain," says Julia Greer, a materials scientist at Caltech. Not only must the materials used to make transistors have good electrical properties, but they must also be able to survive the stresses of manufacturing processes and the heat generated by repeated operations. The processes used to pattern metal electrical connections onto microprocessors, for example, exert stresses that can cause chips to fail. And, says Greer, the main obstacle to making faster microprocessors is that "the heat is too much for materials to take." Based on measurements of its strength, graphene transistors could take the heat.

Graphene is the basic building block of several other three-dimensional nanostructures made up of carbon, including nanotubes and buckyballs, hollow soccer-ball-shaped molecules. "In theory, a nanotube is rolled-up graphene, so it should have the same strength," says Hone. In reality, however, most nanotubes have tiny flaws--an atom missing here or there. "When you pull on a nanotube," says Hone, it breaks at any site where there's a defect.

The mechanical strength of graphene on the nanoscale could prove useful for applications other than in transistors for microprocessors. The material could, for example, serve as a durable, mechanically operated electrical switch for communications devices including cell phones and advanced radar, says Kysar.

Although most research on nanomaterials has focused on their electrical, optical, and chemical properties, "mechanical properties control more than it might appear," says Greer. Existing databases of materials' strength don't account for differences in strength at the nanoscale. But now, at least, researchers testing the strength of nanomaterials will have a record to shoot for.

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I've always been a big fan of Al Gore...he's been a powerful public figure for my entire political life. My first vote ever was cast for him. So I'm pretty happy to listen when he talks, and very much enjoy what he has to say. But I don't tend to be surprised by what he says. He's had a lot of the same ideas for a long time now.

But today, I am surprised. In a speech in D.C. Al challenged America to produce 100% of it's power from carbon-free sources in ten years.

I'm an EcoGeek, possibly the biggest EcoGeek you know. So I'm optimistic about these things. I know that there are a lot of technologies out there that, if they spring forth from the lab and into widespread use, could make collassal differences in the way we produce power.

But this is a big pill...like, football-sized. The lifespan of a coal-fired power plant is between 30 and 50 years. Power companies build these things with those 30 to 50 years in mind. They aren't going to dismantle them when they're 15 years old without some gigantic form of compensation.

Gore makes only cursory mention of carbon capture and storage technology. I personally believe that the technology and infrastructure necessary to implement CCS on a large scale is not going to happen in less than 10 years. In my opnion, we really are going to have to wait for the coal plants to die rather than figure out how to store their carbon.

I did enjoy the way Gore portrayed the issue though. It's no longer that global warming is the largest catastrophe that man will ever face (his previous strategy.) Now he's focusing the whole suite of problems that can be solved with renewable energy: job creation at home, removal of reliance on other nations for our power, sustainability, poullution and global warming. It's worth noting that we don't burn (much) oil for power, but in two years, we may be filling up at the plug, rather than the pump anyway.

Gore's primary path for getting to carbon neturality, it seems, is carbon taxes. I 100% agree that this is the way to do it. Unfortunately, I don't see very many congress people being too enthusiastic about increasing the price of gasoline more. Obama praised the speech, and said that his candidacy would bring many of these changes (certainly more than a McCain presidency) but didn't endorse, or even mention, the 10-year deadline.

That is probably because the 10-year deadline seems a little insane. Gore's insistence on it's practicality is somewhat puzzling to me. But I certainly don't mind crazy goals. We spend a heck of a lot of money in this country. It'd be nice to spend it on an effort to strengthen the country at the core...rather than weaken itself by over-extension in an attempt to lock up the last little pockets of oil on the planet.

You can read the full text of the speech below.

Ladies and gentlemen:

There are times in the history of our nation when our very way of life depends upon dispelling illusions and awakening to the challenge of a present danger. In such moments, we are called upon to move quickly and boldly to shake off complacency, throw aside old habits and rise, clear-eyed and alert, to the necessity of big changes. Those who, for whatever reason, refuse to do their part must either be persuaded to join the effort or asked to step aside. This is such a moment. The survival of the United States of America as we know it is at risk. And even more – if more should be required – the future of human civilization is at stake.

I don’t remember a time in our country when so many things seemed to be going so wrong simultaneously. Our economy is in terrible shape and getting worse, gasoline prices are increasing dramatically, and so are electricity rates. Jobs are being outsourced. Home mortgages are in trouble. Banks, automobile companies and other institutions we depend upon are under growing pressure. Distinguished senior business leaders are telling us that this is just the beginning unless we find the courage to make some major changes quickly.

The climate crisis, in particular, is getting a lot worse – much more quickly than predicted. Scientists with access to data from Navy submarines traversing underneath the North polar ice cap have warned that there is now a 75 percent chance that within five years the entire ice cap will completely disappear during the summer months. This will further increase the melting pressure on Greenland. According to experts, the Jakobshavn glacier, one of Greenland’s largest, is moving at a faster rate than ever before, losing 20 million tons of ice every day, equivalent to the amount of water used every year by the residents of New York City.

Two major studies from military intelligence experts have warned our leaders about the dangerous national security implications of the climate crisis, including the possibility of hundreds of millions of climate refugees destabilizing nations around the world.

Just two days ago, 27 senior statesmen and retired military leaders warned of the national security threat from an “energy tsunami” that would be triggered by a loss of our access to foreign oil. Meanwhile, the war in Iraq continues, and now the war in Afghanistan appears to be getting worse.

And by the way, our weather sure is getting strange, isn’t it? There seem to be more tornadoes than in living memory, longer droughts, bigger downpours and record floods. Unprecedented fires are burning in California and elsewhere in the American West. Higher temperatures lead to drier vegetation that makes kindling for mega-fires of the kind that have been raging in Canada, Greece, Russia, China, South America, Australia and Africa. Scientists in the Department of Geophysics and Planetary Science at Tel Aviv University tell us that for every one degree increase in temperature, lightning strikes will go up another 10 percent. And it is lightning, after all, that is principally responsible for igniting the conflagration in California today.

Like a lot of people, it seems to me that all these problems are bigger than any of the solutions that have thus far been proposed for them, and that’s been worrying me.

I’m convinced that one reason we’ve seemed paralyzed in the face of these crises is our tendency to offer old solutions to each crisis separately – without taking the others into account. And these outdated proposals have not only been ineffective – they almost always make the other crises even worse.

Yet when we look at all three of these seemingly intractable challenges at the same time, we can see the common thread running through them, deeply ironic in its simplicity: our dangerous over-reliance on carbon-based fuels is at the core of all three of these challenges – the economic, environmental and national security crises.

We’re borrowing money from China to buy oil from the Persian Gulf to burn it in ways that destroy the planet. Every bit of that’s got to change.

But if we grab hold of that common thread and pull it hard, all of these complex problems begin to unravel and we will find that we’re holding the answer to all of them right in our hand.

The answer is to end our reliance on carbon-based fuels.

In my search for genuinely effective answers to the climate crisis, I have held a series of “solutions summits” with engineers, scientists, and CEOs. In those discussions, one thing has become abundantly clear: when you connect the dots, it turns out that the real solutions to the climate crisis are the very same measures needed to renew our economy and escape the trap of ever-rising energy prices. Moreover, they are also the very same solutions we need to guarantee our national security without having to go to war in the Persian Gulf.

What if we could use fuels that are not expensive, don't cause pollution and are abundantly available right here at home?

We have such fuels. Scientists have confirmed that enough solar energy falls on the surface of the earth every 40 minutes to meet 100 percent of the entire world’s energy needs for a full year. Tapping just a small portion of this solar energy could provide all of the electricity America uses.

And enough wind power blows through the Midwest corridor every day to also meet 100 percent of US electricity demand. Geothermal energy, similarly, is capable of providing enormous supplies of electricity for America.

The quickest, cheapest and best way to start using all this renewable energy is in the production of electricity. In fact, we can start right now using solar power, wind power and geothermal power to make electricity for our homes and businesses.

But to make this exciting potential a reality, and truly solve our nation’s problems, we need a new start.

That’s why I’m proposing today a strategic initiative designed to free us from the crises that are holding us down and to regain control of our own destiny. It’s not the only thing we need to do. But this strategic challenge is the lynchpin of a bold new strategy needed to re-power America.

Today I challenge our nation to commit to producing 100 percent of our electricity from renewable energy and truly clean carbon-free sources within 10 years.

This goal is achievable, affordable and transformative. It represents a challenge to all Americans – in every walk of life: to our political leaders, entrepreneurs, innovators, engineers, and to every citizen.

A few years ago, it would not have been possible to issue such a challenge. But here’s what’s changed: the sharp cost reductions now beginning to take place in solar, wind, and geothermal power – coupled with the recent dramatic price increases for oil and coal – have radically changed the economics of energy.

When I first went to Congress 32 years ago, I listened to experts testify that if oil ever got to $35 a barrel, then renewable sources of energy would become competitive. Well, today, the price of oil is over $135 per barrel. And sure enough, billions of dollars of new investment are flowing into the development of concentrated solar thermal, photovoltaics, windmills, geothermal plants, and a variety of ingenious new ways to improve our efficiency and conserve presently wasted energy.

And as the demand for renewable energy grows, the costs will continue to fall. Let me give you one revealing example: the price of the specialized silicon used to make solar cells was recently as high as $300 per kilogram. But the newest contracts have prices as low as $50 a kilogram.

You know, the same thing happened with computer chips – also made out of silicon. The price paid for the same performance came down by 50 percent every 18 months – year after year, and that’s what’s happened for 40 years in a row.

To those who argue that we do not yet have the technology to accomplish these results with renewable energy: I ask them to come with me to meet the entrepreneurs who will drive this revolution. I’ve seen what they are doing and I have no doubt that we can meet this challenge.

To those who say the costs are still too high: I ask them to consider whether the costs of oil and coal will ever stop increasing if we keep relying on quickly depleting energy sources to feed a rapidly growing demand all around the world. When demand for oil and coal increases, their price goes up. When demand for solar cells increases, the price often comes down.

When we send money to foreign countries to buy nearly 70 percent of the oil we use every day, they build new skyscrapers and we lose jobs. When we spend that money building solar arrays and windmills, we build competitive industries and gain jobs here at home.

Of course there are those who will tell us this can't be done. Some of the voices we hear are the defenders of the status quo – the ones with a vested interest in perpetuating the current system, no matter how high a price the rest of us will have to pay. But even those who reap the profits of the carbon age have to recognize the inevitability of its demise. As one OPEC oil minister observed, “The Stone Age didn’t end because of a shortage of stones.”

To those who say 10 years is not enough time, I respectfully ask them to consider what the world's scientists are telling us about the risks we face if we don’t act in 10 years. The leading experts predict that we have less than 10 years to make dramatic changes in our global warming pollution lest we lose our ability to ever recover from this environmental crisis. When the use of oil and coal goes up, pollution goes up. When the use of solar, wind and geothermal increases, pollution comes down.

To those who say the challenge is not politically viable: I suggest they go before the American people and try to defend the status quo. Then bear witness to the people's appetite for change.

I for one do not believe our country can withstand 10 more years of the status quo. Our families cannot stand 10 more years of gas price increases. Our workers cannot stand 10 more years of job losses and outsourcing of factories. Our economy cannot stand 10 more years of sending $2 billion every 24 hours to foreign countries for oil. And our soldiers and their families cannot take another 10 years of repeated troop deployments to dangerous regions that just happen to have large oil supplies.

What could we do instead for the next 10 years? What should we do during the next 10 years? Some of our greatest accomplishments as a nation have resulted from commitments to reach a goal that fell well beyond the next election: the Marshall Plan, Social Security, the interstate highway system. But a political promise to do something 40 years from now is universally ignored because everyone knows that it’s meaningless. Ten years is about the maximum time that we as a nation can hold a steady aim and hit our target.

When President John F. Kennedy challenged our nation to land a man on the moon and bring him back safely in 10 years, many people doubted we could accomplish that goal. But 8 years and 2 months later, Neil Armstrong and Buzz Aldrin walked on the surface of the moon.

To be sure, reaching the goal of 100 percent renewable and truly clean electricity within 10 years will require us to overcome many obstacles. At present, for example, we do not have a unified national grid that is sufficiently advanced to link the areas where the sun shines and the wind blows to the cities in the East and the West that need the electricity. Our national electric grid is critical infrastructure, as vital to the health and security of our economy as our highways and telecommunication networks. Today, our grids are antiquated, fragile, and vulnerable to cascading failure. Power outages and defects in the current grid system cost US businesses more than $120 billion dollars a year. It has to be upgraded anyway.

We could further increase the value and efficiency of a Unified National Grid by helping our struggling auto giants switch to the manufacture of plug-in electric cars. An electric vehicle fleet would sharply reduce the cost of driving a car, reduce pollution, and increase the flexibility of our electricity grid.

At the same time, of course, we need to greatly improve our commitment to efficiency and conservation. That’s the best investment we can make.

America's transition to renewable energy sources must also include adequate provisions to assist those Americans who would unfairly face hardship. For example, we must recognize those who have toiled in dangerous conditions to bring us our present energy supply. We should guarantee good jobs in the fresh air and sunshine for any coal miner displaced by impacts on the coal industry. Every single one of them.

Of course, we could and should speed up this transition by insisting that the price of carbon-based energy include the costs of the environmental damage it causes. I have long supported a sharp reduction in payroll taxes with the difference made up in CO2 taxes. We should tax what we burn, not what we earn. This is the single most important policy change we can make.

In order to foster international cooperation, it is also essential that the United States rejoin the global community and lead efforts to secure an international treaty at Copenhagen in December of next year that includes a cap on CO2 emissions and a global partnership that recognizes the necessity of addressing the threats of extreme poverty and disease as part of the world’s agenda for solving the climate crisis.

Of course the greatest obstacle to meeting the challenge of 100 percent renewable electricity in 10 years may be the deep dysfunction of our politics and our self-governing system as it exists today. In recent years, our politics has tended toward incremental proposals made up of small policies designed to avoid offending special interests, alternating with occasional baby steps in the right direction. Our democracy has become sclerotic at a time when these crises require boldness.

It is only a truly dysfunctional system that would buy into the perverse logic that the short-term answer to high gasoline prices is drilling for more oil ten years from now.

Am I the only one who finds it strange that our government so often adopts a so-called solution that has absolutely nothing to do with the problem it is supposed to address? When people rightly complain about higher gasoline prices, we propose to give more money to the oil companies and pretend that they’re going to bring gasoline prices down. It will do nothing of the sort, and everyone knows it. If we keep going back to the same policies that have never ever worked in the past and have served only to produce the highest gasoline prices in history alongside the greatest oil company profits in history, nobody should be surprised if we get the same result over and over again. But the Congress may be poised to move in that direction anyway because some of them are being stampeded by lobbyists for special interests that know how to make the system work for them instead of the American people.

If you want to know the truth about gasoline prices, here it is: the exploding demand for oil, especially in places like China, is overwhelming the rate of new discoveries by so much that oil prices are almost certain to continue upward over time no matter what the oil companies promise. And politicians cannot bring gasoline prices down in the short term.

However, there actually is one extremely effective way to bring the costs of driving a car way down within a few short years. The way to bring gas prices down is to end our dependence on oil and use the renewable sources that can give us the equivalent of $1 per gallon gasoline.

Many Americans have begun to wonder whether or not we’ve simply lost our appetite for bold policy solutions. And folks who claim to know how our system works these days have told us we might as well forget about our political system doing anything bold, especially if it is contrary to the wishes of special interests. And I’ve got to admit, that sure seems to be the way things have been going. But I’ve begun to hear different voices in this country from people who are not only tired of baby steps and special interest politics, but are hungry for a new, different and bold approach.

We are on the eve of a presidential election. We are in the midst of an international climate treaty process that will conclude its work before the end of the first year of the new president's term. It is a great error to say that the United States must wait for others to join us in this matter. In fact, we must move first, because that is the key to getting others to follow; and because moving first is in our own national interest.

So I ask you to join with me to call on every candidate, at every level, to accept this challenge – for America to be running on 100 percent zero-carbon electricity in 10 years. It's time for us to move beyond empty rhetoric. We need to act now.

This is a generational moment. A moment when we decide our own path and our collective fate. I'm asking you – each of you – to join me and build this future. Please join the WE campaign at wecansolveit.org. We need you. And we need you now. We're committed to changing not just light bulbs, but laws. And laws will only change with leadership.

On July 16, 1969, the United States of America was finally ready to meet President Kennedy’s challenge of landing Americans on the moon. I will never forget standing beside my father a few miles from the launch site, waiting for the giant Saturn 5 rocket to lift Apollo 11 into the sky. I was a young man, 21 years old, who had graduated from college a month before and was enlisting in the United States Army three weeks later.

I will never forget the inspiration of those minutes. The power and the vibration of the giant rocket’s engines shook my entire body. As I watched the rocket rise, slowly at first and then with great speed, the sound was deafening. We craned our necks to follow its path until we were looking straight up into the air. And then four days later, I watched along with hundreds of millions of others around the world as Neil Armstrong took one small step to the surface of the moon and changed the history of the human race.

We must now lift our nation to reach another goal that will change history. Our entire civilization depends upon us now embarking on a new journey of exploration and discovery. Our success depends on our willingness as a people to undertake this journey and to complete it within 10 years. Once again, we have an opportunity to take a giant leap for humankind.

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Amazing Stat: California Uses More Gas than China

Given all the news coverage about the rise of the Chinese economy, you could be forgiven for thinking that the world's most populous country is hogging all the world's resources, while the developed nations are fighting for scraps.

But, at least with transportation fuel, you'd be wrong. California alone uses more gasoline than any country in the world (except the US as a whole, of course). That means California's 20 billion gallon gasoline and diesel habit is greater than China's! (Or Russia's. Or India's. Or Brazil's. Or Germany's.)

That's according to the California Energy Commission's State Alternative Fuels Plan, which was posted online last Christmas Eve (pdf). The whole report makes for some fascinating reading because it's a blueprint for a low-carbon and renewable transportation fuel future. The dominant takeaway: it ain't going to be easy.

One more choice statistic: gasoline usage in California has increased 50 percent, that's 10 6.7 billion gallons, since 1988. Has there been anything close to a commensurate increase in quality of life here to accompany that rise in energy use?

But China's oil thirst is growing -- to almost 20 billion gallons in 2007 -- and perhaps as early as this year, China's 1.3 billion people will overtake California's 37 million people in total gasoline and diesel usage.

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