Science News: Groups at Harvard and the University of Queensland in Brisbane, Australia, have designed and built a quantum computer to simulate and calculate the behavior of a molecular, quantum system.
The simulation mimics reality exactly.
Monthly Archives: January 2010
NRC raises questions over sale of helium reserve
Science: In 1996, the US Congress decided to sell the 1 billion cubic meters of gaseous helium—specifically the heavier isotope, helium-4—that the country had stockpiled.
But conditions it imposed on the sales are keeping the price of helium artificially low and encouraging waste of a substance indispensable for numerous scientific and technological applications, says a National Research Council report released last week.
Related link
Selling the nation’s helium reserve NRC report
China leads world in research growth
FT.com: China has experienced the strongest growth in scientific research over the past three decades of any country, according to figures compiled for the Financial Times, and the pace shows no sign of slowing.
Jonathan Adams, research evaluation director at Thomson Reuters, said China’s “awe-inspiring” growth had put it in second place to the US—and if it continues on its trajectory it will be the largest producer of scientific knowledge by 2020.
What’s producing methane on Mars?
Nature: The surprising discovery of methane in Mars’s atmosphere could be a sign of life there. Researchers are now working out how to find its source, reports Nature‘s Katharine Sanderson.
National Ignition Facility reaches 1 megajoule
Physics Today: The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL), which is at the heart of the stockpile stewardship program to maintain the reliability of US nuclear weapons without conducting nuclear underground tests, has successfully delivered more than 1 megajoule of laser energy to a target in a few billionths of a second.
This is about 30 times the energy ever delivered by any other group of lasers in the world. In the near future it’s only competitor will be NIF’s clone, Megajoule in France, which is still under construction.
Composite photo shows all three floors containing the 132-ton, 10-meter diameter target chamber. Diagnostic instruments will be attached to the round hatches.
Credit:Jacqueline McBride/LLNL
“This accomplishment is a major milestone that demonstrates both the power and the reliability of NIF’s integrated laser system, the precision targets and the integration of the scientific diagnostics needed to begin ignition experiments,” said NIF Director Ed Moses. “NIF has shown that it can consistently deliver the energy required to conduct ignition [fusion] experiments later this year.”
A demonstration
In order to demonstrate fusion, the energy that powers the Sun and the stars, NIF focuses the energy of 192 powerful laser beams into a pencil-eraser-sized cylinder containing a tiny spherical target filled with deuterium and tritium, two isotopes of hydrogen.
Inside the cylinder, the laser energy is converted to x rays, which compress the fuel until it reaches temperatures of more than 93 million °C and pressures billions of times greater than Earth’s atmospheric pressure.
The rapid compression of the fuel capsule forces the hydrogen nuclei to fuse and release many times more energy than the laser energy that was required to initiate the reaction.
The NIF laser system began firing all 192 laser beams onto targets in June 2009.
In order to characterize the x ray drive achieved inside the target cylinders as the laser energy is ramped up, these first experiments were conducted at lower laser energies and on smaller targets than will be used for the ignition experiments. These targets used gas-filled capsules that act as substitutes for the fusion fuel capsules that will be used in the 2010 ignition campaign. The 1 MJ shot represents the culmination of these experiments using an ignition-scale target for the first time.
A new direction
The next step is to move to ignition-like fuel capsules that require the fuel to be in a frozen hydrogen layer (at 19 Kelvin or −218 °C) inside the fuel capsule. NIF is currently being made ready to begin experiments with ignition-like fuel capsules in the summer of 2010.
NIF, the world’s largest laser facility, is the first facility expected to achieve fusion ignition and energy gain in a laboratory setting.
Paul Guinnessy
Can the US prevent a WMD attack?
NPR: Chances are better than ever that terrorists will unleash a chemical or biological weapon in the next three years—that was the finding of the Commission on the Prevention of Weapons of Mass Destruction Proliferation and Terrorism a year ago. This week, the commission issues a report card on progress in preventing such a disaster.
The pros and cons of medical radiation
NYTimes.com: Americans today receive far more medical radiation than ever before. The average lifetime dose of diagnostic radiation has increased sevenfold since 1980, and more than half of all cancer patients receive radiation therapy. Without a doubt, radiation saves countless lives, and serious accidents are rare.
But patients often know little about the harm that can result when safety rules are violated and ever more powerful and technologically complex machines go awry. To better understand those risks, the New York Times has examined thousands of pages of public and private records and interviewed physicians, medical physicists, researchers and government regulators.
It found that while this new technology allows doctors to more accurately attack tumors and reduce certain mistakes, its complexity has created new avenues for error—through software flaws, faulty programming, poor safety procedures, or inadequate staffing and training. When those errors occur, they can be crippling.
Spirit lives on Mars
Physics Today: After six years of successfully exploring Mars, NASA has given up trying to drive the Spirit Mars rover out from where it got stuck several months ago.
Spirit‘s twin rover Opportunity still remains free and is currently heading towards a large crater called Endeavor.
End of the road for Spirit (credit: NASA/JPL)
In the next few weeks, Spirit will be to optimized to survive the severe Martian winter so that it can operate as a stationary science platform for years to come. The two rovers were originally designed to last just 90 days, and have driven more than 12 miles across the surface.
“Spirit is not dead; it has just entered another phase of its long life,” said Doug McCuistion, director of the Mars Exploration Program at NASA headquarters in Washington. “We told the world last year that attempts to set [Spirit] free may not be successful.”
Stuck in sand
Ten months ago, as Spirit was driving south beside the western edge of a low plateau called Home Plate, its wheels broke through a crusty surface and churned into soft sand hidden underneath.
After Spirit became embedded, the rover team crafted plans for trying to get the six-wheeled vehicle free using its five functioning wheels—the sixth wheel quit working in 2006. In November, another wheel quit working, making a difficult situation even worse.
Although some of the more recent efforts to unstick the rover looked promising, the coming winter mandates a change in strategy.
This animation from Spirit‘s front camera shows the motion during five drives on 14-23 January 2010 to try and get the rover out of the sand. Credit NASA/JPL
At Spirit‘s current location it is mid-autumn. Winter will begin in May. Solar energy is declining and expected to become insufficient to power further driving by mid-February. The rover team plans to use those remaining potential drives for improving the rover’s tilt. Spirit currently tilts slightly toward the south. The winter sun stays in the northern sky, so decreasing the southward tilt would boost the amount of sunshine on the rover’s solar panels.
“We need to lift the rear of the rover, or the left side of the rover, or both,” said Ashley Stroupe, a rover driver at JPL. “Lifting the rear wheels out of their ruts by driving backward and slightly uphill will help. If necessary, we can try to lower the front right of the rover by attempting to drop the right-front wheel into a rut or dig it into a hole.”
At its current angle, Spirit probably would not have enough power to keep communicating with Earth through the Martian winter. Even a few degrees of improvement in tilt might make enough difference to enable communication every few days.
“Getting through the winter will all come down to temperature and how cold the rover electronics will get,” said John Callas, project manager at JPL for Spirit and its twin rover, Opportunity. “Every bit of energy produced by Spirit’s solar arrays will go into keeping the rover’s critical electronics warm, either by having the electronics on or by turning on essential heaters.”
A stationary state
Even in a stationary state, Spirit can continue doing scientific research.
“There’s a class of science we can do only with a stationary vehicle that we had put off during the years of driving,” said Steve Squyres, a researcher at Cornell University and principal investigator for the two Martian rovers.
One stationary experiment Spirit has begun studies tiny wobbles in the rotation of Mars to gain insight about the planet’s core. This requires months of radio-tracking the motion of a point on the surface of Mars to calculate long-term motion with an accuracy of a few inches.
“If the final scientific feather in Spirit‘s cap is determining whether the core of Mars is liquid or solid, that would be wonderful,” said Squyres.
Tools on Spirit‘s robotic arm can study variations in the composition of nearby soil, which has been affected by water. Stationary science also includes watching how wind moves soil particles and monitoring the Martian atmosphere.
Paul Guinnessy
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A moldable gel that can heal itself
Science News: Pulling yourself back together after a breakup can be tough to do. But a new hydrogel has no trouble. Using little more than water, clay, and a new, designer compound, scientists have created a moldable gel that is both strong and can heal itself in seconds when split in two. The gel may advance efforts in tissue engineering and environmentally friendly chemistry.
Science under Barack Obama
BBC Radio 3: Philip Dodd presents an edition of Night Waves dedicated to assessing science in America under Barack Obama.
One year ago today Barack Obama’s inaugural address pledged that “We will restore science to its rightful place…our time of standing pat, of protecting narrow interests and putting off unpleasant decisions – that time has surely passed.”
These words brought delight to many in the science world and provoked anger amongst others. Under President Bush science in America had become a hotly contested subject with accusations of inappropriate political interference, skepticism of climate change science was widespread and federal funding for stem cell research restricted on religious grounds.
Obama had made many science-related promises on the campaign trail, so a year on how comfortably does science sit in the American landscape?