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A strontium clock that loses one second every 200 million years

An atomic clock that is based on thousands of strontium atoms trapped using lasers and loses only 1 second in more than 200 million years has been demonstrated by researchers at the Joint Institute for Laboratory Astrophysics, a collaboration between the US National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder. It is more precise than the current US time standard, which is based on a "fountain" of cesium atoms and accurate to 1 second in 80 million years.

Super-precise atomic clocks are used to synchronize global telecommunications networks and deep-space communications, as well as military navigation and positioning.

The new clock uses lasers to trap thousands of ultra cold strontium atoms in an optical lattice. The strontium atoms absorb very precise frequencies of optical light. This allows researchers to use them to keep time. (A strontium clock such as the one demonstrated ticks 430 million times each second.) The NIST standard uses microwaves, which have lower frequencies (and hence lower precision).

However, the strontium clock is the not the world's most precise. That honor goes to an experimental design based on a single mercury ion. It is supposedly so accurate that it loses only 1 second in 400 million years.

But strontium-based clocks have some advantages, according to scientists.

"A large ensemble of neutral atoms offers an enhanced clock signal strength that will make them more precise than a single trapped ion based clock," said Jun Ye, who is the leader of the scientific team that developed the new strontium clock.

So what is next?

"We will continue to enhance the clock precison and the clock accuracy," said Ye. "At this point, it's likely that the performance improvement by another factor of 10 will come relatively quickly."

For more information, go to the Jun Ye's research page on strontium clocks:

A solar system like ours is found

We continue to see that our place in the universe is not special at all. This past week, astronomers announced that they had found a solar system that looks surprisingly like the one we live in -- except that it lies thousands of light years away.

Astronomers report in the latest issue of Science that they have found two planets across the galaxy, around a reddish Sun-like star which lies 5,000 light years away. They saw two planets â'' one about two thirds the mass of Jupiter and one about 90 percent as massive as Saturn â'' orbiting the star in a manner reminiscent of our own solar system. Between the star and these planets may lie Earth-like planets, say the scientists, it's just that our telescopes are not yet powerful enough to see them.

This is a major scientific â'' and philosophical â'' milestone, which continues the revolution started by Copernicus and Kepler and Galileo, in which Earth and then the Sun lost their special place as the center of the universe.

It was only in 1995 that the first planet beyond the Solar System was observed. Since then, astronomers have found about 260. Most of these were found by an indirect method, inferring a planet's existence from the gravitational wobble it introduced into the orbit of the parent star.

Last November, NASA astronomers said they had seen a planetary system with five planets surrounding a nearby star, 55 Cancri, in the constellation of Cancer. But the solar system just found -- which goes by the unwieldy name, OGLE-2006-BLG-109 -- is the most analogous to our own.

More details, including how the planetary system was discovered, can be found at:

Mars may have been too salty for life as we know it

Our neighboring planet, long a favorite of those who believe in extraterrestrials, may have been too salty for life as we know it, according to latest evidence gathered on Mars by one of the NASA rovers, Opportunity.

Speaking at the annual meeting of the American Association for the Advancement of Science currently underway in Boston, Harvard professor Andrew Knoll, who is a member of the NASA rover scientific team, said the high concentration of minerals on any Martian water would have made it very salty. Previous research had shown that Martian water would have been quite acidic as well.

"There are limits to the way microorganisms can adapt to tolerate acidity and salinity,' Knoll said.

On Earth, there are no environments that have a combination of such high acidity and salinity and which harbor life, he pointed out.

For images and information about NASA's Mars rovers,

Spirit and Opportunity, go to

Science Debate 2008 - it's not too late

The Union of Concerned Scientists has organized a call for a U.S. â''science debate.â''

UCS is working with all three National Academies, the American Association for the Advancement of Science, and scores of universities nationwide to hold Science Debate 2008â''an initiative to hold a presidential science policy debate in April in Philadelphia before the Pennsylvania primary.

There couldnâ''t be a better place. Philadelphia was the home of one of the first electrical engineersâ''Ben Franklin. It was the birthplace of many of the oldest computers ever built.

And there couldnâ''t be a better time. Some of the biggest political questions facing the United States either are scientific issues themselves, or cannot be settled without good science.

Global warming, stem-cell and other medical research, space exploration, wireless communications, food and water safety, the digital divideâ''thereâ''s no shortage of things to ask the candidates about.

Legislation introduced last year would shield the U.S. Surgeon General from political interference. Where do the candidates stand?

Which candidates would restore the Office of Technology Assessment?

Should the head of the White House Office of Science and Technology Policy report directly to the president?

Would the candidates increase or decrease funding at the National Science Foundation and National Institutes of Health? And what would their priorities be? What about science education in public schools?

The UCS has a petition calling for the science debate here.

Sadly, a moderator would have to ask about some of the most basic matters of science factâ''for example, â''Do you believe in evolution?â''

When that question was asked in an early Republican presidential debateâ''one of the few times a scientific issue has been raised so farâ''three of the ten candidates then running said they did not. Thankfully, the moment has (of course) been preserved on YouTube.

One of those candidates, Mike Huckabee, is still in the race, so if the Science Debate should come off, I know what Iâ''d like the first question to be.

Yet another nail in HD DVD's coffin


The early January announcement by Warner Bros. that the company would no longer be releasing high definition movies in HD DVD, just Blu-Ray, essentially signed HD DVDâ''s death certificate. Now the nails are being placed in the coffin, in spite of Toshibaâ''s mid-January announcement that it would be stepping up its HD DVD marketing campaign.

Todayâ''s nailâ''an announcement that Wal-Mart and Samâ''s Clubâ''s will be dropping all HD DVD players and titles from their shelves. This followâ''s Netflixâ'' Monday announcement that it is phasing out HD-DVD titles. The one million owners of HD DVD players (in North America alone) soon wonâ''t be able to get anything new to watch.

Joining the ranks of the folks about to be â''betamaxedâ'' is tempting, however. HD DVD prices canâ''t be beat, you can easily find a player for just over $100, while Blu-Ray players cost $350 and up.

But donâ''t do it unless you collect orphaned formats. Instead, sit tight and play the prediction game. Hubdub is taking votes on the question, â''Will the HD DVD standard officially be canceled by October 2008.â'' Iâ''m betting yes. You can vote here.

Technology Thinkers Identify Grand Challenges for Engineering


If you're considering a career in science and engineering and are looking for promising research challenges to tackle -- challenges that could lead to Nobel Prize-worthy discoveries, we could say -- you should take a look at the list below.

The list of 14 tech challenges -- with accompanying explanations, essays, videos, and discussion forums -- is part of the study Grand Challenges for Engineering in the 21st Century, prepared by the U.S. National Academy of Engineering (NAE) and released today at the AAAS meeting in Boston.

The challenges:

* Make solar energy economical

* Provide energy from fusion

* Develop carbon sequestration methods

* Manage the nitrogen cycle

* Provide access to clean water

* Restore and improve urban infrastructure

* Advance health informatics

* Engineer better medicines

* Reverse-engineer the brain

* Prevent nuclear terror

* Secure cyberspace

* Enhance virtual reality

* Advance personalized learning

* Engineer the tools of scientific discovery

To identify the challenges, NAE convened an international group of leading technological thinkers that includes William Perry (Stanford professor and former U.S. Secretary of Defense), Danny Hillis (co-founder of Applied Minds), Dean Kamen (inventor and founder of DEKA Research), Robert Langer (MIT bioengineer), Larry Page (Google co-founder), Craig Venter (geneticist), Raymond Kurzweil (inventor and AI author), and Mario Molina (Nobel laureate and UCSD professor).


The group, established in 2006, developed the list of challenges with input received through its website from prominent engineers and scientists and the general public. The choices fall into four themes: sustainability, health, reducing vulnerability, and joy of living.

"We chose engineering challenges that we feel can, through creativity and commitment, be realistically met, most of them early in this century," William Perry, the committee chair, said in a press release. "Some can be, and should be, achieved as soon as possible."

The NAE group decided not to rank the challenges but rather ask the public to do that. You can vote on which one you think is the most important at the project web site:

Climate: The difference between scientific bodies

Sometimes, virtually the same group of scientists can say slightly different things, when they feel less politically constrained. Or at least they can say them more concisely. Thatâ''s the case with the American Geophysical Union and the Intergovernmental Panel on Climate Change. Our space correspondent Barry E. DiGregorio reported this on 25 January.

The American Geophysical Union (AGU), the worldâ''s largest scientific society of Earth and space scientists made the official statement that: â''The Earthâ''s climate is now out of balance and is warmingâ'' and is best explained by â''the increased atmospheric abundances of greenhouse gases and aerosols generated by human activity during the 20th centuryâ''. Unlike the report made in 2007 by the Intergovernmental Panel on Climate Change (a scientific intergovernmental body set up by the World Meteorological Organization (WMO) and by the United Nations Environment Program) the new AGU statement calls for the world community to take individual action [] in an effort to stave off the human impact on global climate change.

Special guest speaker at the meeting, Michael J. Prather, Professor of Earth System Science at the University of California, Irvine, California who was also a lead author of several chapters of the 2007 Intergovernmental Panel on Climate Change said, â''The IPCC has a different role to play than the AGU. The IPCC adjudicates the science, reviews it, and ascertain the pros and cons, and then state what they think is happening or what the uncertainties are but are responding to the request of the international government (UN). The encapsulated summary/statement made by the AGU is made by group of scientists saying here is what is happening, listing the dangers, and then suggests that we should all be doing something, The IPCC report didnâ''t do thatâ''.

â''If you dig at the individual details of the AGU statement I donâ''t think there is anything new there in terms of scientific content, although there is a bit of an update. What is new is pulling it all together in one page,â'' says Prather. â''As an example we took the IPCCâ''s workshop summary and wrote it in the first paragraph of the statement. We are trying to get a message across to what really are the big issues and it shows that global warming is no longer disputed by most scientists.â'' The second paragraph of the AGU statement describes what the dangers are we and what is necessary to avoid them. The third paragraph is a call for action and says combating human impacts on climate change is a diversified and shared responsibility amongst both AGU members and others members of society. â''We are actually calling on individuals to use their ability and their own perception and make their choice so everyone can contribute in their own way to the best of their ability, Prather explained.

For the AGU, which is a very broad body of scientists, Prather and his colleagues who drafted the statement had to convince space scientists, geologists and oceanographers about a call to action on the human influence on climate. â''I think that this was an honest statement of the current facts as we know them and best statement we can make. You are not going to get 100 percent agreement from every AGU member but from the AGU leadership in general, nobody voted against it on the council.â''

The AGU boasts a membership of 50 000 researchers in 137 countries and every four years releases a new public statement reflecting their position on global climate change.

Online AGU statement:

New Environmental Line Item Added to US Nanotechnology Budget

The US National Nanotechnology Initiative has just released its 2009 budget projections, and a new line item, or as its termed in the summary, â''Program Component Areaâ'', that addresses Environment, Health and Safety (EHS) has been added.

Last yearâ''s 2008 budget summary provided only a Program Component Area entitled â''Societal Dimensionsâ''.

But in the breakdown of the new 2009 budget, the EHS program has been retroactively plugged in for 2007 and 2008, representing $48.3 and $58.6 million, respectively for each year. But this year the EHS program has received an increase over 30% from last year to the tune $76.4 million.

These figures compare somewhat favorably to European Commission spending on health issues related to nanoparticles, which amounted to â'¬28 million between 1998 to 2006. Itâ''s not exactly clear how much the EC will dedicate to EHS studies for nanotechnology under the new FP7 Programme, but a rundown of the research projects into nanosafety within Europe can be found here.

The US NNI while being one of the most, if not the most, transparent government nanotechnology funding organizations in the world has come under criticism for its perceived failure to adequately address the nanotechnology hazard question.

Despite this increased funding for EHS research, the criticism will likely not go away as long as there is a vested interested in some NGOs to keep the pressure on to ensure their own necessity to the process as this blog has noted before.

If the NNI really wants to silence the critics, they might allocate some of their budget to hiring these critics as part-time consultants because they have certainly already handled the funding aspect.

Why U.S. Satellite Shoot-down Won't Be Like China's

The Bush administration today ordered the U.S. Navy to prepare for the possibility of shooting a crippled American spy satellite out of the heavens. Reports on the order abound from all the major news agencies, such as the AP, the BBC, CNN, and Reuters. The satellite, widely speculated to be a U.S. NROL-21 reconnaissance vehicle in the press, should fall to earth sometime in the next few weeks.

(Please see our Tech Talk entry from last month Where Will U.S. Spy Satellite Fall? for more on the problems of the damaged spacecraft.)

The decision by the U.S. revolves mainly around the satellite's unused fuel supply of hydrazine, according to American military officials. They fear that the 450 or so kilograms of the fuel onboard could be released into the atmosphere as the satellite descends, possibly spreading the toxic compound over a 200-meter wide area as the vehicle breaks up on impact.

"It is the hydrazine that we are looking at," Marine Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff, told the media at a press conference earlier today at the Pentagon, in Arlington, Va.

The plan announced by the military involves using a single Standard Missile 3 from the Aegis Ballistic Missile Defense System arsenal aboard a U.S. destroyer in the Pacific to hit the approximately 2500-kg satellite as it begins to plummet into the planet's atmosphere and, thereby, burn or dissipate its fuel complement, while also breaking it into pieces more likely to disintegrate on re-entry.

Gen. Cartwright told the media that if the first missile fails, the White House would advise the Navy as to whether it should take a second or third shot from another destroyer. He said that, once the satellite enters the atmosphere, it will be "next to impossible" to strike it with Aegis technology, due to the fluctuations of re-entry. Still, the general said that this approach offered the best chance possible of reducing the potential for harm in this situation. "We are better off taking the attempt than not," he noted.

The controversial nature of such an attempted shoot-down in very low orbit comes by way of comparing today's plan to an incident from last year in which the Chinese military used an anti-satellite (ASAT) system to destroy one of its own aging weather satellites. Thirteen months ago, the incident touched off a roaring debate in the media over the unannounced move as a hostile demonstration of China's newfound capabilities in space. At the time, representatives of the U.S. government denounced the action as being deliberately provocative. Since then, the dispute has largely died down as cooler heads in the public sector prevailed. One of the cooler heads was our own longtime contributor on space technology, James Oberg.

In a blog entry in this space from January 2007, Is China's Satellite Killer a Threat?, Oberg wrote: "The question now is whether China's ASAT missile is a serious weapon or merely a symbol, meant to put pressure on other countries, particularly the United States. To answer it, we must examine the gap separating the satellite-killing demonstration and the needs of a real weapon--one that would be a genuine threat to other countries' satellites."

He reasoned: "The Chinese weapons system has so far demonstrated only that it can pose a threat to low-orbiting objects, of which the most important are reconnaissance satellites. But these satellites have backup." In a masterful analysis, he cautioned policymakers to look beyond the primitive technical merits of the Chinese demonstration and concentrate on its political implications.

(Please visit the James Oberg website for more insight into this topic and related matters involving space warfare technology.)

After the flurry of news today reached one of my bosses at IEEE Spectrum, he sent me a note wondering whether the U.S. plan to kill one of its own satellites wasn't overly similar to last year's demonstration by China, and he pointed to a report in today's New York Times online edition, U.S. Officials Say Broken Satellite Will Be Shot Down, which contained the following language: "The United States has opposed calls for a treaty limiting anti-satellite or other weapons in space. On Thursday, officials pledged that the United States will remain wholly within compliance of treaties requiring the notification of other nations before it launches a missile at the disabled satellite."

So I thought I understood what the implications of the inquiry by this senior Spectrum editor were.

In my reply to him, I noted that I thought the argument put forth in the press conference by Gen. Cartwright was correct, where he said there was no intended parallel between the Chinese action and the U.S plan, because the former was a vehicle orbiting at a much higher altitude, 850 km, than that of the latter, which will be targeted as its decaying orbit descends to about 240 km. The American plan will likely leave some debris intact at the edge of space for a period of time (before it also burns up on re-entry)--if the interception even works. But the Chinese ASAT test left the largest known debris field ever in a prime orbital altitude, where it will pose a constant hazard to future spacecraft.

My conclusion is that the two ASAT scenarios are apples and oranges. The Chinese test was unnecessary and intended. The planned U.S. attempt is necessary and unintended.

Today's Pentagon briefing sounds like the first signal to the rest of the world that the U.S. will respond with its ASAT technology to accidental situations such as this when they threaten populated areas. Beyond that, the plan looks like a response to what Gen. Cartwright said today is "a little bit different" case.

NASA asks public for help in naming new telescope

In an effort to garner publicity for its new space-based gamma-ray telescope, NASA will allow members of the public to suggest a name for it. Currently called GLAST (Gamma-ray Large Area Space Telescope), it is supposed to launch in mid-2008. NASA has realized that the acronym-derived name is not the most compelling.

"We're looking for name suggestions that will capture the excitement of

GLAST's mission and call attention to gamma-ray and high-energy

astronomy. We are looking for something memorable to commemorate this

spectacular new astronomy mission," said Alan Stern, associate

administrator for Science at NASA Headquarters in Washington, via a press release. "We hope someone will come up with a name that is catchy, easy to say and will help make the satellite and its mission a topic of dinner table and classroom discussion."

NASA says the mission's scientific objectives are to:

- Explore the most extreme environments in the universe, where nature

harnesses energies far beyond anything possible on Earth

- Search for signs of new laws of physics and what composes the

mysterious dark matter

- Explain how black holes accelerate immense jets of material to nearly

light speed

- Help crack the mysteries of the stupendously powerful explosions known

as gamma-ray bursts

- Answer long-standing questions about a broad range of phenomena,

including solar flares, pulsars and the origin of cosmic rays

Suggestions for the mission's new name can be an acronym, but it is not

a requirement. Any suggestions for naming the telescope after a

scientist may only include names of deceased scientists whose names are

not already used for other NASA missions. All suggestions will be

considered. The period for accepting names closes on March 31, 2008.

Participants must include a statement of 25 words or less about why

their suggestion would be a strong name for the mission. Multiple

suggestions are encouraged.

To submit a suggestion for the mission name, visit:

Anyone who drops a name into the "Name That Satellite!" suggestion box

on the Web page can choose to receive a "Certificate of Participation" via return e-mail, says NASA. Participants also may choose to receive the NASA press release announcing the new mission name. The announcement is expected approximately 60 days after launch of the telescope.


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