Friday, Sept. 25, 1998
Updated at 8:15 a.m.
The Main Hill Road out of Los Alamos will be closed Saturday and possibly Sunday to repair a broken water line in the vicinity of the Clinton P. Anderson Memorial. Los Alamos County utilities crews will begin work at 6:30 a.m. Saturday and continue until the line is repaired. Signs will be posted. Motorists should plan an alternate route when entering or exiting Los Alamos. |
News from earlier today
Three spacecraft reveal unexplained motion
A team of planetary scientists and physicists has identified a tiny, unexplained sunward acceleration in the motions of the Pioneer 10, Pioneer 11 and Ulysses spacecraft.
The anomalous acceleration -- about 10 billion times smaller than the acceleration we feel from Earth's gravitational pull -- was identified after detailed analyses of radio data from the spacecraft.
The research team, led by John Anderson of NASA's Jet Propulsion Laboratory and including Michael Nieto of the Theoretical (T) Division, considered and ruled out many possible causes for the perturbation in the spacecrafts' motions. The team expects the explanation, when found, will involve conventional physics and understanding, but the team has also considered what implication the anomalous motion has for some new physical effect.
The accelerations are so persistent that they could be pointing to some relevant physics that's been overlooked in trying to explain the motions of bodies in the universe.
The research has been accepted for publication in Physical Review Letters.
"In order of decreasing probability the possible causes are some systematic effect associated with the spacecraft; some subtle effect associated with our tracking systems, which would be important to know for space navigation; or some manifestation of 'new physics,' " Nieto said. "By looking at the third possibility we can examine how well 'normal' physics works, which in itself gives you further insight into the universe."
The researchers analyzed signals sent from Earth that were actively reflected by a transponder on the spacecraft. The resulting Doppler shift in the signal was used to calculate the motions. NASA's Deep Space Network sent and received the signals.
Pioneer 10 was officially tracked until March 1997, when it was some six billion miles away from the sun. (Pioneer 10 is still transmitting, and occasional additional radio Doppler data is provided to the research team.)
Pioneer 11, due to a radio failure, last sent useful radio Doppler transmissions in October 1990, when it was less than three billion miles from the sun. Ulysses has been tracked on its looping flight out of the ecliptic and around the sun's poles.
The researchers also examined Galileo data from that craft's journey from Earth to Jupiter.
Measurements of both Pioneer craft and Ulysses gave approximately the same answer for the strength of the anomalous acceleration. Galileo, too, yielded a similar value, but its flight was so close to the sun the researchers could not rule out the effects of solar radiation pressure.
Newton's laws of gravity alone -- with the sun providing the dominant gravitational force - are good enough for NASA to send spacecraft on planetary rendezvous with near-pinpoint precision. But the anomalous motions of these spacecraft are so small that the researchers had to consider numerous possible causes: perturbations from the gravitational attraction of planets and smaller bodies in the solar system; radiation pressure, the tiny transfer of momentum when photons impact the spacecraft; general relativity; interactions between the solar wind and the spacecraft; possible corruption to the radio Doppler data; wobbles and other changes in Earth's rotation; outgassing or thermal radiation from the spacecraft; and several others.
The researchers have so far not found that any of these effects can account for the size and direction of the anomalous acceleration.
After exhausting the list of possible "normal" explanations, the researchers looked at possible modifications to the attractive force of gravity or the possible influence or non-ordinary matter, or "dark" matter.
The dark matter explanation didn't hold up because so much matter would have been required to create the measured spacecraft acceleration it would have affected motions of other bodies in the solar system.
Looking at other mathematical representations for gravitational interactions also "come up against a hard experimental wall," the researchers wrote: namely that the gravitational effect would also be seen in planetary motions, especially for Earth and Mars.
"If the anomalous radial acceleration acting on spinning spacecraft is gravitational in origin, it is not universal," the researchers concluded. It would have to affect bodies massing a thousand kilograms or so more than bodies the size of planets.
Nieto has long been interested in the possibility that gravity works differently on antimatter than on the familiar matter that makes up our everyday world. This led him to consider how well we understand gravity's influence on normal matter and whether studies of the motions of comets or spacecraft could be used to identify any deviations from the expected influence of gravity.
Meanwhile, Anderson and his JPL colleagues had for years puzzled over "residual errors" between the calculated and measured positions of the Pioneer spacecraft. Anderson first saw the effect in 1980, but until he had accumulated data over the next 15 years, he could easily dismiss it as systematic errors. "Like a lot of problems in astronomy, many years of observation are needed," Anderson said.
After Anderson and Nieto hooked up, the group redoubled its efforts to analyze the spacecraft motions and possible contributing perturbations. An independent analysis of the motions using a computer program developed by The Aerospace Corp. ruled out errors in JPL's orbital determination software as the source of the anomalous acceleration.
The researchers noted that NASA's planned mission to Pluto, which would include more accurate tracking systems, will provide additional, high-quality data for investigating this mystery. In addition, Pioneer 10 is still a potential source of data, since its transmitter is still functioning. The team also is conducting more detailed analyses of Ulysses' swing around the sun.
"Clearly, more analysis, observation, and theoretical work are called for," the researchers concluded.
Other authors on the PRL paper were Philip Laing of The Aerospace Corp., Anthony Liu of Astrodynamic Sciences, and Eunice Lau and Slava Turyshev of JPL.
--John R. Gustafson
Radio station KSWV, 810 AM will do a live broadcast today beginning around 1:30 p.m. near Ashley Pond in downtown Los Alamos as part of the Lab's Hispanic Heritage Month activities. Among those interviewed will be Lab Director John Browne, acting Deputy Director for Business Administration and Outreach Tom Garcia, and acting Diversity Office Director Mick Trujillo. A topic of discussion will be diversity. |
Mike Walkord, left, of Systems Support (BUS-7) talks with Eve Stockton of the U.S. Social Security Administration at one of the Financial Fair vendor information booths Thursday on the second floor of the J. Robert Oppenheimer Study Center. Compensation and Benefits sponsors the fair, which continues today. For more information, see Tuesday's Daily Newsbulletin or go to http://www.hr.lanl.gov/html/benefits/financial_fair.html online. Photo by Liz Padilla |
Speaker says mills were the lifeblood for many
If you owned a "molina," or a mill, in the 1600s through 1800s in New Mexico, you were probably rich, according to Earl Porter of El Rancho de las Golondrinas.
Not rich in money, Porter explained, but in grain and other items that villagers would give to mill operators in exchange for having their grain milled for flour. Mills were the lifeblood for many families and small villages in Northern New Mexico, he said.
Porter spoke about mills Wednesday in the Laboratory's Physics Building Auditorium as part of the Lab's observance of Hispanic Heritage Month. "400 Years of Technology in New Mexico: A Cuarto Centenario Commemorative," is the theme for the Laboratory's celebration of national Hispanic Heritage Month, Sept. 15 through Oct. 15.
Hispanic Heritage Month activities continue from noon to 7 p.m. today with a community "tent event" at Ashley Pond downtown.
The Hispanic Diversity Working Group is sponsoring Hispanic Heritage Month activities at the Laboratory. The Diversity (DV) Office is providing funds to pay for expenses associated with the Hispanic Heritage Month activities.
Porter is an engineer by profession, but he became interested in mills after visiting El Rancho de las Golondrinas in La Cienega during the ranch's harvest festival in 1989. "I fell in love with it within 15 minutes of being there," he said of the old mill at the ranch that Porter has restored.
Since then, he's traveled around the country researching old mills, photographing them and is in the process of writing a book. Porter said he's fascinated with mills; his wife thinks he is "obsessed" with them, said Porter.
"I've always been interested in what I call primitive technology," Porter said, describing how the now centuries-old mills were constructed out of trees, rock and mud. This technology, brought to New Mexico by Spanish settlers, may have been primitive, but it was effective. "I've become extremely fascinated with the cleverness of the engineering the Spanish brought with them to New Mexico," said Porter. "The underlying engineering behind old wooden mills was a marvel . . . The mills were technologically very sophisticated, but very simple."
Porter read excerpts of an English translation of a report about a letter by one of Don Juan de Oñate's brothers in March 1601, some three years after Oñate first came to New Mexico. The letter said Oñate's contingent had erected a flour mill that had produced 7,000 bushels of flour in the short time they had settled in Northern New Mexico.
"If you want to eat flour you must have a mill," said Porter. "I maintain that the Spaniards built a mill before they built a church."
Porter called the mills the most significant technology the Spaniards brought to New Mexico other than the firearm.
Porter said he volunteered to work on the mill at El Rancho de las Golondrinas rather than wear a uniform of a Spanish soldier. Being an engineer, "I was a little concerned about the accuracy of their interpretation of the technology," said Porter.
He spent the next two years -- and about 3,000 hours -- researching old Spanish mills before he began restoring an old Spanish mill at the living ranch.
When Porter began his research, he estimated there were between 15 and 20 mills in New Mexico. His research soon uncovered about 450 mills.
Today, there are less than a dozen intact mills in New Mexico, three of them at El Rancho de las Golondrinas.
Early Northern New Mexico families were primarily farmers and sheepherders, said Porter. There was no cash economy to speak of, and it was difficult for mill operators to move milled grain to market because of poor roads. So early milling was called "toll milling," he said.
Mill operators would mill other farmers' grain, keeping a certain percentage of it as a form of payment, he explained. Because mill operators had ample supplies of grain to mill, they could better feed their families, said Porter.
He said that an "inventory," a type of census, conducted around 1850 of the New Mexico territory indicated that mill operators had larger families and the mortality rate in those families was lower than in families of non-mill operators.
The old Spanish mills, Porter said, were built with basalt rock. Grain was trapped between two mill stones and ground until it became very fine, and eventually flour. The mill had a horizontal wheel with slats in it. Water spun the wheel like a turbine to power the mill.
"It is one of the most clever designs you'll ever see . . .it is extremely sophisticated even though it's a pile of rocks and mud and wood," he said.
Other mills had stones that rotated, or swung like a pendulum to grind flour.
The decline of mills was accelerated, Porter said, after World War II when people decided to purchase bread from stores, rather than from mills. But in Rincon, a small community near Hatch in southern New Mexico, there is a mill that mills 175,000 pounds a day of wheat for flour. Much of it is shipped to the west coast for tortillas, he said.
More information about Hispanic Heritage Month can be found at http://www.lanl.gov/projects/DIVERSITY/hdwg/hhmonth.html or see the Sept. 23 Daily Newsbulletin.
--Steve Sandoval
Energy secretary/Russian minister sign agreement
Energy Secretary Bill Richardson and Russian Minister of Atomic
Energy Yevgeny Adamov Tuesday signed an agreement to bring commercial enterprises
to Russia's closed "nuclear cities" and a joint report that outlines
a framework to resolve the problems with the agreement for U.S. purchases
of uranium from Russian nuclear weapons. The negotiations and signing ceremony
took place during a meeting of the International Atomic Energy Agency General
Conference in Vienna, Austria. (http://www.iaea.org/GC/gc42/gc_pr/doenews1.html)
Also at the IAEA meeting, Richardson, Adamov and Director General of the International Atomic Energy Agency Mohamed ElBaradei reviewed progress made under the Trilateral Initiative inaugurated by their predecessors two years ago (http://www.iaea.org/GC/gc42/gc_pr/gcpr9818.html). The Trilateral Inititiative is a collaborative effort between the IAEA, Russia and the United States to to investigate technical, legal and financial issues associated with IAEA verification of weapon-origin fissile material designated as no longer required for defense purposes.
The Laboratory is leading the technical support to the U.S. government for the Trilateral Initiative. During the past two years, the Laboratory has coordinated the DOE effort to investigate technical means by which the IAEA can verify and monitor fissile materials while protecting sensitive nuclear weapons information.
Jim Tape of the Threat Reduction (TR) Directorate leads the Lab effort.
Sam Gibson, left, human resources manager for the University of California Laboratory Administration Office, talks with visitors at the joint Laboratory/UC information booth at last weekend's Los Alamos Chamberfest downtown. Chamberfest is sponsored by the Los Alamos County Chamber of Commerce. Information about UC and Lab programs and projects was available at the booth, and drawings were held for T-shirts, science education-related items for children and several copies of the UC book, "In Pursuit of Ideas." The information booth is part of the Lab's and university's community outreach efforts. Photo by Mike Kolb, Community Relations (CRO) Office |
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