In This Issue...
On Wednesday evening, February 20, most of North American will be treated to a total lunar eclipse. NASA's Web site contains a number of useful and interesting pages related to this eclipse and others. Visit the above Web site, as well as http://sunearth.gsfc.nasa.gov/eclipse/LEmono/TLE2008Feb21/image/TLE2008Feb21-PST.GIF The latter page contains a diagram of the progression of the eclipse for those living in the Pacific Standard Time Zone. A Web page entitled "Lunar Eclipses for Beginners" is available at http://www.mreclipse.com/Special/LEprimer.html
[from the above Web site] During totality, the spring constellations are well placed for viewing, so a number of bright stars can be used for magnitude comparisons. Regulus (mv = +1.40) is 3° northwest of the eclipsed Moon, while Procyon (mv = -0.05) is 40° to the west, Spica (mv = +0.98) is 51° to the southeast, and Arcturus (mv = -0.05) is 58° to the northeast. Alphard or Alpha Hya (mv = +1.99) is 23° to the southwest and Saturn (mv = +0.2) is just 3° to the northeast of the Moon. [Note: Saturn will shine brightly during the eclipse.]
The entire event is visible from South America and most of North America. Observers along North America's west coast miss the early stages of the partial eclipse because it begins before moon rise. Alaskans in Anchorage and Fairbanks experience moonrise during totality but bright evening twilight will make it difficult for sourdoughs to view the event. Western Europe and northwest Africa also see the entire eclipse. Further to the east (east Africa and central Asia), the Moon sets before the eclipse ends. None of the eclipse is visible from eastern Asia or Australia...
(2) "See the Falling Spy Satellite" by Joe Rao
Source: SPACE.com - 15 February 2008
During this week, a wayward U.S. spy satellite will make passes across North America and western Europe soon after sunset and should be easily visible to the unaided eye.
That's if it doesn't get shot down first [see below article].
The falling satellite is named USA 193. It was launched Dec. 14, 2006. It has been described as being similar in size to a school bus and might weigh as much as 10,000 pounds. It carries a sophisticated and secret imaging sensor but the satellite's central computer failed shortly after launch, never reaching its final orbit, and the Pentagon declared it a total loss in early 2007.
Since then, the satellite's orbit has been decaying--slowly at first. But in recent weeks USA 193's nearly circular orbit has been rapidly lowering. Currently, its altitude is approximately 160 miles (260 km) above the Earth.
Unless a proposed plan by the Pentagon is enacted to shoot down USA 193 during the next week, the satellite could conceivably re-enter the Earth's atmosphere and burn up sometime in mid-March.
Through this Friday, Feb. 22, USA 193 will make a number of evening passes over North America and Western Europe. Its orbit is inclined 58.5-degrees to the equator, a setup that makes it readily observable from most of the Northern Hemisphere.
During this period, USA 193 will move along a general southwest-to-northeast trajectory and pass over a number of cities in the United States, southern Canada and western Europe.
Predictions for the times and locations of USA 193 are available at the Heavens Above website (www.heavens-above.com). Based on this website's sighting information, USA 193 will be very favorably placed for observation over a number of large cities, assuming it is still in orbit around the Earth and weather conditions permit.
What to look for
To find satellites, it's also helpful to know how to roughly measure the sky. Your clenched fist held at arm's length measures roughly 10-degrees of the sky. (From the horizon to the top of the sky (the zenith) measures 90-degrees.)
From Boston and Seattle, nearly overhead passes are forecast for (respectively) Feb. 18 and Feb. 22. And on the latter date, London, England should have a fine pass, with USA 193 arcing as high as 77-degrees above the horizon.
It should be stressed that because of the rapidly changing nature of its orbit, sighting information from Heavens-Above should be checked frequently.
Those who have seen the International Space Station (ISS) flying across their local skies should be aware that USA 193 will appear noticeably fainter, since it's quite a bit smaller than the ISS. Yet, at its brightest, the spy satellite still should rank as bright as the brightest stars, at roughly first magnitude in astronomers parlance.
Also, since the spy satellite is in a lower orbit than the ISS, expect USA 193 to move much more rapidly across your line of sight.
Source: Space.com - 14 February 2008
President George W. Bush approved a Defense Department plan to try and shoot down a crippled spy satellite after becoming convinced that the spacecraft's toxic hydrazine fuel posed an unacceptable risk to people on the ground, senior U.S. government officials said at a Pentagon press briefing Feb. 14...
U.S. government officials recently acknowledged its orbit is decaying and that it would re-enter the atmosphere sometime in March. In order to prevent the satellite's hydrazine fuel tank from coming down intact and possibly dispersing highly toxic fumes over an area roughly the size of two football fields, U.S. officials will take the extraordinary step of attempting to shoot it down just before it re-enters. A direct hit to the spherical tank, which measures about 40 inches (100 centimeters) across, would result in the hydrazine being dispersed in the atmosphere and posing no hazard on the ground, the officials said.
The intercept attempt, which will involve a Standard Missile 3 fired from a U.S. Navy Aegis ship, will take place during a window that opens after NASA's space shuttle Atlantis returns from its International Space Station-construction mission Feb. 20 and will remain open for several days. The window was selected based on the satellite's current re-entry trajectory and the U.S. government's desire to minimize hazards in space, in the air and on the ground.
U.S. Marine Corps Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff, said the intercept, if successful, will take place at a low enough altitude to minimize orbital debris. Cartwright, along with NASA Administrator Mike Griffin said well over 50 percent of the debris from a successful intercept will re-enter and burn up in the atmosphere within two orbits, or 10-15 hours, while the remainder would come down within a matter of weeks. Satellites typically operate at altitudes higher than the debris is expected to reach. The international space station orbits Earth at an altitude of around 199 miles (320 kilometers).
Griffin said the intercept is expected to occur at an altitude of about 149 miles (240 kilometers). He noted that the controversial anti-satellite test conducted by China last January occurred at an altitude of some 528 miles (850 kilometers) and much of the resulting debris will remain in orbit for 20 or more years.
Ambassador James Jeffrey, President Bush's deputy national security advisor, said another difference is that the United States is informing the international community well in advance of the attempted shoot-down. He emphasized that the motivation behind the test is to protect lives on the ground and that the action does not violate any U.S. treaty obligations.
Cartwright said he was confident in the intercept's chances of success. The Standard Missile 3 and Aegis system, developed for the sea-based component of the U.S. missile defense architecture, are both well understood. He said the software on the missile and the ship-based Aegis targeting system will have to be modified for the attempt...
The intercept's location will be chosen to maximize the chance that any debris that survives the kinetic impact of the missile and re-entry will land in the ocean, Cartwright said. The satellite and missile will close on one another at a velocity of about 22,783 miles (36,667 kilometers) per hour. Even if the kinetic interceptor only grazes the satellite it is likely to force it to re-enter the atmosphere sooner than otherwise would have been the case.
The operation will involve three ships and two backup missiles, Cartwright said. He outlined two possible scenarios in which the backup missiles would be used, one involving a failure of the primary interceptor to launch. If the first missile launches but misses the satellite, a second shot might be attempted depending on the likelihood that it can be pulled off in a location that likely would result in the debris falling harmlessly at sea.
After the first shot is attempted, the Pentagon will use its network of ground and space-based sensors to assess whether it scored a hit. In the case of a miss, a second shot, if attempted, could take place some two days after the first.
The satellite, a test craft owned by the secretive U.S. National Reconnaissance Office, weighs about 5,015 pounds (2,275 kilograms), Cartwright said. U.S. officials estimate that about half of the hardware would survive the fiery re-entry and plunge to Earth, he said.
Cartwright insisted there was no concern that the satellite's sensitive, classified technology would survive re-entry and fall into the wrong hands, and said the decision to attempt the shoot-down was driven strictly by safety considerations. "This is all about trying to reduce the danger to human beings," he said.
Cartwright said satellites of this size--he said it is about the size of a bus--have re-entered throughout the space age, but few have done so with a full load of hydrazine.
The hydrazine tank aboard the failed satellite is about the same size as the one that was aboard the doomed space shuttle Columbia. The tank landed intact in an unpopulated wooded area in Texas after the orbiter broke up on re-entry in 2003.
Griffin said analyses have concluded that it is all but certain that the hydrazine tank aboard the crippled satellite will land intact if no action is taken. The tank will be breached and full of slushy hydrazine, which will evaporate and dissipate over the immediate area, he said. If this occurs in a populated area it could result in injury or even death, officials said...
Source: Discover Magazine - February
Pathologist Thomas Harvey held on to Albert Einstein's most prized possession--his brain--for 43 years. After the physicist's death on April 18, 1955, Harvey performed an autopsy and kept the brain... In the following years he took it with him in his travels, even at one point putting it in Tupperware for a cross-country drive in a rented Buick Skylark to visit Einstein's granddaughter, Evelyn. By car and mail Harvey parceled out more than a thousand slices of the brain, mostly in the name of research. Three resulting studies (published in The Lancet, Experimental Neurology, and Neuroscience Letters) and three books have tried to answer the question: What do smarts look like? No one can say for sure, but researchers did find a few surprises about one of the most famous brains of all time.
[A photograph of Einstein's brain is located at the above Web site, along with labels identifying certain brain regions that were of particular interest. Some of the findings follow below.]
Frontal Lobes: A study of one slice from Einstein's right frontal lobe, published in 1996 by a neurologist from the University of Alabama at Birmingham to whom Harvey had mailed chunks of the brain in alcohol-filled Ziplock bags, found that Einstein's cerebral cortex was thinner than that of the control subjects. The researcher suggests that Einstein's brain had a greater density of neurons and decreased interneuronal conduction time, which may have translated into faster thought processing. The study's limited results drew little attention.
Parietal Operculum: The most distinctive brain feature was found in samples that Harvey transported across the Canadian border in 1996 and delivered to neuroscientist Sandra Witelson at the Michael G. DeGroote School of Medicine at McMaster University in Ontario. Within each parietal lobe, Einstein appeared to be missing the parietal operculum--possibly leading to more interconnections in the inferior parietal region.
Inferior Parietal Region: In Einstein's parietal lobes--the area related to visual imagery and mathematical thinking--each hemisphere was one centimeter, or 15 percent, wider than that of a control group, according to Witelson. Within the lobe she found a "large expanse of highly integrated cortex" in the inferior parietal region. Witelson points to Einstein's unique brain anatomy as a possible reason for his exceptional ability. Her findings, published in 1999, were widely noted.
Weight: Einstein's brain and found that it tipped the scales at a mere 2.7 pounds. This was slightly less than the 3.1-pound average adult male brain in Witelson's study of 35 control-group brains, clearly indicating (in men, at least) "that a large brain is not a necessary condition for exceptional intellect," Witelson says.
Neurons and Glial Cells: In 1984 neuroscientist Marian Diamond at the University of California at Berkeley studied slices of brain tissue Harvey had mailed to her, calculating the ratio of neurons to glial cells, the cells that support and nourish neurons. In one area associated with math and language skills on the left side of Einstein's brain, she counted 73 percent more glial cells per neuron than average. This abundance, she speculates, might "reflect the enhanced use of this tissue in the expression of his unusual conceptual powers." Even so, her study was criticized as flawed.
"Children of a Lesser God" by Michele Zackheim
This article provides information and insights about Einstein's progeny, concluding with this quotation from one of his great-grandchildren: "We Einsteins do not believe in authority. We solve problems in highly unconventional ways,...in our own way.”
Source: "Science News Online" - 9 February
A 3-month-old baby can't help you with your taxes, but nonetheless possesses a brain-based grasp of numbers, a new study indicates.
Previous studies suggested that, by 4-1/2 months, infants detect changes in the number of items in a set. Some researchers regard this feat as evidence for an early number sense. Others attribute it to babies' tendency to notice novel events or to other nonnumerical cues. The new study is the first to connect infant number sense with brain activity.
By 3 months of age, infants already display distinct neural pathways for distinguishing the number of objects that they see as well as for identifying objects, say neuroscientist Véronique Izard of Harvard University and her colleagues. These pathways correspond to a pair of neural networks also found in adults.
A "where-and-how" network primarily monitors an object's location, size, and potential uses, while a "what" network handles its identification.
"Our findings show that infants as young as 3 months are able to process numbers and to identify objects thanks to specific neural systems," Izard says. Her team presents its findings in the February PLoS Biology ("Distinct Cerebral Pathways for Object Identity and Number in Human Infants" by Izard, Dehaene-Lambertz, and Dehaene).
Izard's group studied 36 infants, all 3 months old. Each youngster wore a cap with sensors that recorded electrical activity from the brain's surface.
While being held by a parent, babies watched a series of images on a computer screen. Most screens depicted the same object, such as a cartoon character, shown in arrays of the same number. Occasionally, an image showed either a new object or a different number of previously seen objects.
The infants' brain surfaces displayed distinctive electrical responses within a fraction of a second after number and object changes.
The researchers then used a computer model to estimate neural sources of the infants' electrical responses.
As has been reported for adults and children, brain areas along the top of the left temporal lobe responded vigorously in the infants' brains as they observed object changes, accessing the "what" network.
Number changes elicit responses primarily from the "what-and-how" network, which functions in the lower part of the brain. But in the infants, this activity was focused in right-brain areas. Other studies indicate that left-brain contributors to this network appear during childhood and strengthen by adulthood.
The new study also counters thinking that infant awareness of changes in objects and numbers merely reflects a tendency for novel events to grab a baby's attention, Izard maintains, because the networks triggered in the study lie largely outside of brain regions involved in attention.
Intriguingly, infants showed comparable neural responses to changes in both small (four or fewer) and large numbers of items. Psychologists have theorized that small-number detection relies on a system for tracking a few individual objects, whereas large-number detection depends on a system for estimating the magnitude of a group of items.
"These are interesting findings," comments psychologist Susan C. Levine of the University of Chicago. A common neural pathway for small and large numbers in infants suggests that the magnitude-estimation system operates for all numbers, although a separate small-number system must also exist, Levine proposes.
Recent and related articles:
(a) "The Evolutionary and Developmental Foundations of
Mathematics" by Michael J. Beran
(b) "Semantic Associations between Signs
and Numerical Categories in the Prefrontal Cortex" by Ilka
Diester and Andreas Nieder
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