Saturday, August 2, 2008
On Friday, August 1, sky-watchers will have an excellent day, as they will get the chance to observe a total eclipse of the sun. It will be perfectly visible to those located in Greenland, Siberia, Mongolia and China.
Astrophysicist Fred Espenak, an eclipse expert based at the NASA Goddard Space Flight Center, said the sun would be completely covered for just a bit under two and a half minutes.
He added that your typical eclipse has a duration of three minutes and the longest possible one can last for seven and a half minutes.
Fred Espenak added that roughly one in four eclipses is a total eclipse and that there are about seven such events during any given decade. However, in any randomly picked location on Earth, a total eclipse would be observable only once in 375 years.
Obviously enough, this is a chance that should be well appreciated; in the case of a total eclipse, 50 percent of the daytime world can’t see it at all and 49 percent can see it partially. That remaining one percent experiences a sight that Fred Espenak calls "drop dead gorgeous."
He goes even further with his enthusiasm, saying that on a scale of one to ten, a total eclipse ranks at ten million and that everyone should include seeing such an astronomical event on their life list.
The biggest problem sky-watchers may have is, obviously enough, related to the weather. If the skies are grey, there is absolutely nothing to do.
All the people with the slightest interest in astronomy or nature in the aforementioned countries are probably keeping their fingers crossed right now.
Thousands of eclipse chasers have gathered in Siberia on Friday to experience day turn to night when the moon's shadow covered over the sun for a 140-second chill.
The polar city of Nadym was the first to experience the eclipse, at its peak length of 2 minutes and 27 seconds of darkness.
But most eclipse pilgrims gathered in Russia's third largest city of Novosibirsk, which lies directly in the arc of the eclipse.
Experts estimated that the eclipse is a once-in-300-years event in Novosibirsk, where the solar blackout is set to last 2 minutes and 20 seconds, but the phenomenon occurs worldwide about every 18 months.
A partial eclipse will be visible in Moscow, about 2,000 kilometres east of Siberia's hub city, where a maximum of 58 per cent of the sun will be obscured at 1408 Moscow time.
The Arctic archipelago of Svalbard, off northern Norway was one of the places that offered astronomers and others a chance to experience an almost total solar eclipse Friday.
The main settlement Longyearbyen offered a 93 per cent eclipse compared to some 80 per cent in northern Norway and 50 per cent in the Norwegian capital Oslo, the Norwegian Space Centre said.
Some 1,000 people gathered in Oslo's Frogner Park to experience the event, news agency NTB said.
Another solar eclipse won't be seen in Russia until 2030, while the next total eclipse will be over North America in 2017.
A solar eclipse will be visible in Shanghai and other parts of China next year.
An eclipse of the sun occurs when the moon passes directly between Earth and the sun. When the moon’s shadow falls on Earth, people within that shadow see the moon block a portion of the sun’s light.
The moon’s shadow has two parts, an umbra and a penumbra. The umbra is the “inner” part of the moon’s shadow. The penumbra is the moon’s faint “outer” shadow.
During a total solar eclipse, like the one that takes place August 1, the moon appears to cover all of the sun for observers located in the moon’s umbral shadow, also known as the “path of totality.” Those viewing the eclipse from the moon’s penumbral shadow see the moon cover a portion of the sun.
What a view!
This jet, surmounted more than 75-percent of the atmosphere (in terms of mass) and almost all of its water vapor below, providing an opportunity to see what happens in the Earth's upper atmosphere when the sun is switched off, so to speak. Minutes before totality, the light inside the cabin faded, much in the same manner as lights in a theater dim before the start of a show.
As the last of the sun's rays slipped behind the jagged lunar edge it produced a beautiful and long-lasting "Diamond Ring" effect.
The dark lunar shadow then swept in from the west and enveloped the plane in an eerie darkness. The sun's beautiful corona heralded the beginning of the total phase. It appeared to throw off several long streamers – typical for a corona at sunspot minimum, which is where solar activity is now.
Adding to this scene was an array of four bright planets arranged to the lower left of the darkened sun: Mercury, Venus, Saturn and Mars. Some observers searched near the sun for a small, faint comet that was discovered on SOHO satellite imagery some hours before the eclipse. But no evidence of the comet was observed.
Posted by SANJIDA AFROJ at 6:14 PM
researchers have identified the brain mechanism that switches off traumatic feelings associated with bad memories, a finding that could lead to the development of drugs to treat panic disorders.
Scientists from UCI and the University of Muenster in Germany found that a small brain protein called neuropeptide S is involved in erasing traumatic responses to adverse memories by working on a tiny group of neurons inside the amygdala where those memories are stored.
"The exciting part of this study is that we have discovered a completely new process that regulates the adverse responses to bad memories," said Rainer Reinscheid, pharmacology and pharmaceutical sciences associate professor at UCI. "These findings can help the development of new drugs to treat conditions in which people are haunted by persistent fears, such as posttraumatic stress disorder or other panic disorders." The study appears in the July 31 issue of Neuron.
In tests, scientists exposed mice to situations that caused adverse memories. The scientists saw that when NPS receptors in amygdala neurons are blocked, the traumatic responses to bad memories persisted longer. In turn, when scientists treated the mice with compounds activating these receptors, traumatic responses disappeared faster.
After a traumatic experience, environmental cues often become associated with the bad experience and re-exposure to the same environment can trigger fearful emotions or even panic attacks, according to Reinscheid.
Other research has shown that forgetting such negative experiences may require "new learning," such as re-exposure to the place where the original experience occurred but this time without any harmful consequences. Reinscheid said this process, called the extinction of memories, occurs in both humans and laboratory animals such as mice. Until this study, scientists did not know about the specific neurons and molecules involved with extinction learning of fear memories in the brain.
Previous work by Reinscheid's group has shown that NPS is involved in regulating wakefulness and anxiety. Last year, they found evidence that a particular genetic variant of the NPS receptor may increase vulnerability to panic disorder.
Stewart D. Clark, Naoe Okamura, Dee M. Duangdao, Yan-Ling Xu of UC Irvine, and Kay Juengling, Thomas Seidenbecher, Ludmila Sosulina, Joerg Lesting, Susan Sangha and Hans-Christian Pape of the University of Muenster also worked on this study, which was funded in part by the National Institute of Mental Health.
Apple has issued a major security patch for Mac OS X, as well as Mac OS X Server to fix the recently revealed DNS flaw.
The DNS flaw was discovered by security researcher Dan Kaminsky, and was made public by accident on July 21.
Since that point, many companies have been working as quickly as possible to try and get a patch out for the DNS flaw.
All unpatched systems are said to be very vulnerable to the attacks, which allow people to take traffic from a domain name, and redirect it to a malicious site.
Apple has been under fire as of late, as many have been stating that they have been taking too long to get this patch out.
Thankfully for Apple users though, the patch is now out and there is no longer anything to worry about