Starfall for the weekend: Perseids

Image NASA Marshall Space Flight Center Meteor Showers
at Flirck

Perseids. Each year there is a meteor shower, or as they say rain of stars, this year it is for Perseids, one of the most popular meteor showers that come this weekend. Amateur astronomer Fred Bruenjes organized this composite image of the Perseids in 2007 of nearly 3,000 images taken during two nights. The picture illustrates that the Perseids come from the same area. You may not be deployed most spectacular of the year, most years, that honor goes to the Geminids in December. However, the shower is almost certainly the most watched meteor shower, coming as they do in the hot months of summer vacation.

Advised to look to the sky in a place as dark as possible and without obstacles to sight in the early hours of the nights of Saturday and Sunday. The Perseids Tears of St. Lawrence are produced when the Earth, in its way, through the tail of comet Swift-Tuttle. The Perseids are bits of periodic comet Swift-Tuttle.

 As the Earth passes near the comet's orbit, small pieces of debris, mostly the size of grains of sand, but some as large as peas or larger - enter the atmosphere at 60 km per second (134.000 mph .) From an altitude of about 100 km (60 miles), a meteoroid compresses the air in front of him like water before a speedboat, creating a shock wave hot. This is what most people see - not a little of the remains themselves. 

Meteors come from comets are more like clumps of dust that rocks. Even the larger ones are too fragile to reach the ground as meteorites - unlike the pieces of rock and iron, which come from asteroids. Earth passed closer to the comet Swift-Tuttle in 1992 and put on displays Perseid particularly spectacular in the years around then. The rain has returned to normal. The comet will not approach as close again until around 2125, but that does not mean that the Perseids this year will not be worth finding your own piece of dark sky. Try to get as far away from city lights as possible, bring a reclining chair to lie back and be patient.

 There is an application Meteor Counter if you want to capture some images, and then make a recording of critical data for each meteor: time, magnitude, latitude and longitude, along with the option of verbal annotations. Then these data are loaded automatically NASA researchers for analysis. Meteor Counter - (apple store) also offers a news and calendar of events, which are updated by professional scientists to keep you informed of the latest developments and meteor showers the next.

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Greenland thaw unprecedented NASA reports

NASA has announced that its satellites have detected an unprecedented thaw of Greenland, as the melted area is one of the largest detected in 30 years of control in satellite observations. Recently detected a large iceberg was clear from the area called Petermann. This time with this report explains that most of the ice cover of Greenland, from his thin, low coastlines to its 2 kilometers thick center, experienced some degree of fusion on its surface, according to the three independent satellite measurements analyzed by scientists from NASA and the university. On average in the summer, about half of the surface of the Greenland ice sheet melts naturally.

 "The Greenland ice sheet is a large area with a varied history of change. This event, along with other natural phenomena, although rare, as the case of large delivery last week in the Petermann glacier, are part of a story complex, "said Tom Wagner, director of the Washington NASA cryosphere program.

 According to satellite data, it is estimated that 97 percent of the surface of the ice thawed at some point in mid-July. Investigators have not determined whether this event extensive merger affect the overall volume of ice loss this summer and contribute to rising sea level. What we explain is that the higher parts of the ice tend to thaw, but equally freeze back in place, what is called FUSION, so near the coast, some water is retained by fusion the ice and the rest is lost in the ocean. But this year, as detected, the degree of melting ice in or near the surface greatly increased. 


Son Nghiem of the Jet Propulsion Laboratory in Pasadena, California, says that was the analysis of radar data from the Indian Space Research Organisation (ISRO) Oceansat-2 Satellite who last week made him realize that most of Greenland appears to have undergone fusion on its surface on 12 July. 


Nghiem said: "This was so extraordinary that at first I questioned the result: Is it real or due to an error of data?" . Then given the task to corroborate these results and consult with Dorothy Hall at Goddard Space Flight Center in Greenbelt, Maryland City of studying the surface temperature of Greenland with the Moderate Resolution Imaging Spectrometer (MODIS) on board NASA's Terra and Aqua satellites and confirmed by MODIS that temperatures were unusually high and that the melting was extensive on the surface of the ice. 


The melting quickly spread. The melting was shown on maps derived from three satellites and showed that the July 8, about 40 percent of the surface of the ice had melted. July 12, 97 percent had melted. This event coincided with the extreme fusion of unusually strong ridge of hot air, or a dome of heat over Greenland. 

This merger marked the Summit and the ice has not happened since 1889, according to ice cores analyzed by Kaitlin Keegan at Dartmouth College in Hanover, NH National Oceanic and Atmospheric Administration weather station Summit air at temperatures above or confirmed floated within one degree of freezing for several hours 11-12 July. Ice cores  can have fusion events every 150 years on average. Indicate that it may be of concern if such events were still observed in FUSION type the coming years, as it can alter sea level globally and some villages near the coast disappear.

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Dies at 61 the first U.S. woman astronaut: Sally Ride

At 61 years of age die Sally Ride the first American astronaut. Who in 1983 was the first U.S. woman to be in orbit as part of the STS-7, a victim of cancer. The mission was in the Space Shuttle Challenger.  It seems a little ironic to remember the pioneer of aviation in Google with a doodle, because in some countries by the time difference as marked on 24 July when the other side of the world are reminded of the first American woman astronaut also that was in orbit but due to his death. Sally Ride into space traveling at 32 years old, and announced his death after battling pancreatic cancer. He died in La Jolla, California. 

Her participation as an astronaut aboard the Challenger and the launch was held on June 18, 1983. But this was not its only flight, Sally made ​​a second space flight on the Challanger just one year later in 1984 and participated in the commission that investigated the accident of the same in 1986, the Rogers commission. Sally stopped working for NASA to become a researcher and teacher in physics from Stanford University and was also involved in a program for kids interested in science. 

NASA through several press releases have made ​​known their condolences, including mentions of Charlie Bolden, director of NASA:   

"Sally Ride broke barriers with grace and professionalism -- and literally changed the face of America's space program. The nation has lost one of its finest leaders, teachers and explorers. Our thoughts and prayers are with Sally's family and the many she inspired. She will be missed, but her star will always shine brightly."

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A big Iceberg broke off the Petermann Glacier says NASA

Each zone in Greenland comes to a name very well identified. The Petermann glacier, slides into the sea along the northwestern coast of Greenland, which ends in a giant floating ice tongue. Like other glaciers that end in the ocean, Petermann regularly has small icebergs or ice islands. An iceberg, or the island of ice broke off the Petermann Glacier in 2010. 

Almost two years later, another piece of ice has been released. An enormous iceberg in Greenland shows, another in this occasion. At NASA through Resolution Imaging Spectrometer Moderate (MODIS) aboard the Aqua satellite observed the new iceberg to drift downstream of where they broke the 16th and until July 17, 2012. 

Because Aqua is a polar orbiting satellite, which makes multiple passes over the polar regions every day. At 10:25 Coordinated Universal Time (UTC) on July 16, the iceberg was still near the glacier. At 12:00 UTC the same day (center), Berg had begun to move northward up the fjord. Timing of ice off the island with an area twice the size of Manhattan  A day later, at 09:30 UTC on July 17, Aqua spied a larger opening between the glacier and the iceberg. 

The iceberg seems to have made a slight turn to the left. "The floating extension is collapsing," said Eric Rignot of the Jet Propulsion Laboratory of NASA and the University of California-Irvine. "It's not a collapse, but it is certainly a significant event." Konrad Steffen, director of the Swiss Federal Institute for Forest, Snow and Landscape Research WSL, estimated that the iceberg was about half the size of the ice island that came out of Petermann in 2010. 

If you require more information about these events, you can see the following links.

 Gallery Images from NASA 

MODIS Studies of Greenland

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