Much larger solar corona than previously observed Karen C. Fox
NASA's Goddard Space Flight Center
Wed, 25 Jun 2014 22:45 CDT
NASA's Goddard Space Flight Center
Wed, 25 Jun 2014 22:45 CDT
© NASA/STEREO
Scientists used these observations of the sun's atmosphere (the bright light of the sun itself is blocked
by the black circle at the middle) from NASA's Solar Terrestrial Relations Observatory on Aug. 5, 2007,
to define the outer limits of the solar atmosphere, the corona.
Scientists used these observations of the sun's atmosphere (the bright light of the sun itself is blocked
by the black circle at the middle) from NASA's Solar Terrestrial Relations Observatory on Aug. 5, 2007,
to define the outer limits of the solar atmosphere, the corona.
Surrounding the sun is a vast atmosphere of solar particles, through which magnetic fields swarm, solar flares erupt, and gigantic columns of material rise, fall and jostle each other around. Now, using NASA's Solar Terrestrial Relations Observatory, scientists have found that this atmosphere, called the corona, is even larger than thought, extending out some 5 million miles above the sun's surface -- the equivalent of 12 solar radii. This information has implications for NASA's upcoming Solar Probe Plus mission, due to launch in 2018 and go closer to the sun than any man-made technology ever has before.
These STEREO observations provide the first direct measurements of the inner boundary of the heliosphere -- the giant bubble sparsely filled with solar particles that surrounds the sun and all the planets. Combined with measurements from Voyager 1 of the outer boundary of the heliosphere, we have now defined the extent of this entire local bubble.
"We've tracked sound-like waves through the outer corona and used these to map the atmosphere," said Craig DeForest of the Southwest Research Institute in Boulder, Colorado. "We can't hear the sounds directly through the vacuum of space, but with careful analysis we can see them rippling through the corona."
The results were published in The Astrophysical Journal on May 12, 2014. The researchers studied waves known as magnetosonic waves, and they are a hybrid of sound waves and magnetic waves called Alfven waves. Unlike sound waves on Earth, which oscillate several hundred times per second, these waves oscillate about once every four hours -- and are about 10 times the length of Earth.
Read the rest of the article at : http://www.sott.net/article/280960-Much-larger-solar-corona-than-previously-observed
These STEREO observations provide the first direct measurements of the inner boundary of the heliosphere -- the giant bubble sparsely filled with solar particles that surrounds the sun and all the planets. Combined with measurements from Voyager 1 of the outer boundary of the heliosphere, we have now defined the extent of this entire local bubble.
"We've tracked sound-like waves through the outer corona and used these to map the atmosphere," said Craig DeForest of the Southwest Research Institute in Boulder, Colorado. "We can't hear the sounds directly through the vacuum of space, but with careful analysis we can see them rippling through the corona."
The results were published in The Astrophysical Journal on May 12, 2014. The researchers studied waves known as magnetosonic waves, and they are a hybrid of sound waves and magnetic waves called Alfven waves. Unlike sound waves on Earth, which oscillate several hundred times per second, these waves oscillate about once every four hours -- and are about 10 times the length of Earth.
Read the rest of the article at : http://www.sott.net/article/280960-Much-larger-solar-corona-than-previously-observed
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