The cosmic explosion among the brightest in recorded history occurred at the other end of the Milky Way and reached us on December 27 and last Friday it was reported at a special press conference at NASA headquarters
Image #1: Artist's impression of the event on December 27, 2004. A gamma-ray burst erupted from SGR 1806-20 and hit Earth's atmosphere.
Click here to watch the movie
Scientists discovered a flash of light that came from the other end of the galaxy, and which was so strong that it bounced off the surface of the moon and illuminated the Earth's upper atmosphere.
The light flash was the brightest compared to all the flashes detected by the scientific instruments, and it lasted about a tenth of a second. NASA and European satellites discovered the flare and its results on December 27, 2004. Two teams of scientists reported the event at a special press conference held on Friday, February 18, 2 at NASA Headquarters in Washington. A large number of articles are planned for publication on this topic.
The scientists say that the glow came from a giant flame on the surface of an exotic neutron star - Magnetar. The visible intensity was brighter than the full moon and all the star explosions known in history. The light was also the brightest in the gamma ray energy range, much more energetic than visible light or X-rays and it was not within the range of vision of the human eye.
The eruption did happen at the other end of the Milky Way, but in cosmic terms it is considered relatively close and this raises the question of whether a gamma ray burst, perhaps even larger, damaged our atmosphere and caused one of the massive extinctions known in the history of the Earth and which occurred hundreds of millions of years ago.
Also, if giant flares can be so powerful, then it's possible that some of the gamma-ray bursts (thought to be from black holes in the making) could actually be the products of neutron star explosions in nearby galaxies.
Image 2: Artist's impression of the magnetar SGR 1806-20 and its magnetic field lines. After the first flash, smaller pulses in the data lead to the hypothesis that they are found in hot spots on the magnetar's rotating surface. The data also do not show a change in the rotation rate of the magnet after the initial flash.
Click here to watch the movie
NASA's new Swift satellite and the National Science Foundation's (NSF) Very Large Telescope Array (VLA) were two of the many observatories that observed the event originating from the neutron star SGR 1806-20, about 50 light-years from Earth in the direction of Sagittarius.
"This could be a once-in-a-lifetime opportunity for astronomers as well as for the neutron star," said Dr. David Palmer of Los Alamos National Laboratories, lead scientist on the paper describing the Swift observations. "We only know of two giant flares in the last 35 years, and last December's event was hundreds of times more powerful."
Image 3: Radio data show a very active region around SGR1806-20. The very large array of telescopes watched material eject from the magnetar as it flew out into interstellar space. These observations at radio wavelengths began seven days after the blaze and continued for about twenty days. They show that SGR1806-20 fades in the radio spectrum.
Credit: NRAO/CfA/Gaensler & Univ. of Hawaii.
Dr. Brian Gaensler of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, is the lead researcher on the report that described the results of the VLA, which tracked the materials from the bone as they were blown into interstellar space. Other major scientific teams are the institutes that operate radio telescopes in Australia, the Netherlands, Great Britain, India and the USA as well as NASA's High Energy Solar Spectroscopic Imager (RHESSI).
A neutron star is the nucleus left over from a star that was once several times more massive than the Sun. When such a star exhausts its nuclear fuel, it explodes in an event known as a supernova. The remaining core is compressed, spins rapidly, has a high magnetic intensity and is only about 25 kilometers in diameter. Millions of neutron stars are known in our Milky Way galaxy.
In picture 4: SGR 1806-20 is an ultramagnetic neutron star, called Magnetar, and it is 50 thousand light-years away from Earth in the direction of Sagittarius.
Click here to watch the movie
Credit: NASA
Scientists have so far discovered about a dozen ultramagnetic stars, called Magnetar. The magnetic field around Magnetar is about a thousand trillion gauss, strong enough to tear the data strip on a credit card if it happened halfway to the moon. Normal neutron stars measure in the order of a trillion gauss. The Earth's magnetic field is about half a gauss strong.
Four of the magnetars, which are also called soft gamma repeaters (SGR) because their flames erupt randomly and release gamma rays. Such events release powers of 10 to the 30th power to 10 to the 35th power watts per second, or energy millions of times stronger than that of the Sun. For example, a rich second, Behak SGR 1806-20 with a power of 10 and a power of 40 watts. The total energy produced by our sun in 150 thousand years.
A scientist from Ben-Gurion University observed about 3 years ago the phenomenon of the brightest energy flash eruption that occurred in the modern era
The amazing phenomenon was observed in space by NASA scientists and European satellites at the end of December 2004
A scientist from Ben-Gurion University, Prof. David Eichler from the Department of Physics, predicted about three years ago that a phenomenon similar to the one observed by the scientists of the American space agency NASA and European satellites on December 27, 2004, might occur in space. At that time, the scientists reported the bright energy flash The most that has occurred so far in the modern era beyond the solar system. This is a tremendous burst of high-energy radiation - defined as the brightest radiation in the gamma radiation field, which is much more energetic than the visible part of the spectrum and the X-ray field.
In addition to this, the interstellar medium was caused by a shockwave that emitted radio waves, created by an eruption on the surface of a neutron star known to researchers as SGR 1806-20, located about 50,000 light years from Earth in the constellation Sagittarius. Scientists have previously discovered about a dozen such neutron stars. They are called magnetars because their magnetic fields are extremely powerful.
In an article he published in 2002, in the Monthly Notices of the Royal Astronomical Society, Eichler theoretically tested the possibility of the occurrence of "a super-giant version of the soft gamma-ray bursts observed so far". In his conclusions, he predicted in advance that such an eruption would be 100 times stronger than those previously observed. Prof. David Eichler and Dr. Yuri Liubarsky from the Department of Physics at Ben-Gurion University of the Negev are among two groups of researchers whose articles on this topic will be published in the upcoming issue of the prestigious scientific journal Nature.
It should be noted that the strength of the magnetic field around Magnetar is around 1,000 trillion (1015) Gauss - strength that is enough to change the shape of atoms and even affect the properties of empty space. (For comparison, normal neutron stars have fields with a strength of "only" one trillion gauss. The Earth's magnetic field is 0.5 gauss). Four of the magnetars are called "soft gamma repeaters, or SGR" because they sometimes erupt and release relatively low-energy ("soft") gamma rays. Amazingly, the last event was 100 times brighter than the brightest of all the massive radiation bursts observed before. The scientists rushed to find an explanation for the intensity of the energy that was released. "Maybe this is the 'big boom' we've been waiting for," says Prof. Eichler. Four years ago, Eichler published an article entitled: "Waiting for the 'Big Boom': A New Type of Outbursts from Old Sources of Soft Gamma Rays?". This article anticipates and describes events such as the December 27 eruption.
"The assumption is based on the well-known principle that magnetic fields of a medium capable of moving are unstable," explains Eichler. "This can be noticed when two small magnets are placed so that their magnetic fields are arranged in the same direction. If the magnets are close together they will reverse relative to each other, so the total magnetic energy will decrease. If we apply the same principle to stars with strong magnetism, we can imagine that large parts of the star will rotate relative to each other, if the strength of the magnetic field is large enough. In such a case, a significant part of the total magnetic energy will be released in a single eruption (while erasing a large part of the magnetic field) and a relatively large amount of energy will be wasted on restructuring the surface of the star." Indeed, the star's magnetic field showed a completely different profile after the December 27 outburst.
Dr. Brian Gensler from Harvard University's Center for Astrophysics and the Smithsonian Institution wrote in Nature about the radio wave radiation caused by the eruption, which tracked the material ejected into interstellar space. Scientists from 20 research institutions joined the observations. "The second strongest eruption observed from a soft gamma-ray source was negligible compared to the amazing eruption of December 27," Gensler says. "If it had happened 10 light years away from us, there would have been serious damage to our atmosphere, which would have led to a mass extinction. Fortunately, there are no magnetars near us."
The Israeli research is supported by the Israel-USA Binational Science Foundation, the National Science Foundation, the Israel-German Foundation, the Arnaud Chair of Theoretical Physics and the Ministry of Absorption.
For an article on the NASA website containing entries for additional films
