NASA is actively monitoring an odd anomaly in Earths magnetic field: a giant region of lower magnetic intensity in the skies above the planet, extending out between South America and southwest Africa.
This huge, developing phenomenon, called the South Atlantic Anomaly, has fascinated and concerned researchers for years, and maybe none more so than NASA scientists. The space firms satellites and spacecraft are especially vulnerable to the weakened magnetic field strength within the abnormality, and the resulting exposure to charged particles from the Sun.The South Atlantic Anomaly (SAA)– compared by NASA to a dent in Earths magnetic field, or a type of pothole in space– usually doesnt impact life on Earth, however the very same cant be said for orbital spacecraft (including the International Space Station), which pass straight through the anomaly as they loop around the planet at low-Earth orbit altitudes.During these encounters, the reduced magnetic field strength inside the anomaly implies technological systems onboard satellites can short-circuit and malfunction if they become struck by high-energy protons emanating from the Sun.These random hits may generally just produce low-level glitches, but they do carry the risk of triggering substantial data loss, or perhaps long-term damage to crucial elements– risks requiring satellite operators to routinely shut down spacecraft systems before spacecraft go into the abnormality zone.Mitigating those threats in space is one reason NASA is tracking the SAA; another is that the secret of the anomaly represents a fantastic opportunity to examine a complex and difficult-to-understand phenomenon, and NASAs broad resources and research study groups are uniquely well-equipped to study the occurrence. ” The electromagnetic field is actually a superposition of fields from numerous present sources,” discusses geophysicist Terry Sabaka from NASAs Goddard Space Flight Centre in Greenbelt, Maryland.The primary source is considered to be a swirling ocean of molten iron inside Earths outer core, countless kilometres listed below the ground. The movement of that mass generates electrical currents that develop Earths magnetic field, but not always consistently, it seems.A big reservoir of thick rock called the African Large Low Shear Velocity Province, located about 2,900 kilometres (1,800 miles) listed below the African continent, interrupts the fields generation, resulting in the dramatic weakening impact– which is assisted by the tilt of the planets magnetic axis.” The observed SAA can be also analyzed as a consequence of compromising supremacy of the dipole field in the region,” states NASA Goddard geophysicist and mathematician Weijia Kuang.” More specifically, a localised field with reversed polarity grows strongly in the SAA region, hence making the field strength extremely weak, weaker than that of the surrounding regions.” Satellite information recommending the SAA is dividing. (Division of Geomagnetism, DTU Space) While theres much researchers still do not fully understand about the abnormality and its implications, new insights are continually clarifying this odd phenomenon.For example, one study led by NASA heliophysicist Ashley Greeley in 2016 revealed the SAA is drifting slowly in a north-westerly direction. Its not just moving, nevertheless. Much more remarkably, the phenomenon appears to be in the process of splitting in 2, with researchers this year discovering that the SAA appears to be dividing into two distinct cells, each representing a separate centre of minimum magnetic intensity within the higher anomaly.Just what that implies for the future of the SAA remains unidentified, but in any case, theres evidence to suggest that the anomaly is not a new appearance.A research study published last month suggested the phenomenon is not a freak event of recent times, however a frequent magnetic occasion that may have affected Earth since as far back as 11 million years ago.If so, that might signal that the South Atlantic Anomaly is not a trigger or precursor to the entire planets magnetic field turning, which is something that actually occurs, if not for hundreds of countless years at a time.Obviously, substantial questions remain, but with a lot going on with this vast magnetic curiosity, its great to know the worlds most powerful area firm is seeing it as closely as they are.” Even though the SAA is slow-moving, it is going through some change in morphology, so its likewise important that we keep observing it by having actually continued missions,” says Sabaka.” Because thats what assists us make designs and predictions.”.


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