I’m sure everyone has heard about The Bermuda Triangle, a place on earth where mysteriously ships and planes used to disappear, so you can associate “bermuda” to something peculiar or unusual. There’s a similar place in space where out of the sudden electronic gadgets crash and there are malfunctions and satellite failures and it also affects the people in the satellites. It is known as the ‘The Bermuda Triangle of Space’ or ‘The South Atlantic Anomaly (SAA)’ and is one of the most dangerous areas of radiation ever encountered.
South Atlantic Anomaly Location |
SAA is a few hundred kilometres above the coast of Brazil, it is the point where the Van Allen radiation belts – rings of charged particles that surround Earth – come closest to the planet’s surface. When the belts were discovered in the 1950s, scientists suspected the SAA could pose some risk.
Astronauts’ on the space shuttle complained laptop computers would sometimes crash when they passed through the anomaly. Astronauts are also affected by this region, which is said to be the cause of peculiar ‘shooting stars’ (phosphenes) seen in the visual field of astronauts, produced by radiation directly stimulating the retina of astronauts.
Some spacecraft, such as the Hubble Space Telescope, are even programmed to switch off their delicate instruments as they fly through the area to avoid damage.The International Space Station has also been given extra shielding to deal with this problem.
The South Atlantic Anomaly (SAA) is an area which exposes orbiting satellites to higher-than-usual levels of radiation. |
WHAT IS THE SAA?
The Earth is surrounded by a pair of concentric donut-shaped clouds called the Van Allen radiation belts (The Van Allen radiation belt is a torus of energetic charged particles (i.e. a plasma) around Earth, trapped by Earth’s magnetic field. The Van Allen belts are closely related to the polar aurora where particles strike the upper atmosphere and fluoresce.) which, like magnetic bottle, store and trap charged particles from the solar wind. They are aligned with the magnetic axis of the Earth, which is tilted by 11 degrees from the rotation axis of the Earth, and are not symmetrically placed with respect to the Earth’s surface. Although the inner surface is 1200 – 1300 kilometers from the Earth’s surface on one side of the Earth, on the other they dip down to 200 – 800 kilometers. Above South America, about 200 – 300 kilometers off the coast of Brazil, and extending over much of South America, the nearby portion of the Van Allen Belt forms what is called the South Atlantic Anomaly. Satellites and other spacecraft passing through this region of space actually enter the Van Allen radiation belt and are bombarded by protons exceeding energies of 10 million electron volts at a rate of 3000 ‘hits’ per square centimeter per second. This can produce ‘glitches’ in astronomical data, problems with the operation of on-board electronic systems, and premature aging of computer, detector and other spacecraft components.Off the coast of Brazil, and extending over much of South America, the nearby portion of the Van Allen Belt forms what is called the South Atlantic Anomaly. Satellites and other spacecraft passing through this region of space actually enter the Van Allen radiation belt and are bombarded by protons exceeding energies of 10 million electron volts at a rate of 3000 ‘hits’ per square centimeter per second. This can produce ‘glitches’ in astronomical data, problems with the operation of on-board electronic systems, and premature aging of computer, detector and other spacecraft components.
Sorry couldn’t find a better one, so to view please click on the picture. |
Van Allen Radiation Belt |
Riccardo Campana at the National Institute for Astrophysics in Bologna, Italy, has analysed radiation data from an X-ray-monitoring satellite called BeppoSAX, which was active from 1996 to 2003.
They found that radiation levels in the lower layer of the SAA were much less than in the upper layers. They also saw that the anomaly is slowly moving westwards. The team is now designing a space telescope that will orbit through the lower part of the danger zone, which is not well studied.
Quite informative, Dirgh. Great!
Yes very informative…keep it up.
Waiting for your new blog.
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Very informative Dirgh. Keep blogging. Ritu
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