[ad_1]
Earth is a huge magnet, its iron-rich core creating a shield of magnetic field that envelops the planet – well, almost. A “bump” in this magnetic field known as the South Atlantic Anomaly allows charged particles from the sun to dive closer to the planet in an area above South America and the ocean. South Atlantic.
These particles, at the very least, can spoil the instruments in space. NASA scientists and other researchers therefore have no choice but to adapt to this hiccup of the magnetic field, by turning off the satellite instruments that pass through the AAS and accepting the loss of some data on instruments aboard the International Space Station (ISS). They are also closely monitoring SAA, according to a new article from NASA Goddard Space Flight Center.
Related: What if the Earth’s magnetic field disappeared?
“Even though AAS is slow, it undergoes a change in morphology, so it’s also important that we continue to observe it,” Terry Sabaka, a geophysicist at Goddard, Md., Said in the article.
The anomaly
Earth’s magnetic field is the product of its iron-rich outer core, which creates the field as it swirls around the inner core. The field protects the Earth’s atmosphere from being slowly removed by charged particles from the sun. It also protects electronic equipment on Earth from this same bombardment.
Normally, particles from the sun are either deflected by the field or trapped in two areas called the Van Allen belts, which allow particles to within about 644 kilometers of the Earth’s surface. This provides plenty of space to protect the planet and its human-launched satellites. The ISS, for example, spins about 350 km above the Earth’s surface.
But the magnetic field is weakening, which some scientists think could be about to reverse, exchanging its north and south poles. (Alternatively, it could go through a weak phase and then strengthen again, as has happened in the past.) The zero point of this weakening appears to be the South Atlantic anomaly, a strange place of weakness. particular that stretches between South America and Africa. The area is changing, recent research suggests it is expanding not one, but two separate low points.
Related: 7 ways the Earth changes in the blink of an eye
Already, satellites passing through the SAA must do so with many sensitive instruments turned off, according to Goddard. As the ISS passes through it, some of the space station’s instruments are vulnerable to “blips” caused by increased exposure to solar particles. The Global Ecosystem Dynamics Investigation (GEDI) mission, for example, undergoes a power reset about once a month and loses a few hours of data each time thanks to the SAA.
Fortunately, “these events are not causing any harm to GEDI,” Bryan Blair, deputy principal mission researcher and lidar instrument scientist at Goddard, said in the agency article.
Track changes
Goddard scientists and their colleagues around the world are keeping an eye on AAS, both to make sure their operations are protected from its effects and to try to understand how the anomaly will change in the future.
Using data from SAMPEX (the Solar Anomalous and Magnetospheric Particle Explorer), a satellite that was launched in 1992 and collected data until 2012, Goddard researchers learned that SAA is drifting slightly west, results published in the journal Space weather in 2016. The European Space Agency (ESA) launched a set of satellites called Swarm in 2013 that provide detailed observations of the Earth’s magnetic field and changes in AAS. It was data from the Swarm satellites that showed the development of two distinct minimum force points in the SAA, suggesting that the anomaly could split into two distinct areas.
Analyzing this data allows satellite engineers to design their satellites to withstand the amount of solar radiation they are likely to encounter once in orbit, according to Goddard. The researchers are also combining observational data with models of the Earth’s central dynamics to try and predict what the anomaly will do next.
“This is similar to how weather forecasts are produced, but we work with much longer timescales,” Andrew Tangborn, mathematician at Goddard’s Planetary Geodynamics Laboratory, said in the Goddard article.
Meanwhile, researchers outside of NASA are working to understand the links between the motion of the outer core and the characteristics of the magnetic field it produces. Researchers at the University of Liverpool in England recently reported that volcanic rocks made from lava that erupted long ago on the Atlantic island of St. Helena show magnetic anomalies 8 to 11.5 million years old, suggesting that this area of the South Atlantic anomaly has been unstable for millions of years.
Originally posted on Live Science.
[ad_2]
Source link