More than 10 years of measurements from three Earth-orbiting observatories show that weak areas of Earth’s protective magnetic field are expanding, exposing orbiting satellites and astronauts to more solar radiation.
Observations by the European Space Agency’s Swarm 3 satellite show that Earth’s already weak magnetic field over the South Atlantic Ocean, a region known as the South Atlantic Anomaly (SAA), has worsened, expanding since 2014 to an area half the size of continental Europe. At the same time, measurements showed that an area over Canada with an especially strong magnetic field is shrinking, while another area of strong magnetic fields in Siberia is expanding.
you may like
geomagnetism
The three satellites were launched in 2014 to precisely monitor magnetic signals from Earth’s core and mantle, ionosphere and magnetosphere. Earth’s magnetic field (technically known as geomagnetism) is thought to be generated by a rotating core of molten iron about 2,900 kilometers (1,800 miles) beneath our feet. However, the strength of this field is continuously changing, and scientists are still studying the exact mechanism.
Earth’s magnetic field protects life on the Earth’s surface from harmful charged particles in solar radiation. During the occurrence of auroras, such as the aurora borealis, we can see the effect of charged particles from the sun interacting with the earth’s magnetic field in the upper atmosphere.
Because the Earth’s magnetic field extends far into space, it also protects spacecraft in orbit, including most satellites and the International Space Station (ISS). However, the study authors cautioned that spacecraft and astronauts entering weak spots in the South Atlantic Ocean while orbiting Earth could be exposed to more radiation.
For spacecraft hardware, this radiation can cause further malfunctions, damage, and even power outages. “The primary impact is on our low-orbit satellite infrastructure,” Finley said. “These satellites experience higher rates of charged particles when passing through regions of weak electric fields, which can cause problems for electronic equipment.”
Danger to astronauts
Those in orbit will also face increased risks from radiation, including increased chances of developing DNA damage and cancer during their lifetime. “Astronauts will also experience these charged particles, but their time in orbit is shorter than the lifetime of most low-Earth orbit satellites,” Finley said. (On average, ISS astronauts spend about six months in low Earth orbit, while satellites typically spend more than five years there, or about 10 times that amount.)
Earth’s magnetic field is relatively weak compared to more familiar magnetism, with strengths ranging from approximately 22,000 to 67,000 nanoTesla. By comparison, a typical refrigerator magnet has a strength of about 10 million nanoTeslas.
In SAA, the geomagnetic strength is less than 26,000 nanoTesla. According to the study, the area of this region has increased by almost 1% of the Earth’s surface area since 2014. SAA’s weakest point is currently measured at 22,094 nanoteslas, down 336 nanoteslas from 2014.
you may like
In areas of strong geomagnetism in northern Canada, the strength exceeds 57,000 nanoteslas. The study found that its area has shrunk by 0.65% of Earth’s surface area, while its strongest point has fallen to 58,031 nanoteslas, a decrease of 801 nanoteslas from 2014. In contrast, the Siberian high-field region has expanded in size, increasing in area by 0.42% of Earth’s surface area, and the maximum electric field strength has increased by 260 nanoteslas since 2014 to 61,619 nanoteslas today.
Image 1/2
These changes in the Northern Hemisphere were unexpected, Finley said. “This is related to the circulation pattern of liquid metal in the core, but the exact cause is unknown,” he said.
However, the study found no signs of an impending magnetic field reversal. Although Earth’s magnetic field has already reversed hundreds of times, “we know from the paleomagnetic record that Earth’s magnetic field has weakened many times in the past, exhibiting regions of weak magnetic field such as the South Atlantic Anomaly without reversing,” Finlay said. “We are likely to see fluctuations in timescales ranging from 10 to 100 years in this field.”
“Enhanced” spaceship
The increased danger from solar radiation to satellites and astronauts passing over SAA could be reduced by “hardening” spacecraft to withstand it, Finlay said. [so] This must be taken into account when designing future missions. ”
Hagai Amit, a geophysicist at the University of Nantes in France who was not involved in the latest study but studies SAA, noted that while several scientists have proposed possible reasons for the observed changes in Earth’s magnetic field, the actual mechanism remains unclear. “whole, [the authors] “We have convincingly demonstrated that continuous, high-quality geomagnetic measurements are important for providing important insights into deep Earth dynamics,” he told Eos via email.
This article was originally published on Eos.org. Read the original article.
Source link
