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What is a Geomagnetic Storm?
January 15, 2023 at 07:05 PM EST
By WeatherBug's Ali Husain
A geomagnetic storm is officially described as when “a major disturbance of Earth’s magnetosphere that occurs when there is a very efficient exchange of energy from the solar wind into the space environment surrounding Earth”. That definition is a bit wordy, so let’s break it down more.
First, we have the Earth’s magnetosphere. This is the magnetic field that surrounds the Earth in a comet-shaped bubble, shielding the planet from cosmic and solar radiation that is harmful to life. Several planets in our solar system have magnetospheres, but Earth’s is the strongest. This magnetic field is a crucial element to Earth’s habitability, by us or other living organisms.
How is this magnetic field generated? Deep within the Earth, electrically charged molten iron churns around our solid core, generating a magnetic field that reaches deep into space. On the side of Earth facing the sun, the magnetosphere extends about six to ten times the radius of Earth. On the nightside, the field extends in a long tail, like the shape of a giant comet. The length of the magnetosphere on the nighttime side varies, but can measure hundreds of Earth radii away, far past the moon (about 60 Earth radii away).
The next step is understanding solar wind, which is created by the outwards expansion of charged particles (plasma) from the Sun’s corona (outermost layer). This plasma gets heated and heated to the point that the Sun’s gravity can’t hold it down, at which point it is ejected from the surface of the Sun.
In order for the solar wind to efficiently interact with the Earth’s magnetosphere and cause a geomagnetic storm, the necessary speed, duration and direction of the solar wind is crucial. High-speed solar winds lasting for several hours are needed to create a geomagnetic storm, and a southward-directed solar wind magnetic field (which opposes the direction of Earth’s magnetic field) at the dayside of the magnetosphere. When these conditions are met, energy is much more easily transferred from the solar wind into the Earth’s magnetosphere.
The largest geomagnetic storms are typically associated with coronal mass ejections (CMEs), where around a billion tons of plasma travels along the sun’s magnetic fields towards Earth. While many CMEs will take several days to arrive at Earth, the most intense storms can arrive in as little as 18 hours.
During these storms, the uppermost layers of our atmosphere can get heated above normal and expand, causing extra drag on satellites in low-Earth orbit. The heating can also modify and disrupt the path of radio signals, create errors in GPS systems and create harmful geomagnetic induced currents in the power grid and in pipelines. There is one benefit, however: the gorgeous aurora borealis and aurora australis, which occur at high latitudes and light up the night sky during a geomagnetic storm.
So, there you have it; a detailed explanation of a peculiar type of storm, possible ramifications, and a resoundingly beautiful light display above the poles as a result of geomagnetic storms. Stay tuned this week for more details on what you can do to be ready for a geomagnetic storm.
Source: NOAA, NASA, Maine.gov
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Story Image via Pixabay
First, we have the Earth’s magnetosphere. This is the magnetic field that surrounds the Earth in a comet-shaped bubble, shielding the planet from cosmic and solar radiation that is harmful to life. Several planets in our solar system have magnetospheres, but Earth’s is the strongest. This magnetic field is a crucial element to Earth’s habitability, by us or other living organisms.
How is this magnetic field generated? Deep within the Earth, electrically charged molten iron churns around our solid core, generating a magnetic field that reaches deep into space. On the side of Earth facing the sun, the magnetosphere extends about six to ten times the radius of Earth. On the nightside, the field extends in a long tail, like the shape of a giant comet. The length of the magnetosphere on the nighttime side varies, but can measure hundreds of Earth radii away, far past the moon (about 60 Earth radii away).
The next step is understanding solar wind, which is created by the outwards expansion of charged particles (plasma) from the Sun’s corona (outermost layer). This plasma gets heated and heated to the point that the Sun’s gravity can’t hold it down, at which point it is ejected from the surface of the Sun.
In order for the solar wind to efficiently interact with the Earth’s magnetosphere and cause a geomagnetic storm, the necessary speed, duration and direction of the solar wind is crucial. High-speed solar winds lasting for several hours are needed to create a geomagnetic storm, and a southward-directed solar wind magnetic field (which opposes the direction of Earth’s magnetic field) at the dayside of the magnetosphere. When these conditions are met, energy is much more easily transferred from the solar wind into the Earth’s magnetosphere.
The largest geomagnetic storms are typically associated with coronal mass ejections (CMEs), where around a billion tons of plasma travels along the sun’s magnetic fields towards Earth. While many CMEs will take several days to arrive at Earth, the most intense storms can arrive in as little as 18 hours.
During these storms, the uppermost layers of our atmosphere can get heated above normal and expand, causing extra drag on satellites in low-Earth orbit. The heating can also modify and disrupt the path of radio signals, create errors in GPS systems and create harmful geomagnetic induced currents in the power grid and in pipelines. There is one benefit, however: the gorgeous aurora borealis and aurora australis, which occur at high latitudes and light up the night sky during a geomagnetic storm.
So, there you have it; a detailed explanation of a peculiar type of storm, possible ramifications, and a resoundingly beautiful light display above the poles as a result of geomagnetic storms. Stay tuned this week for more details on what you can do to be ready for a geomagnetic storm.
Source: NOAA, NASA, Maine.gov
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Story Image via Pixabay