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While major geomagnetic storms are rare, with only a few recorded per century, there is significant potential for large-scale impacts when they do occur, and they can present substantial hazards to national security and the economy.

Space Weather and Magnetic Storms

The Sun – a flaming ball of gas at the center of our solar system that makes life on Earth possible – isn’t what you’d normally think of as being an object in space that's “in our neighborhood.” At just under 94 million miles away, it’s hard to imagine something that far away impacting our home planet with anything more than the light and heat required to sustain life…but you’d be wrong. We all deal with weather conditions every single day like snow, rain, wind, sun, and humidity. But did you know that the Earth experiences another type of weather? Massive flows of charged particles that originate on the Sun burst outward into the solar system at speeds reaching just over 2 million miles an hour! This stream of particles is called the “solar wind,” and it slams into any solar-system objects in its path, including the Earth.

Image showing solar wind interfering with Earth's magnetic field.
Image showing solar wind interfering with Earth's magnetic field. (Used with permission from the European Space Agency)

Sounds pretty dramatic, right? Here’s the kicker: This sort of thing happens all the time! We just don’t normally know anything about it, unless you’re one of the lucky ones who live near an area that experiences the Aurora Borealis, more commonly known as the “northern lights.” In fact, there’s a name for this kind of galactic phenomena: “space weather.” When waves of solar wind shoot out from the Sun and hit the Earth’s magnetic field, that interaction is called a “magnetic storm,” and these storms can have some serious consequences if we aren’t paying attention and don’t prepare accordingly. The role of geophysicists is to research the ground effects of these magnetics storms, so communities can prepare for and protect themselves from the potentially crippling effects they can cause.

Aurora borealis display evokes the beauty of the Arctic
Aurora borealis display evokes the beauty of the Arctic, as well as the geomagnetic field intensity actively monitored by USGS scientists.

Earth is somewhat protected from these raging cosmic blusters by its magnetic field, which is generated deep in the core of our planet, and it extends beyond Earth’s atmosphere by some tens of thousands of miles. The extent of the geomagnetic field in space is known as the "magnetosphere." While the magnetosphere offers some protection, if the geomagnetic storm is large enough and forceful enough, the impacts on the ground can have far-ranging consequences.

The mission for USGS scientists is to monitor the Earth's magnetic field using ground-based observatories and instruments, which provide continuous records of magnetic field variations covering long timescales; map what are called “geoelectric fields” in the Earth to determine the nature and character of ground-level geomagnetic hazards; disseminate magnetic data to various governmental, academic, and private institutions; and conduct research into the nature of geomagnetic variations.

Here's a fun and fascinating resource called, “Journey Along a Fieldline,” which introduces the basics of geomagnetism using an incredibly popular medium: the comic book.


Ok, Space Weather and Magnetic Storms Happen All the Time. So What?

While major geomagnetic storms are rare, with only a few recorded per century, there is significant potential for large-scale impacts when they do occur, and they can present substantial hazards to national security and the economy because of their potential disruptions to national power grids and other electro-magnetic platforms and utilities.

In addition to electric-power grids, space weather can interfere with radio communications, military and civilian navigational systems, satellites, airline activity, and directional oil and gas drilling.

A schematic depiction of coronal mass ejection headed toward the Earth and its surrounding magnetosphere. Graphic courtesy of NA

For instance, in March of 1989, one of the most intense magnetic storms of the twentieth century occurred when rapid magnetic field variations from a geomagnetic storm caused wide-spread blackouts across the Canadian Hydro-Quebec power grid, resulting in the loss of electric power to more than 6 million people (For more information past events, check out this list of “Magnetic Disturbance Events” for the past two decades). The same storm caused widespread interference to power grids in the United States, including damaging a high-voltage transformer at a nuclear power plant. Some studies anticipate that an even more intense magnetic superstorm could cause widespread loss of electricity in the United States – an event that would carry significant economic cost.

Silhouette of high-voltage power lines against the sun.
Silhouette of high-voltage power lines against the sun. Credit: Dreamstime

The unique role of the USGS includes monitoring space weather on the ground, to include researching the physical causes and effects of magnetic storms. Our scientists develop useful products for real-time situational awareness (e.g., maps of geomagnetic activity, and geoelectric hazards.) and assess the hazardous effects of magnetic storms by monitoring the Earth’s magnetic field at 14 ground-based observatories positioned across the United States and its territories.

Map from the report showing 100-year storm-induced voltages on the national electric power grid
Map from the report showing 100-year storm-induced voltages on the national electric power grid.

USGS geophysicists constantly monitor Earth’s magnetic field, providing information on magnetic storm frequency and intensity, and some USGS observatories have operated continuously for over 100 years. Check out this brief article to learn more about the USGS’s ground-based monitoring operations.


The Importance of Partnerships and Looking Forward to the Future

Of course, the United States isn’t the only country on the planet that must prepare for these types of space-based storms. Magnetic storm-related hazards impact the entire planet, so the USGS works in concert with dozens of partners around the world. Here’s a brief overview of each country-partner and a link to their individual programs, so you can get a better sense of the global effort to understand space weather phenomena. Additionally, check this page for the International Real-Time Magnetic Observatory Network, which is a global network of observatories that monitor the Earth’s magnetic field founded in-part by the USGS. Here you can find data and information from magnetic observatories around the world.

With an increasingly interconnected global infrastructure that handles everything from energy production and distribution, to international commerce and trade, to social media and the latest sports highlights, our technological platforms are all potentially vulnerable to interference generated by intense magnetic storms. Consequently, the science of geomagnetism is more important today than at any point in the discipline's long and colorful history.

Along with its distinguished past, the future of geomagnetic research is promising and vibrant. In response to the rapidly evolving science of geomagnetism and the ever more stringent demands of the scientific community, the USGS Geomagnetism Program is constantly upgrading and modernizing the observatory network, and in the future, USGS geophysicists will monitor the magnetic field at higher frequencies, in addition to gradually expanding the observatory network in collaboration with allied agencies. Additionally, our scientists are undertaking new scientific research and product development focused on characterizing the complicated behavior of the Earth's magnetic field in space and time, especially during magnetic storms.

globe with triangle symbols and labels for geomagnetic observatory locations
Map of USGS Magnetic observatory locations.

Additional Resources for Further Exploration

A 100-year geoelectric hazard analysis for the U.S. high-voltage power grid: Using magnetic observatory monitoring data and magnetotelluric survey data, USGS scientists have mapped geoelectric hazards that can be generated by rare, but very intense magnetic superstorms.

The Geoelectric Field Model: 1-Minute Model: The NOAA-USGS Geoelectric Field Model calculates regional geoelectric field levels in the U.S. caused by disturbances in Earth’s magnetic field and its interaction with the solid Earth. The near real-time data (refreshed every minute) indicates the level of space weather impact affecting the electrical power grid to help operators mitigate effects on critical infrastructure.

For additional information about geomagnetic research and study, check out the USGS’s Geomagnetic FAQ page for more on this fascinating area of USGS science.

Image: San Juan Geomagnetic Observatory
Cayey, Puerto Rico geomagnetic observatory.


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