Coronal Mass Ejections (CMEs): colossal eruptions releasing approximately a billion tons of scorching plasma from the Sun at staggering speeds. While many of these phenomenal bursts venture off in directions distant from our home planet, there are moments when the trajectories of the Sun and Earth ominously align. But does this mean that every CME poses a potential peril to our world?
Are all CMEs a threat to Earth? Not all CMEs threaten Earth. Their potential harm hinges on magnetic alignment. Specifically, when a CME’s magnetic field opposes Earth’s, it can induce geomagnetic storms. Conversely, when aligned similarly, the CME largely bypasses Earth without significant effect.
Diving deep into the cosmic dance between Coronal Mass Ejections (CMEs) and our home planet, we unravel the mysteries of these solar phenomena and their potential impact on Earth’s intricate electrical infrastructure.
Are There Different Varieties of CMEs?
Recommended Reading: What Are CMEs? and How Much Time Do We Have Before a G5 Geomagnetic Storm Hits After a Solar CME?
Throughout the years, space scientists and physicists have extensively studied CMEs, leading them to believe there might be distinct types. A shared characteristic among all CMEs is their bubble-like structure.
Although the scientific community remains uncertain, there’s a prevailing theory suggesting two primary types of CMEs. The first, characterized by a distinct loop, is referred to as the Loop-type Coronal Mass Ejections (source). The second, associated with a blast, has been termed Blast-associated Coronal Mass Ejections (BCME).
Loop-Type Coronal Mass Ejections (LCME)
A Loop-Type Coronal Mass Ejections (LCME) is distinctively recognized by its position on the solar surface. Featuring two separate foot points, it often induces an arcade of flares between these points.
Characteristics that distinguish an LCME from other CME types include:
- The presence of a frontal loop, although infrequent.
- A discernible cavity.
- A core or gas that ascends, accompanied by a dark filament.
- Two stable foot points.
- Some showcase loop structures connecting the flare region to where the points were anchored on the Sun pre-flare.
- An outward acceleration.
- A density enhancement exceeding that of the regular corona.
Blast-Associated Coronal Mass Ejections (BCMEs)
BCMEs are set apart from other CMEs by several features, such as:
- A dome-like structure that emanates outward from a solar storm.
- Being the most probable type to instigate a flare-blast wave.
- Propagation at a consistent velocity.
- A density enhancement is considerably lower than that of an LCME.
Contemporary Perspectives on Various Types of CMEs
Subsequent research suggests that dynamic and kinematic behaviors serve as differentiating factors among CMEs. Space physicists theorize that specific physical rationale distinguishes one Coronal Mass Ejection from another.
This rationale also plays a pivotal role in determining their behaviors as they emanate from the Sun. The temporal relationship between flares and CMEs is of particular interest to scientists.
Understanding the precise onset time of a CME at the Sun and the ensuing solar flares is crucial. Notably, when a CME manifests after a solar flare, its velocity diminishes. Conversely, ejections that transpire prior to solar flares tend to accelerate, increasing in speed.
Recommended Reading: How Big Are Coronal Mass Ejections (CMEs)? and What To Do Before a G5 or Greater Geomagnetic Storm?
Why Coronal Mass Ejections Don’t Necessarily Spell Doom
While there’s consensus on the existence of multiple types of CMEs – some scientists propose two, others argue for as many as four – what’s clear is that their kinetics and dynamics differentiate them upon their emergence from the Sun.
Importantly, not every CME implies impending doom for Earth and its inhabitants. Based on sustained observations, a combination of three specific factors must concurrently manifest for a significant threat to arise:
- Appropriate Magnetic Alignment
Space weather events, influenced by the Sun’s activities, are rendered harmless to Earth unless they align magnetically with our planet’s magnetic field. Such alignment facilitates the penetration of Coronal Mass Ejections into Earth’s magnetosphere.
Earth is not defenseless; it boasts protective mechanisms, primarily its magnetic field. If this magnetic alignment is misaligned, Earth’s magnetic field benignly deflects CMEs and other solar particles. Those particles that aren’t deflected typically result in harmless yet mesmerizing aurora borealis displays.
- The Connection of Solar Prominence With Solar Flares
While solar flares typically manifest within the Sun’s photosphere, or visual surface, not every solar flare will trigger a Coronal Mass Ejection. A flare needs to interact directly with the solar corona for a CME to occur (source).
CMEs that have this direct interaction are also often linked by solar prominence. Although a solar flare alone, with at its worst, blackouts in navigation systems and communication signals, won’t inflict theoretically tremendous harm on Earth.
CMEs, on the other hand, when moving rapidly and aimed directly at Earth, can pose significant risks.
- The Existence of Extensive Electrical Infrastructure
For CMEs to inflict significant damage, a vast electrical infrastructure must be present. Specifically, power grids, with wires, transformers, sprawling electrical coils, and loops across extensive areas, on the planet provide the ideal conditions for CMEs to cause havoc to humans.
In the 1859 Carrington event, many parts of the United States had yet to be connected to the power grid. Consequently, the lack of widespread electrical wires limited the potential damage CMEs could inflict.
While CMEs, regardless of their type, have the potential to wreak havoc on Earth, their capacity to cause such destruction hinges on the simultaneous presence of the three factors mentioned above.
To put it into perspective, the Sun’s activities, which have persisted since time began, frequently result in solar flares, leading to Coronal Mass Ejections.
For the most part, CMEs primarily result in breathtaking auroral displays. Yet, the immense infrastructure development characterizing the modern world does raise valid concerns. The threat, given the right conditions, is palpable and real.
The Dangers of Geomagnetically Induced Current To Electrical Infrastructure and Power Grids
Since the early 19th century, space scientists have concurred on a foundational principle: the concept of induced current.
There is definitely a possibility of dangers of geomagnetically induced current to electrical infrastructure and power grids, as discussed by NOAA in their article “Space Weather and Safety.”
NOAA Points out in the article that powerful geomagnetic storms could cause significant power outages that may have cascading effects.
The cascading effects in the order below caused by Geomagnetically Induced Current power grid shutdowns could cause the following losses:
- Satellite networks and GPS services.
- All electrical systems that do not have back-up power.
- Computer systems, telephone systems, and communications systems.
- Electrical heating/air conditioning and lighting systems.
- Perishable foods and medications because of loss of power and refrigeration.
The next phase after backup power generators run out of fuel within 5 to 30 days:
- National and regional fuel distribution systems, fuel pipelines, and pumps.
- Global or national food supply because of no ability to transport.
- Municipal water distribution systems.
- Municipal wastewater distribution systems.
- All transportation, including private and public transportation systems.
In a standard electric circuit, a voltage source—such as a battery, outlet, or any device—prompts electrical charges to travel through a wire, creating an electric current. This is the most prevalent method for generating electric currents.
However, there’s another way to produce an electric current. By altering the magnetic field within a wire coil, currents can be induced. When a current runs through the coil, the internal magnetic field shifts.
Switching off the current results in another magnetic field alteration. This fluctuating magnetic field eventually induces an electric current to flow through the wire without the need for a battery or any external voltage source.
This induced current concept renders the Sun’s activities or space weather profoundly perilous to Earth’s inhabitants. Magnetic fields that change due to these celestial phenomena can induce massive electrical currents. These currents then traverse our global electrical infrastructure, much like conventionally produced electricity.
However, the predicament lies in the intensity. Electrical currents generated by CMEs dwarf the controlled electrical outputs created by humans. This overwhelming electrical surge can lead to:
- Electrical shorts
- Blackouts and power outages
In essence, every CME poses a potential threat to Earth. The only requirement for disaster is for the CME to penetrate Earth’s atmosphere.
Coronal Mass Ejections (CMEs), vast eruptions from the Sun, have the potential to disrupt Earth’s infrastructure, economies, and life as we know it, especially when certain conditions align.
While not every CME directly endangers our planet, their threat is amplified by Earth’s extensive electrical infrastructure.
The interplay between changing magnetic fields and our global electrical systems can induce powerful currents, leading to fires, blackouts, and other calamities.
Thus, while not all CMEs inherently spell doom, their interaction with modern infrastructure makes them a concern worth monitoring closely.
- Investigation of Coronal Mass Ejections. I. Loop-type with Arcade Flare between the Fixed Legs, and Bubble-type Due to Flare Blast Waves | Publications of the Astronomical Society of Australia | Cambridge Core
- Big Think: A Giant Solar Flare Is Inevitable, and Humanity Is Completely Unprepared
- NASA/ADS: Flare-Induced Coronal Disturbances Observed with Norikura “NOGIS” Coronagraph: A CME Onset
- Rensselaer Polytechnic Institute: Introduction to Magnetism and Induced Currents
- Springer Link: Classification of CMEs Based on Their Dynamics