Solar Flares – Can They Harm Humans? Effects of Solar Flares on Humans

Table of Contents

Carrington Event

Imagine this: it is a brisk September fall in Colorado, 1859. You are a gold miner, working deep in the mines resting in a warm tent, hiding from the Rocky Mountain weather. Suddenly – a magnificent glow appears outside your tent, brightening the sky despite it being the middle of the night. It was the aurora borealis, in locations where the “Northern Lights” never occurs. A similar story comes from Australian gold miners, where the sky filled with floating green and purple waves in the sky. How could this have happened?

Example of aurora borealis in the Arctic
Example of aurora borealis in the Arctic, Credit: Bjørkli

On September 1-2 of 1859, one of the largest solar storms ever recorded occurred, the Carrington Event. The appearance of the Northern lights around the world sparked images of the apocalypse. But as science and astronomy advanced, the Carrington Event and other solar activity has become well understood.  Most of these phenomena are caused by the Sun, with the most typical activity being solar flares. The Carrington Event seems to be an oddity, but our Earth is bombarded with solar flares and energy from the Sun all the time. Most of the time, the Earth can defend itself from the Sun using its own magnetic fields and atmosphere because the solar flares are very small. But what happens if another solar storm like the Carrington Event occurs in modern times? Could it impact our infrastructure? Our lives?

What are Solar Flares?

The Sun is a body of gas and plasma that is full of particles and atoms that are zipping past each other, going almost at the speed of light. These particles can be magnetic, which can create big magnetic domains in and on the surface of the Sun. These magnets can be huge and travel fast, twisting and tangling and fighting the other magnets that are formed.

Example of sunspots. Even though this is a singular picture, sunspots are mobile and move around the surface of the Sun
Example of sunspots. Even though this is a singular picture, sunspots are mobile and move around the surface of the Sun, Credit: Wikimedia/NASA Goddard Space Flight Center

A familiar sight can appear:- sunspots! It is strange to think that the bright yellow Sun produces dark spots on the surface. Sunspots are areas of intense magnetic activity, usually found in pairs of opposite magnetic polarity. These sunspots are a leading cause of the creation of solar flares. When the system reaches a level of instability, magnetic energy is converted into motion to decrease the total energy. The result is the Sun spitting out a huge number of particles at extreme speeds which are solar flares! The largest of these explosions are known as coronal mass ejections.

Example of lots of solar activity, ranging from small solar flares to coronal mass ejections
Example of lots of solar activity, ranging from small solar flares to coronal mass ejections, Credit:

Classifying Solar Activity

Speaking of powerful flares, how do we characterize the strength of flares? There are satellites that detect the X-rays coming from the Sun, and based on the power flux of these X-rays we define five types of solar flares:- A, B, C, M and X. Solar Flares A through C are relatively weak, with M-Flares meaning “moderate” and X-Flares being “eXtreme.” The coronal mass ejections discussed earlier are associated with M and X flares. That is when damage on the Earth can occur!


These flares are electromagnetic energy, the same energy that powers the internet, telephones, TVs, and the display from which you are reading this article. Typically, these energies do not interfere with another, for example; your phone is not ruining the performance of your computer. However, the electromagnetic energy of M and X flares can be very powerful! They can cause the aurora borealis to appear around the equator if they are powerful enough. There have also been instances of solar flares causing radio blackouts, or even electrical blackouts like one that occurred in Canada in 1989.


So, could solar flares directly set the world on fire? Not really. But let’s consider all the electronics around us. Potentially, a strong solar flare could cause blackouts like the ones in Canada. If communications and the power grids go offline, electricity could be cut off. Calling 911 would not work. Heat and cooling systems could fail, which would potentially cause harm during cold winters or hot summers. While solar flares cannot directly harm us, the fallout from a very large flare could cause problems.

Earth’s Magnetic Defense

Lucky for us, Earth comes with defenses! The Earth is full of magnetic liquid metal, which effectively makes Earth one gigantic magnet! This creates a magnetic shield around the Earth, which deflects most of the solar flares and activity. It is like trying to attach the south end of one magnet to the south end of another magnet, the two will simply repel and deflect each other. The same goes with most solar flares. The Sun sends flares towards Earth, they get deflected, and we remain out of harm’s way.

The Earth’s magnetic field deflecting solar storms
The Earth’s magnetic field deflecting solar storms, Credit: Wikimedia/Dennis Gallagher
Simulation of how the Earth is a big magnet
Simulation of how the Earth is a big magnet, Credit: Wikimedia/DMY

Observing and Predicting

In addition to Earth’s natural defense, we have the technology to predict and prepare for upcoming solar flares. Light from the Sun takes roughly 9 minutes to reach Earth, so we have some time to prepare for solar activity. We rely much more on satellites and telescopes to monitor the Sun than in the past. The solar cycle helps predict when sunspots, and therefore solar flare activity will rise. 

Example of satellite that can detect solar activity
Example of satellite that can detect solar activity, Credit:

If instruments pick up an increase in solar magnetic activity, there can be ample time to prepare. As stated before, our electronic infrastructure could be at risk. But with enough time, we can prepare our power grid, hospitals, electronics, and such for the impending electromagnetic storm. This can be as easy as adding insulation to gear, preparing batteries, or preparing for potential blackouts. This type of preparation is already done all over the world for hurricanes, tornados, and other bad weather. Solar flares are just space weather. With our ability to predict any outbursts, we will remain well protected.


Aurora Borealis: Also known as northern lights, or polar lights. They are magnetic disturbances in the atmosphere, causing green, blue, and purple lights that look like curtains or spirals.


Particles: A very small piece of matter, either atomic or molecular in size.


Magnetic Domain: Region of material where the magnetic direction is the same. For example, the entire north pole or entire south pole of a typical bar magnet.


Magnetic Polarity: The pole of a magnet, either “north” or “south”


Coronal Mass Ejection: A very large release of plasma, particles, and magnetic field from the Sun that is larger than a typical solar flare.


Solar Cycle: It is a predictable cycle of the Sun’s maximum and minimum activity in ejecting solar flares, coronal loops, etc. It typically lasts eleven years.

Flesch Kincaid Grade Level: 8.6


Flesch Kincaid Reading Ease: 61.6

  1. Sten F. Odenwald, James L. Green. “Bracing the Satellite Infrastructure for a Solar Superstorm.” Scientific American, 6 Dec. 2022,
  2. Herbert, Count Frank (8 October 1909). “The Great Aurora of 1859”The Daily News. Perth, WA, AU. p. 9. Retrieved 1 April2018.
  3. “Press release 990610.” 6 Dec. 2022,
  5. “Solar Flares (Radio Blackouts) | NOAA / NWS Space Weather Prediction Center.” 6 Dec. 2022,

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