Interesting facts about solar flares that are hotter than the Sun's core

Solar flares are powerful natural events, but what are they exactly?
Christopher McFadden
Solar flares.cokada/iStock

With solar flares featuring heavily in the news of late, we thought it might be a good idea to get the low down on these incredible astronomical events. 

If you have never heard the term before or would like to know more, then read on to find out more. 

What is a solar flare?

A solar flare is a powerful radiation flash caused by the release of magnetic energy, such as from a sunspot. They are some of the greatest explosive events in our Solar System and are both intensely fascinating as well as unimaginably energetic events.

Interesting facts about solar flares that are hotter than the Sun's core
Source: IngaNielsen/iStock

They can persist for a few minutes to several hours and are seen as bright spots on the Sun. A solar flare is often visible by the photons (or light) it emits at nearly all wavelengths. X-rays and optical light are the main methods used to track flares. Particles (such as electrons, protons, and heavier particles) are also accelerated by flares.

What is a solar storm?

The term "solar storm" refers to a large-scale magnetic eruption, often causing a coronal mass ejection and associated solar flare, accelerating charged particles in the solar atmosphere to very high velocities.

You probably picture the Sun as a constant source of bright light, but it is actually a massive ball of molten gases in constant flux (a state of change). When the Sun releases massive energy bursts in the form of solar flares and coronal mass ejections (CME), solar storms result. About three million miles per hour of electrical charges and magnetic fields can be sent toward the Earth during these events. 

When a solar storm hits Earth, it frequently causes parts of the atmosphere to flash brilliantly with "northern lights" displays that can be seen in regions close to the Arctic Circle. Satellites and many forms of electronic communication can be affected by solar storms as well.

These events generally start out as huge explosions on the surface of the Sun. These eruptions, known as solar flares, have an explosive force comparable to billions of nuclear bombs.

solar flares closeup
Source: vitacopS/iStock

Large streams of charged plasma that are released during solar flares typically travel at speeds of several million miles per hour. Coronal mass ejections (CMEs) are the name given to these streams. Satellites and electrical power networks may be affected by geomagnetic storms brought on by CMEs that strike the Earth.

A CME caused by a very intense solar flare, for instance, cut out radio communications in China in February 2011. According to some analysts, a significant solar storm could possibly produce more economic damage than the worst hurricane, by a factor of over 20.

Researchers that focus on solar storms have found that solar flare frequency appears to be governed by an 11-year solar cycle. The number of solar storms can range from several per day during solar maximum to less than one every week during solar minimum. Scientists anticipate that solar storm activity will peak in 2024 as a result of the Sun's current activity cycle.

What causes a solar flare?

There is a lot of activity on the Sun's surface. It contains electrically charged gases that produce strong magnetic fields in some regions.

cmes the sun
Source: Pitris/iStock

The surface of the Sun is a very active place. Electrically charged gases generate powerful magnetic fields. These magnetic fields are continually being stretched, twisted, and tangled by the rotating gases of the Sun. The surface of the Sun experiences a great deal of solar activity as a result of this motion.

While the Sun's surface can be quite active, it can also be a little quieter at other times. As the solar cycle progresses, so does the level of solar activity. Because solar activity may have an impact on Earth, astronomers constantly track it.

Typically, astronomers will keep track of something called sunspots. But what are these?

Dark spots on the surface of the Sun are called sunspots. Because they are cooler than other areas of the Sun's surface, they seem dark. Even so, a sunspot is still quite hot—somewhere around 6,500 degrees Fahrenheit!

Why do sunspots have a chilly temperature? It's because they develop in locations with extremely strong magnetic fields. Because of how powerful these magnetic fields are, part of the heat from the Sun's interior is prevented from reaching the surface of the Sun.

Near sunspots, the magnetic field lines frequently rearrange, cross, and tangle. A solar flare, which is a quick explosion of energy, may result from this. A lot of radiation is sent into space during solar flares. Radiation from a solar flare that is very strong may obstruct radio communications on Earth.

what are solar flares
Source: LV4260/iStock

Coronal mass ejections (CME for short) can occasionally accompany solar flares. Large solar radiation and particle bubbles are known as CMEs. The CMEs can explode into space at extremely high speeds when the Sun's magnetic field lines suddenly reorganize.

What are the different types of solar storms?

As we've previously explained, a solar storm is a term used to describe eruptions of mass and energy from the solar surface, which can emanate outward across the heliosphere, potentially affecting the entire Solar System.

When the Sun generates powerful energy bursts like solar flares and coronal mass ejections, solar storms result. High-speed electrical charges and magnetic fields are rapidly sent toward the Earth by these occurrences.

The production of strong auroras such as the "northern lights," which are visible in the areas near the Arctic Circle, is one of the impacts of a solar storm affecting Earth. Disruption of satellites and other electronic communication systems is one of the negative effects of solar storms.

types of solar flares
A solar flare captured by NASA's Solar Dynamics Observatory. Source: NASA

Solar activity associated with space weather is sometimes divided into four main components:

  • Solar flares: A solar flare is an abrupt increase in brightness in an area on the Sun that is typically seen close to its surface or near a sunspot or group of sunspots. A coronal mass ejection frequently, but not always, occurs together with strong flares. In the context of total solar irradiation, often known as the "solar constant," even the strongest flares are hardly noticeable.
  • Coronal Mass Ejection (CME): These may be associated with solar flares or may occur on their own. They involve a sudden and violent release of pockets of gas and magnetic fields. A large CME can contain a billion tons of matter, accelerated to several million miles per hour in a huge explosion. Large CMEs can also lead to geomagnetic storms, a major disturbance of Earth's magnetosphere that occurs when there is a large exchange of energy from the solar wind into the space surrounding Earth. Geomagnetic storms result from variations in the solar wind that produces major changes in the currents, plasmas, and fields in Earth's magnetosphere. 
  • Solar Storm: A solar storm occurs when the Sun emits huge bursts of energy in the form of solar flares and coronal mass ejections. A brief disruption of the Earth's magnetosphere is brought on by an interaction between the magnetic fields of the Sun and the Earth.
  • Solar Particle Events: A solar particle event, also known as a solar proton event (SPE), or prompt proton event, occurs when particles (mostly protons) emitted by the Sun are accelerated either by coronal mass ejection shocks in interplanetary space or by flares that occur close to the Sun during the event.

How dangerous are solar storms?

When the Sun is in an active phase of its 11-year cycle, observers looking through telescopes with specialized solar filters and taking pictures of the Sun can see dark sunspots dotting its surface. Solar flares, some of the most explosive events in our solar system, and brief but spectacular and powerful bursts of radiation that persist for a few minutes to many hours on the surface of the Sun will be detected by space observatories.

solar model
NASA's Solar Dynamics Observatory captured this image of a solar flare on March 30, 2022. Source: NASA

Strong CMEs are also occasionally discharged into the interplanetary medium from the Sun. These enormous bubbles of gas and magnetic fields can contain up to a billion tons of charged particles and have velocities of up to several million miles per hour. This solar matter flows out into space and occasionally collides with Earth.

Is that hazardous? Do we need to worry if one ever goes off in our direction?

On the surface of the Earth, solar storms pose little threat to people. Although the thought of these storms is terrifying, they cannot hurt us as long as we are on the surface of the Earth, where we are shielded from the direct impact of charged particles by the atmosphere and the terrestrial magnetic field. The charged particles rotate around magnetic field lines and propagate toward the poles or are trapped in the radiation belts. Similarly, the magnetic field also offers protection from CMEs. 

What threat does a solar storm pose in outer space? Extremely high-energy particles, such as those transported by CMEs, can expose people and technology to high levels of radiation and strong radio bursts. They would pose a threat to unprotected astronauts, such as those going to the moon, as well as to any unprotected technology they relied on.

Significant doses may be lethal.

On the surface of the Earth, solar storms and their impacts pose no direct threat to humans or animal life. We are shielded from the effects of solar flares by the atmosphere and magnetosphere of the Earth.

solar flares spots
Source: NASA/Wikimedia Commons

Solar storms, however, can pose a significant threat to our technologies. The Earth's magnetic field is momentarily perturbed when a CME hits the atmosphere, potentially leading to geomagnetic storms. 

Strong, polarized radio bursts can affect GPS navigation systems. If this is disrupted, even for 15 minutes, the typical duration of a flare of a radio burst, it can cause technological failure in many devices. Charged particles might also damage or possibly destroy satellites in orbit if they are not protected enough and are able to interfere with navigation and communication systems.

They may have an impact on electricity grids and have been known to cause complete local or even regional blackouts. One prime example occurred on March 13th, 1989. During this event, a CME which had occurred three days earlier knocked off the electricity in areas of the northeastern United States and Québec. Millions of people suffered from a loss of electricity that lasted for around nine hours.  

However, solar storms that are much more potent than the ones that led to the 1989 blackout in the northeastern United States and Québec are feasible. On August the 28th, 1859, for example, the greatest solar outburst ever recorded occurred. It is sometimes referred to as the "1859 Solar Superstorm" or the "Carrington Event" after amateur astronomer Richard C. Carrington observed and documented it.

Instead of the normal three or four days, the coronal mass ejection (CME) that accompanied it reached Earth in about 17 hours. There was the biggest geomagnetic storm ever observed.

During the event, aurora were spotted all around the world. Europe and North America both experienced a telegraph system failure.

What would happen if a solar storm of such force struck today? And is it likely that a solar storm this strong will happen again during our lifetimes?

Nobody is certain of the answers to these questions.

But, scientists are working hard to understand solar storms and their effects. For instance, researchers have hypothesized that a solar storm was to blame for a power outage that occurred in New Zealand in 2001.

This finding, if accurate, is especially significant because New Zealand is not located at a high latitude (like Québec, for instance). It shares the same middle latitude as much of the United States. According to this 2012 study, solar storm effects can extend into the more populated middle latitudes.

Scientists continuously observe the Sun from space and from the surface of the Earth, for instance, at the Space Weather Prediction Center. They observe solar storms that could potentially have an impact on Earth. After all, the solar storm would need to occur on the side of the Sun that faces Earth in order to have an impact on us here on Earth.

next carrington will be devastating
Source: samirabdala/iStock

CMEs normally take several days to reach Earth, making it feasible for satellites to quickly turn off their systems and stay safe while a large CME is approaching. Similarly, Earth-based power grids can be rearranged with enough notice to add an additional grounding, or otherwise be prepared.

Do we face a threat from a particularly powerful solar storm, potentially comparable to the "Carrington Event" in size? Some think we might.

In order to develop systems and procedures to help survive such strong effects from solar ejections, governments and scientists are starting to pay more attention to this subject. However, as of yet, our modern interconnected world is woefully ill-prepared for such an event. 

What are some interesting facts about solar flares?

We've already covered a lot of ground above, but if you want some fast-paced, hard-hitting facts about these incredible natural phenomena, then please read on. 

1. The fastest solar ejections can travel to Earth in a matter of days

solar storms
Solar flares headed towards Earth. Source: solarseven/iStock

Coronal mass ejections (CMEs), enormous outpourings of energy and material that can move at speeds of around 620 miles per second (1,000 kilometers per second), are sometimes associated with solar flares. Where emitted, these CMEs can travel the distance between the Sun and Earth within a matter of days.

2. Compared to volcanoes, solar flares emit ten million times more energy

solar flares power
Artist's rendition of solar flares. Source: -Vitan-/iStock

Believe it or not, a solar flare is far more powerful than a volcanic eruption. A solar flare, triggered by magnetic fields, can expel billions of tons of charged particles in a matter of minutes.

"The energy emitted by a solar flare is more than a million times greater than the energy from a volcanic explosion on Earth! Although solar flares can be visible in white light, they are often more readily noticed via their bright X-ray and ultraviolet emissions," explained the UCAR Center of Science Education

Not only that, but according to NASA, solar flares can release as much energy as a billion megatons of TNT. In contrast, the Hiroshima bomb's atomic yield was somewhere around 13,000 tons of TNT.

3. There can be more than 20 solar flares every day at peak periods

The Sun can produce around 100 solar flares each week when it reaches solar maximum. This is the point in its 11-year cycle when solar activity is at its most intense. 

Thankfully, most of these are not pointed in Earth's direction. 

4. Solar flares are hotter than the Sun's core

Coronal mass ejection. Source: ESA/NASA/Soho

The temperature inside a solar flare typically reaches 10 or 20 million degrees Kelvin and can be as high as 100 million degrees Kelvin. In comparison, the Sun's core typically reaches temperatures of about 27 million degrees F (15 million degrees C). 

5. They can wreak havoc on electrical systems and gadgets

cmes elecs

The Hydro-Quebec power grid in Canada was severely damaged in March 1989 by a massive CME that was among the largest ever recorded. Such events show us just how powerful the Sun, and cosmos in general, can be. 

When these coronal mass ejections hit the Earth, they can trigger mild to severe geomagnetic storms that can damage GPS satellites and power infrastructures.

Other examples have occurred in more modern times too. For example. China's radio communications were hampered by a CME that an X-class solar flare, the highest classification, created in February 2011.

According to a National Academy of Sciences research from 2008, a significant solar storm might result in twenty times the economic damage that Hurricane Katrina did.

6. Depending on how quickly they move, they become more or less deadly

sun surface
Source: NASA

Scientists may be able to assess if high-energy particles can cause damage on Earth by measuring their speed during intense solar storms.

According to Joseph Kunches, a scientist at the Space Weather Prediction Center, "generally speaking, if they're slower, they'll deposit all of the energy into your body because they're not fast enough to fly right through," 

7. Predicting them is very tricky

image of sun
Source: manjik/iStock

The time it takes for solar flare radiation to reach Earth from the Sun is just over 8 minutes. As a result, we don't have much time to react to these eruptions.

Although it can be difficult to predict space weather, we have gotten better at it over the past few decades.

Powerful flares rarely give us much warning before impacting and can have a substantial impact on spacecraft, satellites, and ground-based systems. NASA, NOAA, and the U.S. Air Force Weather Agency (AFWA) are among the many agencies keeping a careful eye on the Sun and closely monitoring it for strong flares and related magnetic storms. These groups can alert technological industries that are susceptible to solar flare activity so that the proper safety measures can be taken.

"We can't ignore space weather, but we can take appropriate measures to protect ourselves," NASA says

Solar flares are usually not a cause for concern. There are no so-called "killing flares," and while solar flares can potentially dramatically disrupt technology, they lack the energy to cause long-term harm to Earth.

"Even at their worst, the sun's flares are not physically capable of destroying Earth," NASA says. 

8. The current solar activity peak should be around 2025

As we are now in Solar Cycle 25, the 25th cycle to occur since regular record-keeping began with Solar Cycle 1 in 1755. Solar Cycle 24 lasted 11 years, an average length, and had the 4th-smallest intensity since regular record-keeping began with Solar Cycle 1. It was also the weakest cycle in 100 years. 

Solar Cycle 25, which began in 2019, is also forecast to be a weak cycle. Solar maximum is expected in July 2025, with a peak of 115 sunspots.

There are various open-source places to monitor the Sun's current activity, like SpaceWeatherLive.

They record the most recent 24 hours of solar X-ray data from the main GOES-16 satellite and display such activity in helpful graphs along with the percentage chance of different types of solar flares, so users can find out if there is a solar flare today and stay up to date with the most recent space weather findings.

9. Superflares are unlikely from our Sun, but not impossible

It may come as a surprise that red dwarf stars, which are typically considerably fainter and cooler than the Sun, can produce flares with substantially higher total energies because of changes in their interior structures. Could our Sun ever produce one too? 

"Superflares are produced by stars that have very strong magnetic fields and therefore are associated with more violent activity than our Sun," Stephanie Yardley, a space weather specialist at University College London's Mullard Space Science Laboratory in the U.K., told Live Science.

"However, superflares do happen on stars that are similar to our Sun. Evidence from studying carbon isotopes found in tree rings suggests that superflares may have been produced by our Sun thousands of years ago and so could occur in the future — but these events are extremely rare," he added.

And that, Solar activity addicts, is your lot for today. 

Solar flares, and their associated outpouring from the Sun, are dramatic events but are completely natural and nothing to lose sleep over. While large ones have occurred over time, they do not present any serious threat to you physically. 

Our electrical grids and electrical equipment, however, cannot say the same! Sometimes it pays to be made of flesh and bone!

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