#coronalmassejection

Coronal mass ejection

A coronal mass ejection (CME) is a significant release of plasma and magnetic field from the solar corona. They often follow solar flares and are normally present during a solar prominence eruption. The plasma is released into the solar wind, and can be observed in coronagraph imagery.

Coronal mass ejections are often associated with other forms of solar activity, but a broadly accepted theoretical understanding of these relationships has not been established. CMEs most often originate from active regions on the Sun's surface, such as groupings of sunspots associated with frequent flares. Near solar maxima, the Sun produces about three CMEs every day, whereas near solar minima, there is about one CME every five days.

Coronal mass ejections release large quantities of matter and electromagnetic radiation into space above the Sun's surface, either near the corona (sometimes called a solar prominence), or farther into the planetary system, or beyond (interplanetary CME). The ejected material is a magnetized plasma consisting primarily of electrons and protons. While solar flares are very fast (being electromagnetic radiation), CMEs are relatively slow.

Coronal mass ejections are associated with enormous changes and disturbances in the coronal magnetic field. They are usually observed with a white-light coronagraph.

Impact on Earth

When the ejection is directed towards Earth and reaches it as an interplanetary CME (ICME), the shock wave of traveling mass causes a geomagnetic storm that may disrupt Earth's magnetosphere, compressing it on the day side and extending the night-side magnetic tail. When the magnetosphere reconnects on the nightside, it releases power on the order of terawatt scale, which is directed back toward Earth's upper atmosphere.

Solar energetic particles can cause particularly strong aurorae in large regions around Earth's magnetic poles. These are also known as the Northern Lights (aurora borealis) in the northern hemisphere, and the Southern Lights (aurora australis) in the southern hemisphere.

Coronal mass ejections, along with solar flares of other origin, can disrupt radio transmissions and cause damage to satellites and electrical transmission line facilities, resulting in potentially massive and long-lasting power outages.

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Image credit: Alex Conu 

Hey, did you hear about the mega-bubble that collapsed on the Sun last year? It was so huge that it triggered an explosion that was supposed to hit Earth and cause a massive geomagnetic storm. But then something weird happened. The explosion missed us by a hair and passed mostly south of our planet. We only got a glancing blow that caused some minor auroras on higher latitudes. How lucky is that?😅

Apparently, this event was captured by a satellite called GOES-16, which has an extreme ultraviolet telescope that can see the Sun’s atmosphere. The bubble was actually a giant loop of plasma and magnetic fields that rose from the Sun’s surface and then snapped back, releasing a lot of energy. This is called a coronal mass ejection (CME) and it can travel through space at millions of kilometers per hour. If it hits Earth head-on, it can disrupt our power grids, satellites, and communications. Not to mention the beautiful but potentially dangerous auroras that can appear in the sky.

But why did the CME miss us? Well, it turns out that the direction and orientation of the CME’s magnetic fields are very important. They have to match with Earth’s magnetic field in order to cause a strong interaction. In this case, they didn’t match, so the CME just slid past us without much effect. It’s like trying to connect two magnets with the wrong poles facing each other. They just repel each other.

So we dodged a bullet there, but who knows when the next big CME will come our way? The Sun is very active right now as it reaches the peak of its 11-year cycle. That means more sunspots, flares, and CMEs are likely to happen in the near future. We better hope that our planet’s magnetic shield holds up and protects us from these solar storms. Otherwise, we might be in for some serious trouble.😱

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