Space weather: sunspots, flares and coronal mass ejections

(ORDO NEWS) — Although the Sun is at a distance of 149 million km from the Earth, it actively influences our planet.

We see sunlight and feel its warmth. However, these are far from the only results of the influence of a star comrade. There is also a constant flow of particles in the form of the solar wind, unpredictable solar flares, coronal mass ejections. All of them fall under the definition of “space weather”.

Spots on the Sun

When studying the surface of the Sun, small dark areas can be seen on it. They vary in size and location. As a rule, these spots are concentrated in areas above and below the equator. They are formed as a result of the interaction of plasma on the surface of the Sun with a magnetic field.

Sunspots are areas on the Sun that are much cooler than other areas. The temperature in these areas reaches 3,527 degrees Celsius, which is almost 1,727 degrees less than in the rest of the Sun.

However, don’t let the numbers fool you. If we had the opportunity to contemplate one sunspot in the night sky, it would shine 10 times brighter than the full moon.

Compared to the Sun, which has a diameter of 1,392 million kilometers, sunspots may appear small in size. As a rule, these areas occupy less than 4% of the visible disk of the Sun.

They are commensurate with the diameter of Neptune, the smallest of the gas planets. However, the lifespan of sunspots, regardless of location, does not exceed a few weeks.

The solar cycle, which refers to the cycle of solar activity, lasts 11 years. The last solar cycle began in January 2008 and reached its peak in 2013. Despite the low level of solar activity, scientists observed the largest sunspot in history in November 2014. It was comparable to Jupiter.

Solar Flares

Intense magnetic fields in sunspot areas also lead to explosions known as solar flares. In this case, energy is released outside with a force exceeding the energy release of millions of hydrogen bombs.

The temperature of the outer part of the solar atmosphere, known as the corona, at the time of solar flares, as a rule, reaches several million K.

When solar flares pass the corona, they heat the gas to 10-20 million K, sometimes this figure reaches one hundred million K. According to NASA , the energy that is released in a solar flare is “equivalent to the energy released when a million 100-megaton hydrogen bombs explode simultaneously.”

The largest solar flares have a significant impact on the Earth. They can cause long-term radiation storms in the upper atmosphere and cause radio communications to be interrupted. Medium flares can also cause brief outages in polar regions and occasional minor radiation storms.

Coronal mass ejections

During solar flares, the magnetic energy that accumulates in active regions on the Sun is mostly realized in the form of electromagnetic radiation. During coronal mass ejections, it is used to accelerate masses of matter in the solar crust.

Like solar flares, coronal mass ejections increase radiation in the Earth’s outer atmosphere, affecting astronauts and radio signals.

However, unlike flares, they also bring charged particles of matter that interact with the field surrounding our planet. The results of such an interaction can vary depending on the size, speed and magnetic strength of these particles.


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