The sun is on the eve of an important event: a reversal of the magnetic field.
This phenomenon occurs approximately every eleven years and marks an important stage in the development of the economy solar cycle. The shift in polarity indicates the halfway point maximum solar energy the height of solar activity and the beginning of the shift to solar minimum.
The last time the sunEarth's magnetic field changed in late 2013. But what causes this switch in polarity, and is it dangerous? Let's take a closer look at the reversal of the Sun's magnetic field and explore what effects it could have on it Soil.
Related: How a giant sunspot unleashed solar storms that created global auroras that blinded us allTo understand the reversal of the magnetic field, it is first important to be familiar with the solar cycle. This approximately 11-year cycle of solar activity is driven by the sun's magnetic field and is indicated by the frequency and intensity of solar activity. sunspots visible on the surface. The height of solar activity during a given solar cycle is known as the solar maximum, and current estimates predict that this will occur between 1 and 2 hours late 2024 and early 2026.
But there is another very important, albeit lesser known, cycle that includes two eleven-year solar cycles. This magnetic cycle, known as the Hale cycle, lasts about 22 years, causing the Sun's magnetic field to reverse and then return to its original state. Ryan French a solar astrophysicist and writer for Space.com, told Space.com.
During solar minimum, the Sun's magnetic field is close to a dipole, with one north pole and one south pole, similar to The Earth's magnetic field. But as we get closer to solar maximum, "the Sun's magnetic field becomes more complex, with no clear separation between the north-south pole," French said. By the time solar maximum is over and solar minimum arrives, the Sun has returned to a dipole, albeit with a reversed polarity.
The coming polarity change will take place from the northern to the southern magnetic field in the Northern Hemisphere and vice versa in the Southern Hemisphere. "This will put it in a similar magnetic orientation to Earth, which also has its south-facing magnetic field in the Northern Hemisphere," French explains.
What causes the switch in polarity?
The reversal is caused by sunspots, magnetically complex regions on the Sun's surface that can produce important solar events, such as solar flares And coronal mass ejections (CMEs) - large explosions of plasma and magnetic field.
As sunspots form close to the equator, they will have an orientation that matches the old magnetic field, while sunspots that form closer to the poles will have a magnetic field that matches the incoming magnetic orientation, French said. This is called Hale's law.
"The magnetic field from active regions works its way toward the poles and eventually causes the reversal," says solar physicist Todd Hoeksema, director of the Wilcox Solar Observatory at Stanford University. previously told Space.com.
But the exact underlying cause of such a switch in polarity remains mysterious. 'That affects the whole thing [solar] cycle, and we wonder what that is," solar physicist Phil Scherrer of Stanford University previously told Space.com. "We still don't have a real stand-alone mathematical description of what's happening. And until you can model it, you don't really understand it; It's hard to really understand."
It really depends on where the magnetic field is coming from. "Will there be many sunspots? And will the sunspots contribute to the pole's magnetic field, or will they disappear locally?" said Hoeksema. "We don't know how to answer that question yet."
How quickly will the changeover take place?
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What we do know is that the change in the sun's magnetic field does not happen instantaneously. It is a gradual transition from a dipole to a complex magnetic field to an inverted dipole over the entire eleven-year solar cycle. "Basically, there is no specific 'moment' when the sun's poles flip," French said. "It's not like on Earth, where the change is measured by the migration of the North/South Pole."
It typically takes a year or two for a complete reversal, but this can vary significantly. For example, the Arctic field of Solar Cycle 24, which ended in December 2019, took almost five years to reverse, according to the National Solar Observatory.
The change in the magnetic field is so gradual that you don't even notice it when it happens. And no, as dramatic as it sounds, it is not the sign of an impending apocalypse. "The world will not end tomorrow," Scherrer said told earlier Space.com.
However, we will experience some side effects of the polarity reversal.
How does the sun's magnetic movement affect us?
There's no doubt that the sun has been incredibly active lately, firing off numerous powerful solar flares and CMEs, creating strong geomagnetic storms on Earth, which in turn have caused some solar flares. incredible aurora displays lately.
However, the increased severity of space again is not the direct cause of the polarity change. These things are more likely to occur together, Hoeksema told Space.com in 2013.
According to French, space weather is typically strongest during solar maximum, when the sun's magnetic field is also at its most complex.
One side effect of the magnetic field shift is minor but mostly beneficial: it can help protect Earth from galactic phenomena cosmic rays - high-energy subatomic particles that travel at nearly the speed of light and can damage spacecraft and harm astronauts in orbit outside Earth's protective atmosphere.
As the Sun's magnetic field shifts, the "current layer" - a vast surface radiating outwards from the Sun's equator for billions of kilometers - is created becomes very wavy creating a better barrier against cosmic radiation.
Predicting the future strengths of the solar cycle
Scientists will closely monitor the reversal of the Sun's magnetic field and see how long it takes for it to return to a dipole configuration. If that happens within the next few years, the next eleven-year cycle will be relatively active, but if the build-up is slow, the cycle will be relatively weak, like the previous Solar Cycle 24.
