The Sun's Magnetic Flip and How It Will Affect Earth

The peak of the sun's solar cycle, which runs about 11-years long, is about to hit. That means that the sun's magnetic field is about to flip, completely reversing its field in about three to four months.

This solar event only happens once during the 11-year cycle, and it signals what solar physicists call the Solar Maximum, which is the period of peak activity of our nearest star. "It looks like we're no more than three to four months away from a complete field reversal," said solar physicist Todd Hoeksema of Stanford University to NASA Science. "The change will have ripple effects throughout the solar system."

Just as Earth scientists watch the Earth's poles for possible signs of climate change, solar physicists watch the sun's poles. "The sun's polar magnetic fields weaken, go to zero, and then emerge again with the opposite polarity. This is a regular part of the solar cycle." The solar field reversal has happened uncountable numbers of times in Earth's history, and has probably occurred in your lifetime before, if you're over the age of 13 - probably without you even noticing (though scientists have measured it three times in the last four decades). However, that doesn't mean that it won't affect Earth at all.

When solar magnetic field reversals happen, part of the sun's thin, slowly-rotating magnetic field - called a "current sheet," because it induces a small current (only one ten-billionth of an amp per square meter) - gets very wavy. As the current sheet undulates and as the Earth orbits around the sun, our planet dips in and out of that current sheet. Transitions from one side of the current sheet to another can cause stormy magnetic field activities.

Problematic Effects?

According to the Daily Mail, one such event in 1859, called the Solar Superstorm, was so powerful, the Northern Lights were visible as far south as Rome. Such a superstorm in modern times could muddle our telecommunications satellites and disrupt radio communication.

Cosmic ray activity can also be affected. Cosmic rays are bursts of energetic particles that can possibly affect the climate and cloudiness of Earth, and are a danger to astronauts and satellites. However, in this case, the magnetic reversal (and its accompanying wavy current sheet) is a beneficial thing: A wavy current sheet acts as a better shield against the energetic particles, deflecting them before they can penetrate near Earth.

All things considered, don't expect the apocalypse when the sun's magnetic poles flip. We've had communications technology orbiting Earth for a while now, and no previous Solar Maximum has caused catastrophic damage. We've had a climate for a while now too, and that hasn't been savaged by any previous Solar Maximum.

Beyond Earth

It's not just Earth that is affected by the solar reversal, however. The sun's magnetic field influences everything within the heliosphere - an area around the sun that "extends billions of kilometers beyond Pluto," according to NASA. The change in the field's polarity will reach all the way to Earth's Voyager probes, which are currently just on the brink of breaking out into interstellar space.

Data from Stanford University's Wilcox Solar Observatory, which studies the sun with magnetograms, shows that the sun's poles are currently out of whack with each other, as the magnetic flip ramps up. "The sun's north pole has already changed sign, while the south pole is racing to catch up," said Phil Scherrer of Stanford University to NASA Science. "Soon, however, both poles will be reversed, and the second half the solar max will be underway."

For more information on the Solar Maximum, check out NASA's ScienceCast video below.