You’ve probably heard of or seen photos of the Aurora Borealis – a natural light show in the northern night sky. But did you know this phenomenon is actually caused by solar storms, happening on the Sun's surface 93 million miles away?
As it happens, the storms aren’t just in the business of putting on a great show. They can also interfere with GPS and satellites, and even cause major power outages.
Later this year, solar activity is expected to increase, and so will the likelihood that these storms will affect our everyday lives on Earth. Travel, communications, phone service and basic power are all vulnerable to solar storms.
So, what causes these solar storms? How do they affect us here on Earth? And what can we do to protect infrastructure and ourselves? That's the topic of today's "Just Explain It."
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Let’s start by going straight to the source: the Sun.
On the Sun’s surface, turbulent magnetic activity creates what are called sunspots. If the sunspots are powerful enough, they can cause bursts of light known as solar flares.
Sunspots and other solar activity can also release charged particles and plasma from the Sun’s surface. The ejection of these particles is known as a coronal mass ejection, or CME.
While solar flares can create some disruptions here on Earth, it’s the CMEs that cause major problems.
The charged particles of a CME typically take about three days to reach Earth. When they do, they usually bounce off the magnetic field surrounding the planet.
Here’s where the pretty lights come in. The aurora in the night sky is actually caused by those particles from the CME bouncing around in Earth’s magnetic field.
But it can turn ugly. If enough particles get trapped in the magnetic field, they can actually cause it to shake. This shaking is called a geomagnetic storm and it can wreak havoc on our electric grids.
It’s happened before. On March 13, 1989, a massive CME created a geomagnetic storm that shut down power in Quebec, Canada for 12 hours.
But the most powerful geomagnetic storm on record was the Carrington Event in 1859. It’s named for astronomer Richard Carrington who first saw the CME’s sunspots. There were worldwide reports of telegraph communications failing, with sparks exploding from machines and even catching papers on fire.
Why is this so important now? Solar activity goes in 11-year cycles. The current cycle is expected to reach its solar maximum, or peak, later this year. That means more CMEs, and more chances for those storms to impact us here on Earth.
[Related: 'Graceful Eruption' on Sun Revealed in Stunning Photo]
With our reliance on electricity, a Carrington-sized CME could be catastrophic. In a worst-case scenario, GPS, communications and power grids could be out for months or longer. One report said a major solar event could cost the country 1-2 trillion dollars in the first year alone. And it could take four-to-ten years to fully bounce back.
While this doomsday situation is unlikely, scientists and power companies monitor solar activity so steps can be taken to protect infrastructure against a CME. Because it takes about three days to get here from the Sun, there would be time to re-route or ground air travel. Some satellites could be switched to a safe mode that protects them from solar particles. And electricity providers could protect their equipment by disconnecting transformers.
The rest of us could prepare for possible blackouts. So, that generator you’ve been thinking about may not a bad idea.
Let us know. Are you going become a solar storm prepper? Or are you simply hoping for more cool photos of auroras coming out in the next year? Give us your feedback in the comments section below, or on Twitter using #JustExplainIt and #YahooNews.
- Natural Phenomena
- Nature & Environment
- solar storms