Thursday, July 05, 2012

Sun unleashes huge solar flare at the end of 11-year cycle

Our Sun may add to the fireworks as our American friends celebrate their  Independence Day

On Monday, July 2, a regiona of our Sun known as active region 1515 unleashed a solar flare aimed squarely at the Earth. This group sunspots – from which solar flares originate — has been crackling with radio and X-ray energy for days and Monday’s flare was an M5.6-class flare, just a notch down from the strongest possible.

While this isn’t all that surprising, it will have some very noticeable effects here on Earth. Our sun goes through 11-year cycles and will near the peak of cycle 24 next year. As we get closer to that peak, flares are going to get more intense. This most-recent flare was only the latest in a string, including an X-class flare which dealt our Earth’s magnetic field a glancing blow on March 7.

Our history is riddled with the effects of solar flares. Solar flares carry intense amounts of energy that can actually add electricity to our phone lines, fiber optic cables and satellites that we use for all of our modern activities. The now-famous Bastille Day event on July 14, 2000, and the X45-class Halloween flare of 2003 caused communications disruptions worldwide around the peak of the last solar cycle. Back in 1989, a flare caused 6 million people in Quebec to lose power when it overloaded transformers.

Historically, one of the largest events was the Carrington Super flare of 1859, which caused the Northern Lights to be seen as far south as Puerto Rico and disrupted telegraph lines around the world. In fact, operators on the east coast of the United States found there was enough current on the line to send telegraph messages even with their batteries disconnected.

But with an aging power infrastructure and a growing reliance on communications technology, there is now some concern as to what a powerful flare would do today. In space, solar activity can damage satellites and endanger astronauts. Passengers flying along polar routes may even experience a substantially higher dose of radiation, forcing some flights to re-route.

That’s why a fleet of international spacecraft are now monitoring the Sun as never before in human history. These include the European Space Agency’s Solar Heliospheric Observatory, the Proba-2  microsattelite, Japan’s Hinode, and NASA’s Solar Dynamics Observatory.

NASA’s Twin STEREO spacecraft also monitor the Sun from different vantage points along Earth’s orbit, giving us a full 360 degree view of the solar surface.

This solar cycle may prove to be lackluster by historic standards. Between 2008 and 2010, scientists recorded the lowest ebb of solar activity in the past century and there is some conjecture that Cycle 25 may be especially weak, following the theories of NASA solar physicist David Hathaway who supposed that the churning behaviour in the Sun’s interior is actually slowing down and the entire solar cycle may be disrupted as soon as 2022.

When this has happened in the past, cosmic ray levels have also gone  up when we’re at a solar minimum. The solar wind ebbs and more particles from beyond our solar system are able to reach the Earth. One famous, and hotly debated, extended solar lull was known as the Maunder Minimum, which stretched from 1645 to 1715. During this period, the Thames River froze, virtually no sunspots were recorded by the observers of the day and crops failed due to short growing seasons.

Unfortunately, a weak solar cycle and cooling via global dimming (albedo or reflectivity due to increased cloud cover) may be masking the effects of global warming, adding fuel to the political debate.

Whatever the case, our sun is worth keeping an eye on. If skies are clear, observers across North America above latitude 40 degree north may be in for a summer showing of the aurora borealis. This is one of nature’s finest spectacles, and requires no equipment—just a set of eyes– to watch.

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