Sunspot AR1476, which is so large that NASA scientists are calling it a “monster,” has rotated around the sun and is about to put Earth in its crosshairs.
Sunspot AR1476, which was first spotted by NASA’s Solar Dynamics Observatory this past weekend, is so big that it has been visible without the aid of solar telescopes. Consisting of at least four dark cores, each of which is larger than the Earth, AR1476 measures more than 60,000 miles across. The gigantic sunspot can be seen at sunrise and sunset when the light of the low-hanging sun is somewhat dimmed to human visibility. (WARNING: Never look directly at the sun with your naked eye or with unfiltered telescopes or binoculars. Special filters are required for viewing the sun directly.)
Sunspots are temporary phenomena on the photosphere of the Sun’s surface, and appear as dark spots because they are slightly cooler than surrounding areas (being roughly 3,000 to 4,500 degrees Kelvin as opposed to around 5,780 K). Sunspots form when there is intense magnetic activity on the sun, and can increase in number as the sun ramps up towards solar maximum. The next solar maximum will occur in 2013. Scientists use sunspots to measure the sun’s activity.
Thus far, sunspot AR1476 has proven to be quite active. On Thursday morning, May 10, SpaceWeather.com reported AR1476 unleashed a strong M4- or M5-class solar flare. Fortunately, the almost X-class eruption did not send a significant coronal mass ejection (CME) toward Earth, although a minor radio blackout was reported by NOAA (National Oceanic and Atmospheric Administration). Earlier in the week, AR1476 fired off a couple of M-class flares which did launch CMEs toward Earth. CMEs are massive clouds of solar plasma that travel through space at speeds of 3 million mph and higher. Along with solar flares, CMEs can disrupt radio transmissions and cause damage to satellites in space and power grid systems on Earth. CMEs can also produce dazzling displays of northern and southern lights (auroras).
Sunspot AR1476 has the potential to produce some of the strongest types of solar flares known (X-class) because it has a “beta-gamma-delta” magnetic field, which means it contains plenty of energy to produce very strong eruptions. X-class solar flares are the largest and strongest class of solar flares, and are considered major events because they can trigger planet-wide communications and power-grid disruptions and blackouts. They are also capable of producing long-lasting geomagnetic storms. M-class flares are considered to be moderate sized, and may cause brief radio blackouts and minor radiation storms. C-class flares are considered the smallest, and have the least noticeable effects on Earth. NOAA forecasters are estimating event probabilities of 75% for additional M-class flares and 20% for X-class flares during the next several days as sunspot region 1476 continues to grow in size.
In addition to AR 1476, another sunspot group, AR 1471, erupted on the sun’s surface this week as well, shooting an M1 flare towards Earth.
The sun has been surprisingly quiet during this current solar cycle (24), but may be coming into a more active period as it heads towards solar maximum in 2013. Solar storms are inevitable, and today’s modern society depends heavily on technologies that are vulnerable to the effects of intense geomagnetic storms and other solar-energetic particle events. Could there be another Carrington Event or, thanks to improved prediction systems, will we be able to take appropriate mitigation actions to prevent large-scale blackouts and damage should an intense storm occur? With AR1476 turning its aim towards Earth, we just might find out.
Article as it appears on GCN:
http://www.gcnlive.com/wp/2012/05/11/barb-adams-monster-sunspot-turns-towards-earth/
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