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Solar Explosions Could Impact Earth

08/09/2011

The National Oceanic and Atmospheric Administration (NOAA) is keeping an eye on a set of solar storms and explosions that could disrupt satellite, telecommunications and electric equipment here on Earth in the next few days. While activity had reportedly returned to somewhat normal levels when solar winds calmed the morning of Monday, August 8, another explosion at 0805 UTC on Tuesday, August 9 was three times larger than the February 15 flare, which, until now, was the most significant flare of Solar Cycle 24. 

Given the location of the activity of Tuesday’s flare, any coronal mass ejection (CMEs) from the flare would likely be directed away from Earth. As such, the Space Weather Prediction Center (SWPC) is not forecasting “significant Geomagnetic Storm activity” and the most recent storms should not affect radio amateurs. But when a CME does hit the Earth’s atmosphere -- approximately 72 hours after exploding on the Sun --  the low bands will be depressed and signals will be weaker the lower the frequency. The absorption rate will be most severe on 160 meters, less on 80 and somewhat better on 40 meters. The maximum usable frequency (MUF) -- the highest frequency by which a radio wave can propagate between given terminals by ionospheric propagation alone, independent of power -- will be lower and auroral propagation on the VHF bands is quite possible.

In 2013, solar activity levels are expected to peak with the next solar maximum within the 11-year solar activity cycle. “We now know how powerful space weather can be and how events that begin on the surface of the Sun can end up wreaking havoc here on Earth,” said SWPC Director Tom Bogdan. “This is why NOAA has a Space Weather Prediction Center -- to forecast when space weather is coming our way, so we can avoid or mitigate damages. We’re coming up to the next solar maximum, so we expect to see more of these storms coming from the Sun over the next three to five years.”

Electric and magnetic interference from solar storms blasting electrically charged particles into the Earth’s magnetic field can cause major problems on Earth. When a space weather storm is on the way, satellite operators can switch into standby mode and temporarily forgo communication between ground control and spacecraft in orbit to prevent the garbling of messages. Airlines can reroute planes that normally take fuel-saving polar routes. Along those routes, pilots depend on HF radio communications that are vulnerable to disruptions by space weather. This impact has already occurred in 2011: In February and June, airlines reported loss of HF communication near the Arctic, due to space weather. But pilots and commercial aircraft are not the only ones at risk: NOAA cautions that many systems humans use every day are vulnerable to changes in space weather, including GPS applications in mobile phones and in cars, power grids and military satellites.

People in 1859 didn’t have that advantage when a solar eruption caused a giant aurora visible as far south as the Caribbean Islands and essentially charged the air on Earth with electricity, taking out telegraph offices across the globe. According to NOAA, some telegraph operators received electric shocks and papers within offices caught fire. The interference even caused telegraph equipment to continue distributing signals once the equipment had been turned off. A 2008 report by the National Research Council predicted that a storm of similar magnitude today could cause $1 to $2 trillion in damage, globally.  -- Thanks to the National Oceanic and Atmospheric Administration, the Space Weather Prediction Center and the Solar Dynamics Observatory for some information



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