[ti:Solar Activity Can Affect Communication, Power on Earth]
[ar:Jim Tedder]
[al:Science In The News]
[by:www.21voa.com]
[00:00.00]Scientists who study the sun watch for sunspots -- 
[00:04.48]violent storms that can affect communications, 
[00:08.22]navigation systems and even electric power stations on Earth.
[00:13.59]One of those scientists is Alex Young 
[00:16.85]of the Goddard Space Flight Center in Greenbelt, Maryland. 
[00:21.28]Crews at Goddard are studying the Earth and our solar system for NASA, 
[00:26.76]the National Aeronautics and Space Administration. 
[00:30.20]Mr. Young recently told VOA what the space agency is learning about the sun.
[00:36.53]Sunspots are a product of huge electromagnetic storms on the sun. 
[00:43.16]Scientists on Earth are able to observe sunspots eight minutes after they happen. 
[00:50.05]That is how long it takes for the sun's light to reach us.
[00:54.14]The first electrically charged particles from a sunspot enter Earth's atmosphere 
[01:00.82]about 20 to 30 minutes after the storm happens. 
[01:04.80]These particles can harm human beings. 
[01:08.00]So before they arrive, astronauts on the International Space Station 
[01:13.52]move into special areas designed to protect them from their effects.
[01:19.06]About a day or two later, the biggest part of the storm arrives. 
[01:24.36]It is called a coronal mass ejection.
[01:28.20]"That is billions of tons of solar material that's blown away from the sun. 
[01:34.23](When) it's traveling millions of kilometers an hour, but that is relatively slow."
[01:40.56]That is Alex Young. He is the Associate Director 
[01:45.39]for Science at NASA's Heliophysics Science Division.
[01:49.77]Several civilian government agencies and the U.S. Air Force 
[01:54.82]watch weather conditions in space 24 hours a day. 
[02:00.25]NASA does so because it must protect its astronauts 
[02:05.43]and the electronic devices on its spacecraft.
[02:08.98]Scientists are also trying to understand 
[02:12.41]why the number of sunspots rises and falls at almost regular intervals every 11 years. 
[02:21.04]In other words, scientists can almost predict the amount of solar activity.
[02:27.07]"Also, sometimes the intensity is higher, 
[02:31.41]sometimes lower. For example, the current solar cycle, 
[02:35.75]as we call it, that we are in, is much lower than the previous one."
[02:39.99]Several satellites watch the sun and the environment between the sun and the earth. 
[02:45.97]Pictures and other information from the satellites tell scientists 
[02:51.40]what is happening on and near the sun.
[02:54.30]Alex Young says we have only been looking at the sun 
[02:58.38]with powerful instruments for about 30 to 40 years. 
[03:02.82]That is a very short time 
[03:05.81]compared to the four billion years that the star has been shining.
[03:10.59]I'm Jim Tedder.
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