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June 14, 2000
The Sun image: NASA
Meteorologists are getting better and better at tracking storms on earth and predicting where they will hit. But space storms that can disrupt communications and power systems have been harder to forecast.
Now NASA has launched a satellite, known as IMAGE, that will allow scientists to warn us about bad space weather before it strikes. With the sun expected to enter into a period of peak activity within the next 12 months, it could turn out to be quite a useful new tool.
Stormy Weather Ahead
Every 11 years or so the solar maximumthe peak of solar activityarrives, causing disturbances here on earth, 93 million miles away. During this period solar scientists will be able to see more sunspots and observe fluctuations in the suns magnetic field. But our nearest star will also expel plasma (hot, electrified gas) in the form of coronal mass ejections (CMEs). These blasts of energy disrupt the flow of the solar wind and interact with our magnetosphere, causing magnetic storms.
There is more "space junk" to be damaged than ever before. image: NASA
"The energy, once in, is then stored and explosively released, and those explosions create a lot of energetic particles that can knock out spacecraft, cause communications disruptions, and even cause electrical power grids to fuse out," says Jeffrey Hughes, professor of astronomy and director of The Center for Space Physics at Boston University.
The last solar maximum, which took place in 1989, caused a power outage in Canada that left six million people without electricity. With the next one just around the corner, theres no telling what may happen.
"The world has become much more dependent on space resources for communication," points out Patricia Reiff, chairman of the department of space physics and astronomy at Rice University, citing the prevalence of pagers, cell phones, satellite transmissions and the global positioning system (GPS).
The Wideband Imaging Camera, one of the three instruments in the IMAGE Far Ultraviolet (FUV) Imaging System (see page 2 of this story), captured this active aurora that occurred during the geomagnetic storm of June 8, 2000. The storm, which was relatively moderate (80 gamma), was triggered by a coronal mass ejection that was observed at the Sun on June 6. The auroral emissions observed are from molecular nitrogen that is excited by precipitating electrons.
If you prefer to use RealPlayer, click here. movie by S. Mende and H. Frey, Space Sciences Laboratory, University of California, Berkeley
While there were about 200 satellites in orbit during the last solar maximum, today there are more than 600. "When one of them fails, then somebody on earth is going to suffer," says Reiff. Besides power outages, disruptions can affect everything from ATM machines to TV and radio transmissions to phone lines. Solar maximums have even been connected to droughts, according to Reiff. "All of these things can hit us the way we live and in our pocketbooks," she says.
What You See Is What You Get
IMAGE, short for Imager for Magnetopause-to-Aurora Global Exploration, is the first spacecraft that will allow us to see previously invisible space storms in the earths magnetosphere the magnetic field that surrounds and protects our planet. "IMAGE is our new eyes in space," says Reiff.
Previously, scientists had to rely on data transmitted by individual spacecraft as they passed through the magnetosphere, which meant their views were very limited. But IMAGE allows them to view the earths entire magnetosphere at once. According to Reiff, these images will do for the study of space weather what radar did for meteorologists studying hurricanes. "IMAGE is going to bring a similar kind of imaging technology that will revolutionize our understanding of and predicting ability for space weather," she says.
This EUV movie shows the ionized-helium component of the plasmasphere as viewed over a four-hour period on May 24. The Earth is at the center of the images; the Sun is to the upper left. The view is toward Earths north pole.
If you prefer to use RealPlayer, click here. movie by B. Sandel and T. Forrester, Univ. of Arizona
To do that, IMAGE relies on several imaging techniques. Three neutral atom imagers record the shape and motion of the clouds of plasma that make up a magnetic storm. The far-ultraviolet imaging system collects the first-ever space images of earths proton aurora, otherwise known as the northern and southern lights. The extreme ultraviolet imager (EUV - see movie at right) captures views of the plasmasphere, beyond the upper reaches of earths ionosphere, which will let scientists know precisely when magnetic storms hit.
Then theres the radio plasma imager, which uses radio pulses to provide a three-dimensional view of the plasmosphere, somewhat like an ultrasound image of the human body. It has an antenna that extends 1,640 feet, making it the longest antenna ever used in space, longer than the height of the Empire State Building.
The first pictures, which came in two weeks ago, showed how plasma around the earth ebbed and flowed in response to solar wind. IMAGE has an open data set, meaning that its information is available to everyone. Images from each instrument are available on the Internet within 24 hours of being received.
Even though researchers knew IMAGEs capabilities and predicted what the instruments would show, seeing the results for the first time has been surprising. "And thats the real excitement of being a scientist," says Reiff. "We think we know what were going to see, but when we see it, its something new."