Source:
http://edition.cnn.com/2003/TECH/spa...ast/index.html
(CNN) -- Satellites, pagers, cell phones and electrical grids could be affected Friday afternoon by a powerful stream of energized gas and particles from the sun.
The coronal mass ejection, or CME, is expected to reach Earth about 3 p.m. EDT and its effects could last 12 to 18 hours, according to space weather forecasters.
The solar stream erupted from a cluster of sunspots on the surface of the sun. The giant dark patch, known as sunspot group 10484, has grown to the size of Jupiter in recent days and has migrated across the face of the sun to a position where it now faces Earth.
The National Oceanic and Atmospheric Administration's Space Environment Center in Boulder, Colorado, warns a number of industries when there is a major release of such hot bursts of solar gases, which usually take two to four days to reach Earth. This particular storm was detected Wednesday.
In the midst of these electromagnetic events, power companies often refrain from peak uploading and downloading of power across the grid. Airlines are also alerted, because some navigation systems may be affected.
Satellites are perhaps most affected by the solar activity.
"Satellites live and breathe in space; they are very vulnerable to solar activity," said Larry Combs, NOAA space weather forecaster. "They affect our banking systems, our TVs and cell phones, all the luxuries of life."
Combs said some operators will put their satellites into a stow, or a sort of "sleep" mode, during the highest impact of the electromagnetic activity.
In the past there have been major outages and interruptions of cell phone and pager service because of electromagnetic interference with orbiting communications satellites.
In 2000, one such solar blast briefly knocked out or created steering problems for numerous orbiting spacecraft.
"Sometimes satellites can be damaged beyond repair," said Combs. But there are hundreds of satellites in space now, most with some sort of backup possible.
Closeup of Jupiter-sized sunspot group 10484
Such geomagnetic storms can disrupt power grids as well. In 1989, one knocked out the main electrical utility in Quebec, Canada, plunging millions into darkness for hours and costing billions of dollars to fix
The CMEs can also have a biological effect on humans, so space forecasters do daily briefings that might affect any crews in space. For example, it would not be a good idea to do a space walk when a solar event is predicted.
Forecasters track the CMEs from the time they leave the sun, and as the material gets closer to Earth they observe spikes in X-rays and electromagnetic emissions.
Solar activity is rated, similar to the system for hurricanes or earthquakes, on a scale of 1 to 5, with 5 as the most intense. The effects from this storm are expected to be classified 3, or moderate.
The magnetic storms can also produce spectacular nocturnal displays of the Northern lights; NASA's Space Weather Web site is predicting that auroras could be visible as far south as Oregon and Illinois.
Scientists made their first solar storm forecasts in 1964. Since then a variety of instruments, both in space and on the ground, have improved their ability to track the activity.
"But like anything in nature, sometimes they don't act like we expect them to," Combs said.