Untitled DocumentThis is an archived version of our daily Space Weather Forecast
from Friday, November 10, 2000, in the midst of a severe solar storm.
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| RADIATION ALERT
Severe Solar Storm
A severe space weather storm began pounding Earth late Wednesday and is expected to threaten communications, satellite operations, and possibly astronauts and airline passengers -- especially pregnant women -- through Sunday. Forecasters said this could be the fourth largest solar radiation storm since 1976. It began Wednesday, November 8, at 4:50 p.m. MST (2350 UT), and has reached severe level (S4 on the NOAA Space Weather Scales).
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Update for Friday, November 10
A NOAA forecaster told SPACE.com Friday morning that the radiation levels are dropping and would gradually subside through Sunday. Fresh solar activity is expected to be at low to moderate levels through the weekend. Isolated M-class flares are possible. There is a 10 percent chance of a severe X-class flare into Saturday. There is a chance for active northern light Friday night.
What caused the current radiation storm?
The event began when a group of sunspots called 9218 kicked up an M-class solar flare from deep within the Sun. This energy interacted with the solar atmosphere, sending a stream of charged particles called protons heading toward Earth.
Wednesday's spike in radiation
This NOAA graphic shows the flux of high-energy protons near Earth beginning Nov. 7. The spike shows the beginning of the storm Wednesday afternoon. The activity is measured by the GOES 8 satellite. |
See an animation of the event
In the image, a coronal mass ejection to the right is followed by a proton barrage that overwhelms the SOHO satellite's camera.
Source: NASA/SOHO |
"The protons measured near the Earth increased 10,000 times in the matter of a few minutes," said Joseph Kunches, lead forecaster at NOAA's Space Environment Center.
The proton stream is "well connected" with Earth. Kunches explained a complicated interaction in the Sun's outwardly spiraling magnetic field lines, which extend well beyond our planet. Because the Sun rotates, these magnetic lines get wound up, similar to a sprinkler in your yard. "This activity yesterday afternoon was in a prime spot to have those protons that were accelerated just run right down that field line and go by the Earth."
NOAA forecasters said the events on the Sun also triggered a coronal mass ejection, whose energy would be expected hit Earth 2-3 days later -- Friday or Saturday -- if it were directed toward us. These CMEs, as they are called, typically trigger increases in the aurora, or northern lights. Full Aurora Forecast.
Possible effects of an S4 storm
| What happens on Earth, and when?
Large solar flares like Wednesday's S4 event affect Earth's upper atmosphere almost immediately, muddling communications and radio navigation (GPS and LORAN). Energetic particles arrive in 20 minutes to several hours, threatening the electronics of spacecraft and unprotected astronauts. Other effects arrive later, depending on the event. Electrically charged particles called plasma can arrive in 30-72 hours. This sets off geomagnetic storms, causing currents to flow in Earth's magnetosphere and particles to be energized. The currents heat the atmosphere and increase drag on satellites; they can also induce voltages and currents in electric power grids on Earth. The energetic particles also cause the northern lights. |
Danger to humans: Unavoidable radiation hazard to astronauts if they are on spacewalks; elevated radiation exposure to passengers on commercial jets at high latitudes is possible. The effect can be the equivalent of 10 chest X-rays.
An FAA scientist told SPACE.com that while he would fly today, he would advise pregnant women to consider delaying their plans until this storm subsides.
Satellite operations: May experience memory device problems and noise on imaging systems; star-tracker problems may cause orientation problems, and solar panel efficiency can be degraded.
Other systems: Blackout of high frequency radio communications through the polar regions and increased navigation errors over several days are likely. Birds and other migratory animals can also have their navigation systems affected.
How unusual is this storm?
Scientists expect only three storms of this magnitude to occur during any peak in the 11-year solar cycle. The Sun is currently in the midst of one of these peaks, known as a solar max. Read more in our Space Weather 101 section.
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| 3-Day Aurora Forecast
Geomagnetic field might increase to active or major storm levels Friday night and into Saturday, due to the coronal mass ejection discussed above. A separate coronal hole might also feed the aurora heading into the weekend. No significant increase in aurora is expected from the current severe stream of protons, however.  View aurora activity right now!
Live geomagnetic activity data
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Best bet: Friday night
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On Friday morning, NOAA space weather forecaster Christopher Balch told SPACE.com that the energy from this event began reaching Earth late Thursday -- sooner than expected -- and that there was a chance for a strong aurora display at mid-latitudes Friday night.
"But there's a lot of uncertainty," Balch said. "It seems like getting that far south is less likely (than earlier expected). If we get anything at all, it's going to be more of a high-latitude disturbance."
Either way, he said, the aurora will likely quiet down by Sunday, barring any new solar activity.
Extended Space Weather Forecast
Once the current storm passes, solar activity and the corresponding geomagnetic activity on Earth will be mostly at mild levels through November 14.
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| Solar Data
Thursday's sunspot number was 149. Thursday morning's solar wind speed was 277 kilometers per second (619,600 mph). The solar wind density Thursday is 1 protons per cubic centimeter. But this number has been all over the ballpark (as high as 52 on Wednesday) and one scientist said it may not be an accurate reading during the current solar storm. (Speed and density values are snapshots in time and change during the day. About these numbers.)
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Recent Activity
The geomagnetic field experienced minor storm levels at mid latitudes with mostly active to major storm levels at high latitudes in early November as the energy from a November 3 coronal mass ejection flew past Earth. Also, a high-speed coronal hole pumped a stream of energy Earthward into November 4.
The sunspot number on Thursday, November 2, was 213, the highest since Oct. 4.
A group of sunspots called Region 9209 produced a moderate (M-class) solar flare Sunday, Oct. 29. The shock wave from this event passed Earth with little effect on Halloween, though the solar wind jumped to more than 500 kilometers per second for a short stretch.
SOURCE FOR SOLAR/GEOMAGNETIC INFORMATION
NOAA's Space Environment Center; Geophysical Institute, Univ. of Alaska, Fairbanks; NASA/MSFC
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See the Sun right now!
Ian Law sent us this view of the northern lights from Scotland. Click to enlarge
