Final update, Aug. 6, 11:00 a.m. EDT - Looks like our chances for additional aurora activity are zero. Although the Boston area didn't get any nice aurorae, plenty of other folks did. The good news for skygazers is that the sun's activity cycle is just starting to ramp up. In another three years or so, we'll be at solar maximum. And then, let the light show begin!
Update, Aug. 5, 10:45 a.m. EDT - Waves 3 and 4 are "dragging their feet" and haven't yet reached Earth. Dr. Golub notes that, "unlike trains in Japan, these eruptions don't run on a clockwork schedule." Coronal mass ejections change speed as they travel through interplanetary space. (Contact your local magnetohydrodynamicist for details.) Nevertheless, Earth's magnetosphere continued to reverberate from waves 1 and 2 last night, rewarding sky watchers from Wisconsin to Norway with spectacular aurorae.
Update, Aug. 4, 12:30 p.m. EDT - The first two waves of solar particles have come and gone. Both arrived a bit earlier than expected. No further information is available on the two waves that will arrive later today. Indications are that they will produce auroral activity similar to last night. Our home base of New England was clouded out, but we've received positive reports from Michigan, Wisconsin, Denmark, and Germany. For an aurora photo gallery, visit SpaceWeather.com.
Aug. 3, 4:30 p.m. EDT - We'll have multiple opportunities for a display of the Northern Lights over the next two days. The latest word from the solar scientists is that the Sun erupted not just once, but four times. All four coronal mass ejections are headed toward Earth.
Space weather forecasts are even more challenging than regular weather forecasts. Dr. Leon Golub says a coronal mass ejection is like a hurricane: it’s large and fuzzy, and doesn’t always move at the same speed. Currently, the estimated arrival times are:
- Wednesday, Aug. 4 – 3:00 a.m. EDT
- Wednesday, Aug. 4 – 1:00 p.m. EDT (aurorae not visible in daylight)
- Wednesday, Aug. 4 – 8:00 p.m. EDT
- Thursday, Aug. 5 – 2:00 a.m. EDT
Any one of these events may or may not generate an aurora. It depends on details like magnetic field orientation. If the magnetic field in the oncoming solar plasma is directed opposite Earth’s magnetic field, the result could be spectacular aurorae. If the fields line up, the coronal mass ejection could slide past our planet with nary a ripple.
Viewing tips: No fancy equipment is needed to see the Northern Lights. You should seek a viewing location with dark skies, as far from city lights as possible. Then, look to the north. An aurora appears as a ghostly sheen of light, colored green or red, that slowly shimmers and undulates over time. An aurora can disappear within minutes or last for hours.
Watch this space for more updates as they become available.
Other Resources
Map of current auroral activity:
http://www.swpc.noaa.gov/pmap/index.html
Chart of proton flux (watch for the numbers to go up as each wave arrives):