While only polar explorers and the most barefoot sailors use the sun for manual navigation these days, we are still dependant on our parent star for satellite navigation. Image from Antarctica, ExWeb files.
2008: blank sun could mark calm before the storm in space weather forecast
Posted: Oct 14, 2008 01:58 am EDT
A Greek once claimed that all the earth's oceans are connected. He insisted that Africa can be circumnavigated and that India can be reached by sailing westward from Spain. He stated that the earth is round and he even calculated its diameter to within an error of fifty miles. The big deal? Eratosthenes proposed all this around 200 BC, or almost 2000 years before Columbus voyage.
With the current series from HET; this Columbus day we continue the focus on expedition technology - and an aspect that was equally important to Columbus as it is to us, namely, the Sun.
While only polar explorers and the most barefoot sailors use our parent star for manual navigation these days, we are just as dependant on it as Columbus was in terms of knowning our whereabouts. Team HET therefore always keeps an eye not only on high altitude-, polar- and ocean weather; but also the latest solar activity reports.
Space weather forecast
You might have noticed that there have been little interference in your satphone calls lately. That's because right now the sun is quiet. Around two years back we reached the end of the last Solar Cycle, which peaked in 2001.
Solar activity rises and falls in 11-year cycles, swinging back and forth between times of quiet and storminess. Sunspot magnetic fields reverse polarity from cycle to cycle and a tiny, magnetically backward sunspot born on July 31, 2006 marked the beginning of our current solar cycle.
Expected to be exceptionally stormy, perhaps the stormiest in decades; sunspots and solar flares will return in abundance; producing bright auroras on Earth, mess up expeditions' satellite phones and play havoc with other satellite based tech such as GPS.
Solar cycles take time to build up to fever pitch, up to several years. For now, we have enjoyed a "blank sun" - the star has sported very low activity. But today, SpaceWeather.com is reporting that a "new-cycle" sunspot belonging to Solar Cycle 24 is emerging near the sun's northeastern limb.
"This is the third time in as many weeks that a new-cycle sunspot has interrupted the year's remarkable run of blank suns," the source explains. "The accelerating pace of new-cycle sunspot production is an encouraging sign that, while solar activity remains very low, the sunspot cycle is unfolding more or less normally."
All well in satellite world; or the calm before the storm? Stay tuned...
Sunspots are planet-sized magnets created by the sun's inner magnetic dynamo. Like all magnets in the Universe, sunspots have north (N) and south (S) magnetic poles. The sunspot of July 31st, 2006, popped up at solar longitude 65o W, latitude 13o S. Sunspots in that area are normally oriented N-S. The newcomer, however, was S-N, opposite the norm. The first spot of a new solar cycle is always backwards. Solar physicists have long known that sunspot magnetic fields reverse polarity from cycle to cycle. N-S becomes S-N and vice versa.
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