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The sun has gone blank twice this month. This is what it means
The sun at the moment is completely blank. But don’t worry, everything’s going to be all right.
Picture: NASA
YOU may not have noticed but our sun has gone as blank as a cue ball. As in, it’s lost its spots.
According to scientists, this unsettling phenomenon is a sign we are heading for a mini ice age.
Meteorologist and renowned sun-watcher Paul Dorian raised the alarm in his latest report, which has sparked a mild panic about an impending Game of Thrones-style winter not seen since the 17th century.
“For the second time this month, the sun has gone completely blank,” Mr Dorian says.
“The blank sun is a sign that the next solar minimum is approaching and there will be an increasing number of spotless days over the next few years.
“At first, the blankness will stretch for just a few days at a time, then it’ll continue for weeks at a time, and finally it should last for months at a time when the sunspot cycle reaches its nadir. The next solar minimum phase is expected to take place around 2019 or 2020.”
If you’re confused about what a “blank” sun is, below is a picture of what it normally looks like, in all its solar flare-and-blemishes glory.
Not blank: Plenty going on here. Picture: NASASource:Supplied
Blank: A blemish-free sun indicates decreased solar activity known as a solar minimum.
Source:Supplied
According to NASA, the sun goes through a natural solar cycle approximately every 11 years. The cycle is marked by the increase and decrease of sunspots — visible as dark blemishes on the sun’s surface, or photosphere. The greatest number of sunspots in any given solar cycle is designated as “solar maximum.” The lowest number is “solar minimum”.
“During Solar Max, huge sunspots and intense solar flares are a daily occurrence. Auroras appear in Florida. Radiation storms knock out satellites. Radio blackouts frustrate CB radio as well. The last such episode took place in the years around 2000-2001,” the space agency’s website
“During solar minimum, the opposite occurs. Solar flares are almost non-existent while whole weeks go by without a single, tiny sunspot to break the monotony of the blank sun. This is what we are experiencing now.”
Given that the sun is the main driver of all weather and climate, the sinister-sounding “blankness” to which Mr Dorian refers has some experts predicting a “Maunder Minimum” phase similar to one which began in 1645 and which is referred to as the “Little Ice Age”.
The Maunder Minimum, named after solar astronomer Edward Maunder, lasted for a brutal 70 years and was so cold the Thames froze over.
A slightly less intense ice age-like period called the Dalton Minimum — after British Meteorologist John Dalton — arrived decades later and lasted from about 1790 to 1830.
“If history is any guide, it is safe to say that weak solar activity for a prolonged period of time can have a cooling impact on global temperatures in the troposphere which is the bottommost layer of Earth’s atmosphere — and where we all live,” Mr Dorian says.
Mr Dorian’s findings back research by professor Valentina Zharkova of Northumbria University, who warned that a predicted sharp decline in solar activity between 2020 and 2050 was a sign another ice age was coming.
“I am absolutely confident in our research,” Prof Zharkova said.
“It has good mathematical background and reliable data, which has been handled correctly. In fact, our results can be repeated by any researchers with the similar data available in many solar observatories, so they can derive their own evidence of upcoming Maunder Minimum in solar magnetic field and activity.”
A graph showing the top ‘sunspotless’ days since 1849. The peach columns show when relatively brief solar minimums have occurred. In contrast, the ‘Little Ice Age’ of the 17th century coincided with a 70-year solar minimum.
Source:Supplied
And there are other consequences of a sun without spots. Not least for astronauts who face the risk of having their DNA “shattered” by cosmic rays, whose potency surges during periods of solar weakness.
According to Mr Dorian, cosmic rays surge into the inner solar system “with relative ease” during periods of solar minimum.
“Solar wind decreases and sun’s magnetic field weakens during solar minimums making it easier for cosmic rays to reach the Earth,” he explains.
“This is a more dangerous time for astronauts as the increase in potent cosmic rays can easily shatter a strand of human DNA. Also, during years of lower sunspot number, the sun’s extreme ultraviolet radiation (EUV) drops and the Earth’s upper atmosphere cools and contracts.
“With sharply lower aerodynamic drag, satellites have less trouble staying in orbit — a good thing. On the other hand, space junk tends to accumulate, making the space around Earth a more dangerous place for astronauts.”
{ http://www.news.com.au/technology/science }
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