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Thread: The sun has lost its spots: Here's what it means.

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    Administrator Ross's Avatar
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    The sun has lost its spots: Here's what it means.

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    A blemish-free sun indicates decreased solar activity known as a solar minimum.


    You may not have noticed but our sun has gone as blank as a cue ball. As in, it's lost its spots.

    Meteorologist and sun-watcher Paul Dorian's latest report said the sun had gone "completely blank" for the second time in a month.

    "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.

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    Solar flares and activity.

    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."

    There are 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."

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    Re: The sun has lost its spots: Here's what it means.

    From Wikipedia concerning the Maunder Minimum 1645-1715:

    The Maunder Minimum roughly coincided with the middle part of the Little Ice Age, during which Europe and North America experienced colder than average temperatures. Whether there is a causal relationship, however, is still controversial, as no convincing mechanism for the solar activity to produce cold temperatures has been proposed,[12] and the current best hypothesis for the cause of the Little Ice Age is that it was the result of volcanic action.

    The correlation between low sunspot activity and cold winters in England has recently been analyzed using the longest existing surface temperature record, the Central England Temperature record.[15] They emphasize that this is a regional and seasonal effect relating to European winters, and not a global effect. A potential explanation of this has been offered by observations by NASA's Solar Radiation and Climate Experiment, which suggest that solar UV output is more variable over the course of the solar cycle than scientists had previously thought.
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