ARLA/CLUSTER: Fwd: Ciclo Solar 24... Será o principio?

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Segunda-Feira, 17 de Dezembro de 2007 - 13:59:54 WET

---------- Forwarded message ----------
From: Salomao Fresco <sal.fresco>
Date: 15/12/2007 22:02
Subject: Ciclo Solar 24... Será o principio?
To: ARLA <cs1rla.arla>

  Na sequência do aumento do número de manchas solares, vale a pena
questionar se o próximo ciclo Solar não estará a começar agora.

Is a New Solar Cycle Beginning?   12.14.2007


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*Dec. 14, 2007:* The solar physics community is abuzz this week. No, there
haven't been any great eruptions or solar storms. The source of the
excitement is a modest knot of magnetism that popped over the sun's eastern
limb on Dec. 11th, pictured below in a pair of images from the orbiting
Solar and Heliospheric Observatory (SOHO).

It may not look like much, but "this patch of magnetism could be a sign of
the next solar cycle," says solar physicist David Hathaway of the Marshall
Space Flight Center.

[image: see caption]

*Above:* From SOHO, a UV-wavelength image of the sun and a map showing
positive (white) and negative (black) magnetic polarities. The new
high-latitude active region is magnetically reversed, marking it as a
harbinger of a new solar cycle.

For more than a year, the sun has been experiencing a lull in activity,
marking the end of Solar Cycle 23, which peaked with many furious storms in
2000--2003. "Solar minimum is upon us," he says.

The big question now is, when will the *next* solar cycle begin?

It could be starting now.

"New solar cycles always begin with a high-latitude, reversed polarity
sunspot," explains Hathaway. "Reversed polarity " means a sunspot with
opposite magnetic polarity compared to sunspots from the previous solar
cycle. "High-latitude" refers to the sun's grid of latitude and longitude.
Old cycle spots congregate near the sun's equator. New cycle spots appear
higher, around 25 or 30 degrees latitude.

The region that appeared on Dec. 11th fits both these criteria. It is high
latitude (24 degrees N) and magnetically reversed. Just one problem: *There
is no sunspot*. So far the region is just a bright knot of magnetic fields.
If, however, these fields coalesce into a dark sunspot, scientists are ready
to announce that Solar Cycle 24 has officially begun.

*Below:* Solar Cycle 23 is coming to an end. What's next? Image credit:
NOAA/Space Weather Prediction Center.

Many forecasters believe Solar Cycle 24 will be big and intense. Peaking in
2011 or 2012, the cycle to come could have significant impacts on
telecommunications, air traffic, power grids and GPS systems. (And don't
forget the Northern Lights!) In this age of satellites and cell phones, the
next solar cycle could make itself felt as never before.

The furious storms won't start right away, however. Solar cycles usually
take a few years to build to a frenzy and Cycle 24 will be no exception. "We
still have some quiet times ahead," says Hathaway.

Meanwhile, all eyes are on a promising little active region. Will it become
the first sunspot of a new solar cycle? Stay tuned for updates from
Science  NASA.


Author: Dr. Tony Phillips <james.a.phillips> | Production
Editor: Dr. Tony Phillips <james.a.phillips> | Credit:
Science  NASA <>


Salomão Fresco

If it works... dont fix it!

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