Major sunspots photographed by NASA's Solar Dynamics Observatory spacecraft.
(Image Sources: NASA, Wikipedia.org, By NASA - http://www.dailymail.co.uk/sciencetech/article-2042428/Best-auroras-seen-Britain-thanks-huge-solar-flares.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=16800815)
By Glenn A. Walsh
Reporting for SpaceWatchtower
Will the Sun continue to propagate weak
solar activity, or will the Sun suddenly become much more active,
affecting the Northern Lights, radio reception, orbiting satellites,
and the power grid?
Last September, NASA and the National
Oceanic and Atmospheric Administration (NOAA) announced that a new
11-year sunspot cycle had begun on the Sun, and this cycle would
likely be as weak as the previous cycle. However, in December, a new
report issued by the National Center for Atmospheric Research (NCAR)
contradicts the September report arguing that the new solar cycle
could be one of the strongest in history!
Sunspots, which have been observed on
other stars (hence, known as star-spots) in addition to our Sun, are
complex and temporary phenomena caused by the twisting of magnetic
fields in the photosphere of the Sun. They usually come in pairs, with each having an opposite magnetic polarity. Sunspots appear as black or
gray spots on the Sun because they are cooler than the rest of the
photosphere.
But, sunspots are far from cold.
Sunspots measure +4,892 to +7,592 degrees Fahrenheit / +2,700 to
+4,200 degrees Celsius, while the rest of the Sun's photosphere
usually has a temperature around +9,932 degrees Fahrenheit / +5,500
degrees Celsius. Hence, by comparison, sunspots appear black or gray because they are cooler.
When viewed on the surface of the Sun,
sunspots appear as a black spot, known as the umbra, often surrounded
by a gray area known as the penumbra. Great care must be taken
when attempting to view sunspots, as eye-sight could be damaged if
proper precautions are not taken anytime you look directly at the
Sun. Galileo, who first used a telescope to view sunspots, was
not aware of the danger, and his eye-sight suffered as a consequence.
Many people use special filters on
telescopes to observe sunspots. These filters are safe, so
long as they are from a well-respected telescope vendor, are
specifically designed for solar observing, and are undamaged.
Further, only use solar filters that are placed over the telescope
objective (where the Sun-light enters the telescope). Solar
filters produced many years ago, that are installed at the eye-piece
of the telescope, are very dangerous and can fail, as the strength of
the magnified Sun-light cracks the filter, allowing unfiltered
Sun-light to enter a person's eye.
The best way to observe sunspots is to
project the image of the Sun from a telescope onto a projection
screen, where people can safely see the sunspots on the projection
screen. From 1941 to 1991, this method was used to show the public
sunspots, using the rather unique 10-inch Siderostat-type Refractor
Telescope, at Pittsburgh's original Buhl Planetarium and Institute of
Popular Science (a.k.a. Buhl Science Center).
Scientists now believe that Solar Cycle
24 ended in December of 2019. It takes several months to confirm the
ending of a solar cycle, hence scientists did not announce this until
September. Solar magnetic North and South Poles change or "flip" magnetic polarity as a solar cycle changes.
Solar Cycle 24 peaked in April of 2014,
after beginning in 2011. While, on average, a sunspot cycle runs for
11 years, Solar Cycle 24 was also one of the shortest, running for
less than 9 years.
Only a total of 116 sunspots were
counted during that short time period, making Solar Cycle 24 one of
the weakest in memory. Further, in 2019 there were more than 281 days
(77 per-cent of the year) when the side of the Sun facing Earth had
no sunspots at all! It has been more than a century since we have
observed that long of a period without sunspots.
In September, NASA and NOAA predicted
that the new Solar Cycle 25 would only have a total of 115 sunspots.
However, NCAR scientists claim solar and sunspot activity could come
roaring back during the new cycle, with sunspots totaling between 210
and 260! They note that the last time there was a 9-year cycle, in
the 1950s, was followed by Solar Cycle 19, one of the strongest in
the 20th century.
In a mathematical analysis, looking at
270 years of sunspot records (since 1755), NCAR determined that the
shorter one solar cycle is, the greater the chance that the following
solar cycle will be much stronger. This study, “Overlapping
Magnetic Activity Cycles and the Sunspot Number: Forecasting Sunspot
Cycle 25 Amplitude,” was published in the 2020 November 24 issue of
the peer-reviewed journal Solar
Physics.
If
the new NCAR hypothesis turns-out to be true, this would be strong
evidence supporting the NCAR theory that the 11-year sunspot cycle is
produced by overlapping 22-year magnetic cycles on the Sun. From a
series of papers published over the last decade, NCAR has been
promoting this new theory. They believe that a better understanding
of this 22-year Hale Cycle could lead to a more accurate prediction of the
timing and nature of sunspot cycles.
NCAR
Deputy Director and solar physicist Scott McIntosh told NCAR and UCAR
News:
“Scientists
have struggled to predict both the length and the strength of sunspot
cycles because we lack a fundamental understanding of the mechanism
that drives the cycle. If our forecast proves correct, we will have
evidence that our framework for understanding the sun’s internal
magnetic machine is on the right path.”
Study
co-author Bob Leamon, a researcher at the University of Maryland
Baltimore County adds:
“When
we look back over the 270-year long observational record of
terminator events, we see that the longer the time between
terminators, the weaker the next cycle. And, conversely, the shorter
the time between terminators, the stronger the next solar cycle is.”
In his previous works, Dr. McIntosh has found that magnetic field bands, which wrap around the Sun as part of the extended 22-year solar cycle, migrate from high latitudes toward the solar equator over a 20-year or-so period. As these magnetic field bands cross the mid-latitudes, often sunspots emerge. When these magnetic field bands, which have opposite polarities in the Northern and Southern Hemispheres, meet and destroy each other at the equator, a new magnetic cycle and a new sunspot cycle begin.
The
National Science Foundation, NCAR's sponsor, and NASA's Living With a
Star Program supported this new research.
Internet Links to Additional Information ---
Sunspots: Link >>> https://en.wikipedia.org/wiki/Sunspot
Solar Phenomena: Link >>> https://en.wikipedia.org/wiki/Solar_phenomena
Earth's Sun: Link >>> https://en.wikipedia.org/wiki/Sun
Additional Information Regarding NCAR Hypothesis:
Link 1 >>> https://earthsky.org/space/sunspot-cycle-25-among-strongest-on-record-says-ncar
Link 2 >>> https://www.universetoday.com/149468/will-solar-cycle-25-dazzle-or-fizzle-in-2021/
NASA: Link >>> https://www.nasa.gov/
NOAA: Link >>> https://www.noaa.gov/
NCAR: Link >>> https://ncar.ucar.edu/
Related Blog-Posts ---
"Strong Solar Flare Seen, Although Approaching Sunspot Minimum." Sat., 2017 July 15.
"Largest Sunspot in 24 Years Returns for 2nd Month." Sun., 2014 Nov. 23.
Source:
Glenn A. Walsh Reporting for SpaceWatchtower,
a project of Friends
of the Zeiss.
Wednesday, 2021 February 10.
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Formerly
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original Buhl Planetarium & Institute of Popular Science (a.k.a.
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from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library
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Expected landing site on Mars for NASA's Perseverance Rover, including the Ingenuity Helicopter Drone. Landing sites of some previous NASA missions to Mars are also shown.
