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Vocapedia > Space > Solar system > Suns, Solar systems > Solar system > Sun

 

 

 

 

3D Solar System Simulator        Video        Alejandro Anghillantte        13 January 2015

YouTube

https://www.youtube.com/watch?v=y0gUKuxy6F0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

To Scale: The Solar System        16 September 2015

 

 

 

 

To Scale: The Solar System        16 september 2015

 

On a dry lakebed in Nevada,

a group of friends build the first scale model

of the solar system with complete planetary orbits:

a true illustration of our place in the universe.

 

A film by Wylie Overstreet and Alex Gorosh

 

YouTube

https://www.youtube.com/watch?t=60&v=zR3Igc3Rhfg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NASA

http://solarsystem.nasa.gov/multimedia/gallery/PIA03149.jpg

added 26 July 2007

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A stylized view of the solar system.

 

Photograph: Mopic/Alamy

 

Pluto: Nasa probe set for fly-past of frozen ‘dwarf planet’

G

Saturday 4 July 2015    10.00 BST

http://www.theguardian.com/science/2015/jul/04/nasa-probe-new-horizons-pluto-charon

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Major features of the Solar System

(not to scale; from left to right):

Pluto,

Neptune,

Uranus,

Saturn,

Jupiter,

the asteroid belt,

the Sun,

Mercury,

Venus,

Earth and its Moon,

and Mars.

 

A comet is also seen on the left.

http://upload.wikimedia.org/wikipedia/commons/c/c2/Solar_sys.jpg

http://en.wikipedia.org/wiki/Image:Solar_sys.jpg

 

NASA

Harman Smith and Laura Generosa (nee Berwin),

graphic artists and contractors to NASA's Jet Propulsion Laboratory.

Wikipedia > Solar system

http://en.wikipedia.org/wiki/Solar_System

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

http://www.ioncmaste.ca/homepage/resources/web_resources/CSA_Astro9/files/html/module4/module4.html

added 24.4.2005

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Raining Fire        NYT        4 February 2015

 

 

 

 

Raining Fire        Video        Out There | The New York Times        4 February 2015

 

Though it is sedate in comparison with other stars,

our sun is a volatile neighbor,

a thermonuclear furnace fueling spectacular storms

that send high-energy particles and radiation far out into space.

 

Produced by:

Jason Drakeford, Jonathan Corum and Dennis Overbye

Read the story here: http://nyti.ms/16AqrnT

Watch more videos at: http://nytimes.com/video

 

YouTube

https://www.youtube.com/watch?v=gmV49H555_8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

sun        UK

 

https://www.theguardian.com/science/2021/oct/14/
what-will-happen-after-the-sun-dies-serendipitous-discovery-gives-clues

 

https://www.theguardian.com/science/2020/jul/01/
ten-years-of-the-sun-in-one-hour-nasa-releases-mesmerising-space-film

 

http://www.guardian.co.uk/science/2011/feb/06/
first-panoramic-view-sun

 

 

 

 

 

 

 

sun        USA

 

https://www.nytimes.com/topic/subject/sun  

https://cosmicopia.gsfc.nasa.gov/

 

 

https://www.npr.org/2021/12/15/
1064532565/nasa-spacecraft-sun-atmosphere-parker-solar-probe

 

 

 

 

https://www.npr.org/2020/07/16/
892064722/solar-orbiter-probe-snaps-closest-photos-ever-taken-of-the-sun-revealing-tiny-fl

 

https://www.nytimes.com/2020/04/28/
science/alien-asteroids-orbits.html

 

https://www.nytimes.com/2020/04/30/
science/sun-magnetic-storms.html

 

https://www.npr.org/2020/02/07/
802700157/polar-express-new-spacecraft-will-explore-elusive-parts-of-the-sun

 

 

 

 

https://www.npr.org/2019/12/04/
784761596/probe-gets-close-to-the-sun-finds-rogue-plasma-waves-and-flipping-magnetic-field

 

 

 

 

https://www.nytimes.com/video/science/
100000006012333/nasa-parker-solar-probe.html

 

https://www.npr.org/2018/08/09/
637133541/nasa-braves-the-heat-to-get-up-close-and-personal-with-our-sun

 

 

 

 

https://www.theguardian.com/science/audio/2017/jun/11/
solar-spacecraft-two-missions-to-the-sun-science-weekly-podcast

 

http://www.npr.org/sections/thetwo-way/2017/05/31/
530743287/nasa-plans-to-launch-a-probe-next-year-to-touch-the-sun

 

 

 

 

http://www.npr.org/sections/thetwo-way/2016/05/08/
477246099/mercury-will-cross-in-front-of-the-sun-in-a-rare-event-heres-how-to-watch

 

http://www.npr.org/sections/13.7/2016/04/06/
473238503/when-the-sun-brings-darkness-and-chaos

 

 

 

 

http://www.nytimes.com/2015/05/03/
books/review/beyond-our-future-in-space-by-chris-impey.html

 

 

 

 

http://www.npr.org/blogs/thetwo-way/2014/02/14/
277058739/1-in-4-americans-think-the-sun-goes-around-the-earth-survey-says

 

 

 

 

http://www.nytimes.com/2011/06/17/
opinion/17baker.html

 

 

 

 

 

 

 

the Sun's corona

 

 

 

 

 

 

 

the Sun's atmosphere > solar flares        UK / USA

 

https://www.theguardian.com/science/2020/jul/01/
ten-years-of-the-sun-in-one-hour-nasa-releases-mesmerising-space-film

 

http://www.guardian.co.uk/science/2011/feb/17/
solar-flares-northern-lights-uk

 

http://www.guardian.co.uk/science/gallery/2007/dec/07/
spaceexploration.sciencenews?picture=331491247

 

 

 

 

 

 

 

spots        USA

 

http://www.nytimes.com/2009/07/21/
science/space/21sunspot.html

 

http://dotearth.blogs.nytimes.com/2008/10/03/
climate-and-the-spotless-sun/

http://www.nytimes.com/2008/10/03/
science/space/03sun.html

 

 

 

 

solar

 

 

 

 

solar cycle        USA

http://www.nytimes.com/2006/03/07/
science/space/07solar.html

 

 

 

 

solar storm        UK

http://www.theguardian.com/science/2015/mar/18/
solar-storm-delivers-spectacular-aurora-displays-and-pictures

 

http://www.guardian.co.uk/science/interactive/2012/mar/08/
how-solar-storms-work-interactive

 

 

 

 

solar storm        USA

http://www.npr.org/2016/11/18/
499576593/new-weather-satellite-provides-forecasts-for-the-final-frontier

 

 

 

 

Boston Globe > Big Picture > summer / winter solstice        2011

http://www.boston.com/bigpicture/2011/06/
here_comes_the_sun.html

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NASA/ESA probe > Solar Orbiter        USA

 

https://www.theguardian.com/science/2020/jul/01/
ten-years-of-the-sun-in-one-hour-nasa-releases-mesmerising-space-film

 

https://www.npr.org/2020/02/07/
802700157/polar-express-new-spacecraft-will-explore-elusive-parts-of-the-sun

 

 

 

 

 

 

 

NASA's Parker Solar Probe        UK/ USA

 

https://www.npr.org/2021/12/15/
1064532565/nasa-spacecraft-sun-atmosphere-parker-solar-probe

 

https://www.npr.org/2019/12/04/
784761596/probe-gets-close-to-the-sun-finds-rogue-plasma-waves-and-flipping-magnetic-field

 

https://www.theguardian.com/science/2018/aug/10/
mission-to-touch-the-sun-nasa-to-launch-parker-solar-probe

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NASA Solar Dynamics Observatory: The 'Variable Sun' Mission

http://science.nasa.gov/science-news/science-at-nasa/2010/05feb_sdo/ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

solar activity        UK

https://www.theguardian.com/environment/2007/jul/11/
climatechange.climatechange1

 

 

 

 

Nasa's SDO spacecraft studies the sun        2010

 

Nasa's Solar Dynamics Observatory

has produced stunning images

of flaring sunspots

at temperatures of 50,000C

 

NASA Solar Dynamics Observatory:

The 'Variable Sun' Mission

http://www.guardian.co.uk/world/video/2010/apr/22/
news-science-astronomy-nasa-sun

http://science.nasa.gov/science-news/science-at-nasa/2010/05feb_sdo/

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Meet the moons:

planetary satellites in pictures        UK         Tuesday 18 March 2014

 

On Monday the Open University

launched a free online course

introducing the rich diversity of moons

in the solar system.

 

Led by David Rothery,

professor of planetary geosciences

at the university,

the course will explore

the fundamental processes

that have shaped moons,

the relationship between

our moon and the Earth,

and the chances of finding life.

 

There will be video,

audio and interactive elements,

and contributions from moon experts

from all over the world

http://www.theguardian.com/science/gallery/2014/mar/18/
moons-planetary-satellites-solar-system-pictures
 

 

 

 

 

Boston Globe > Big Picture

Around the Solar System        USA        September 15, 2010

http://www.boston.com/bigpicture/2010/09/
around_the_solar_system.html

 

 

 

 

the outer reaches of the solar system

 

 

 

 

search for life beyond the solar system        UK

http://www.guardian.co.uk/science/2010/feb/03/
ground-based-telescopes-extraterrestrial-life

 

 

 

 

New solar system looks much like home        UK        August 2010

 

The newly discovered solar system

may contain

the largest number of planets

ever found orbiting another star

http://www.guardian.co.uk/science/2010/aug/25/
new-solar-system-hd-10180

 

 

 

 

object > 2018 VG18

https://www.nytimes.com/2018/12/17/
science/farout-most-distant-solar-system.html

 

 

 

 

solar astronomer > John A. Eddy        USA

http://www.nytimes.com/2009/06/18/us/
18eddy.html

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NASA > solar system > planets        UK / USA

 

https://pds.jpl.nasa.gov/planets/

 

 

https://www.nytimes.com/interactive/2020/
science/exploring-the-solar-system.html - July 30, 2020

 

https://www.theguardian.com/science/2020/jun/28/
beyond-pluto-the-hunt-for-our-solar-system-new-ninth-planet

 

http://www.npr.org/sections/thetwo-way/2016/01/20/
463087037/hints-of-a-hidden-distant-planet-in-our-solar-system

 

 

 

 

 

 

 

 Mercury

 

the innermost planet in our own solar system

 

https://www.npr.org/2021/12/02/
1060612038/astronomers-find-a-new-planet-thats-mostly-made-of-iron

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Scientists Spot First Alien Space Rock In Our Solar System        2017

http://www.npr.org/sections/thetwo-way/2017/10/26/
560278537/scientists-spot-first-alien-space-rock-in-our-solar-system

 

 

 

 

NASA > solar system simulator

https://space.jpl.nasa.gov/

 

 

 

 

National Geographic > virtual solar system

https://www.nationalgeographic.com/science/topic/
our-solar-system 

 

 

 

 

NASA > solar system exploration        USA

https://solarsystem.nasa.gov/ 

 

 

 

 

capture particles of the solar wind        UK

http://www.theguardian.com/science/2000/aug/09/
spaceexploration.comment

 

 

 

solar explosion

 

 

 

 

solar energy

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

http://www.nytimes.com/imagepages/2009/07/20/science/21sunspot.3.ready.html

 

Is the Sun Missing Its Spots?        NYT        21 July 2009

http://www.nytimes.com/2009/07/21/science/space/21sunspot.html

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Corpus of news articles

 

Solar system > Suns, Solar systems >

 

Solar system > Sun

 

 

 

How’s the Weather?

 

June 16, 2011

The New York Times

By MADHULIKA GUHATHAKURTA

and DANIEL N. BAKER

 

LATELY, the Sun has been behaving a bit strangely. In 2008 and 2009, it showed the least surface activity in nearly a century. Solar flare activity stopped cold and weeks and months went by without any sunspots, or areas of intense magnetism. Quiet spells are normal for the Sun, but researchers alive today had never seen anything like that two-year hibernation.

Now that the Sun is approaching the peak of its magnetic cycle, when solar storms — blasts of electrically charged magnetic clouds — are most likely to occur, no one can predict how it will behave. Will solar activity continue to be sluggish, or will solar storms rage with renewed vigor?

Luckily, policy makers are paying attention to space weather. Late last month, President Obama and the British prime minister David Cameron announced that the United States and Britain will work together to create “a fully operational global space weather warning system.” And just last week, the United Nations pledged to upgrade its space weather forecasts.

But most people have never heard of space weather, which is a problem, because both high and low solar activity have serious effects on life on Earth.

Modern society depends on a variety of technologies that are susceptible to the extremes of space weather. Spectacular explosions on the Sun’s surface produce solar storms of intense magnetism and radiation. These events can disrupt the operation of power grids, railway signaling, magnetic surveying and drilling for oil and gas. Magnetic storms also heat the upper atmosphere, changing its density and composition and disrupting radio communications and GPS units. The storms’ charged particles can be a hazard to the health of astronauts and passengers on high altitude flights.

Severe storms in 1989 and 2003 caused blackouts in Canada and Sweden. In 1859, a solar super storm sparked fires in telegraph offices. Such storms are predicted every century or so, and perhaps we’re overdue. According to a 2008 National Academies report, a once-in-a-century solar storm could cause the financial damage of 20 Hurricane Katrinas.

A quiet Sun causes its own problems. During the two-year quiet spell, our upper atmosphere, normally heated and inflated by the Sun’s extreme ultraviolet radiation, cooled off and shrank. This altered the propagation of GPS signals and slowed the rate of decay of space debris in low Earth orbit. In addition, the cosmic rays that are normally pushed out to the fringes of the solar system by solar explosions instead surged around Earth, threatening astronauts and satellites with unusually high levels of radiation.

The more we know about solar activity, the better we can protect ourselves. The Sun is surrounded by a fleet of spacecraft that can see sunspots forming, flares crackling and a solar storm about 30 minutes before it hits Earth. NASA and the National Science Foundation have also developed sophisticated models to predict where solar storms will go once they leave the Sun, akin to National Weather Service programs that track hurricanes and tornadoes on Earth. Thanks to these sentries, it is increasingly difficult for the Sun to take us by surprise.

If alerted, Internet server hubs, telecommunications centers and financial institutions can prepare for disruptions and power plant operators can disconnect transformers.

But what good are space weather alerts if people don’t understand them and won’t react to them? Consider the following: If anyone should be familiar with the risks of space weather, it’s a pilot. During solar storms, transpolar flights are routinely diverted because the storms can disrupt the planes’ communications equipment. And yet a space weather forecaster we know at the National Oceanic and Atmospheric Administration often tells a story of a conversation he had with a pilot:

Pilot: “What do you do for a living?”

Forecaster: “I forecast space weather.”

Pilot: “Really? What’s that?”

The point of the story is to highlight how far the scientific community and the government have to go to raise awareness about space weather and its effects.

With the sun waking up, trans-Atlantic cooperation comes at just the right time. Let us hope it is only the beginning of a worldwide effort to forecast and understand space weather.

 

Madhulika Guhathakurta is a solar physicist at NASA.

Daniel N. Baker is the director of the Laboratory
for Atmospheric and Space Physics at the University
of Colorado.

These views are their own.

How’s the Weather?,
NYT,
16.6.2011,
http://www.nytimes.com/2011/06/17/opinion/17baker.html

 

 

 

 

 

Is the Sun Missing Its Spots?

 

July 21, 2009

The New York Times

By KENNETH CHANG

 

The Sun is still blank (mostly).

Ever since Samuel Heinrich Schwabe, a German astronomer, first noted in 1843 that sunspots burgeon and wane over a roughly 11-year cycle, scientists have carefully watched the Sun’s activity. In the latest lull, the Sun should have reached its calmest, least pockmarked state last fall.

Indeed, last year marked the blankest year of the Sun in the last half-century — 266 days with not a single sunspot visible from Earth. Then, in the first four months of 2009, the Sun became even more blank, the pace of sunspots slowing more.

“It’s been as dead as a doornail,” David Hathaway, a solar physicist at NASA’s Marshall Space Flight Center in Huntsville, Ala., said a couple of months ago.

The Sun perked up in June and July, with a sizeable clump of 20 sunspots earlier this month.

Now it is blank again, consistent with expectations that this solar cycle will be smaller and calmer, and the maximum of activity, expected to arrive in May 2013 will not be all that maximum.

For operators of satellites and power grids, that is good news. The same roiling magnetic fields that generate sunspot blotches also accelerate a devastating rain of particles that can overload and wreck electronic equipment in orbit or on Earth.

A panel of 12 scientists assembled by the National Oceanic and Atmospheric Administration now predicts that the May 2013 peak will average 90 sunspots during that month. That would make it the weakest solar maximum since 1928, which peaked at 78 sunspots. During an average solar maximum, the Sun is covered with an average of 120 sunspots.

But the panel’s consensus “was not a unanimous decision,” said Douglas A. Biesecker, chairman of the panel. One member still believed the cycle would roar to life while others thought the maximum would peter out at only 70.

Among some global warming skeptics, there is speculation that the Sun may be on the verge of falling into an extended slumber similar to the so-called Maunder Minimum, several sunspot-scarce decades during the 17th and 18th centuries that coincided with an extended chilly period.

Most solar physicists do not think anything that odd is going on with the Sun. With the recent burst of sunspots, “I don’t see we’re going into that,” Dr. Hathaway said last week.

Still, something like the Dalton Minimum — two solar cycles in the early 1800s that peaked at about an average of 50 sunspots — lies in the realm of the possible, Dr. Hathaway said. (The minimums are named after scientists who helped identify them: Edward W. Maunder and John Dalton.)

With better telescopes on the ground and a fleet of Sun-watching spacecraft, solar scientists know a lot more about the Sun than ever before. But they do not understand everything. Solar dynamo models, which seek to capture the dynamics of the magnetic field, cannot yet explain many basic questions, not even why the solar cycles average 11 years in length.

Predicting the solar cycle is, in many ways, much like predicting the stock market. A full understanding of the forces driving solar dynamics is far out of reach, so scientists look to key indicators that correlate with future events and create models based on those.

For example, in 2006, Dr. Hathaway looked at the magnetic fields in the polar regions of the Sun, and they were strong. During past cycles, strong polar fields at minimum grew into strong fields all over the Sun at maximum and a bounty of sunspots. Because the previous cycle had been longer than average, Dr. Hathaway thought the next one would be shorter and thus solar minimum was imminent. He predicted the new solar cycle would be a ferocious one.

Instead, the new cycle did not arrive as quickly as Dr. Hathaway anticipated, and the polar field weakened. His revised prediction is for a smaller-than-average maximum. Last November, it looked like the new cycle was finally getting started, with the new cycle sunspots in the middle latitudes outnumbering the old sunspots of the dying cycle that are closer to the equator.

After a minimum, solar activity usually takes off quickly, but instead the Sun returned to slumber. “There was a long lull of several months of virtually no activity, which had me worried,” Dr. Hathaway said.

The idea that solar cycles are related to climate is hard to fit with the actual change in energy output from the sun. From solar maximum to solar minimum, the Sun’s energy output drops a minuscule 0.1 percent.

But the overlap of the Maunder Minimum with the Little Ice Age, when Europe experienced unusually cold weather, suggests that the solar cycle could have more subtle influences on climate.

One possibility proposed a decade ago by Henrik Svensmark and other scientists at the Danish National Space Center in Copenhagen looks to high-energy interstellar particles known as cosmic rays. When cosmic rays slam into the atmosphere, they break apart air molecules into ions and electrons, which causes water and sulfuric acid in the air to stick together in tiny droplets. These droplets are seeds that can grow into clouds, and clouds reflect sunlight, potentially lowering temperatures.

The Sun, the Danish scientists say, influences how many cosmic rays impinge on the atmosphere and thus the number of clouds. When the Sun is frenetic, the solar wind of charged particles it spews out increases. That expands the cocoon of magnetic fields around the solar system, deflecting some of the cosmic rays.

But, according to the hypothesis, when the sunspots and solar winds die down, the magnetic cocoon contracts, more cosmic rays reach Earth, more clouds form, less sunlight reaches the ground, and temperatures cool.

“I think it’s an important effect,” Dr. Svensmark said, although he agrees that carbon dioxide is a greenhouse gas that has certainly contributed to recent warming.

Dr. Svensmark and his colleagues found a correlation between the rate of incoming cosmic rays and the coverage of low-level clouds between 1984 and 2002. They have also found that cosmic ray levels, reflected in concentrations of various isotopes, correlate well with climate extending back thousands of years.

But other scientists found no such pattern with higher clouds, and some other observations seem inconsistent with the hypothesis.

Terry Sloan, a cosmic ray expert at the University of Lancaster in England, said if the idea were true, one would expect the cloud-generation effect to be greatest in the polar regions where the Earth’s magnetic field tends to funnel cosmic rays.

“You’d expect clouds to be modulated in the same way,” Dr. Sloan said. “We can’t find any such behavior.”

Still, “I would think there could well be some effect,” he said, but he thought the effect was probably small. Dr. Sloan’s findings indicate that the cosmic rays could at most account for 20 percent of the warming of recent years.

Even without cosmic rays, however, a 0.1 percent change in the Sun’s energy output is enough to set off El Niño- and La Niña-like events that can influence weather around the world, according to new research led by the National Center for Atmospheric Research in Boulder, Colo.

Climate modeling showed that over the largely cloud-free areas of the Pacific Ocean, the extra heating over several years warms the water, increasing evaporation. That intensifies the tropical storms and trade winds in the eastern Pacific, and the result is cooler-than-normal waters, as in a La Niña event, the scientists reported this month in the Journal of Climate.

In a year or two, the cool water pattern evolves into a pool of El Niño-like warm water, the scientists said.

New instruments should provide more information for scientists to work with. A 1.7-meter telescope at the Big Bear Solar Observatory in Southern California is up and running, and one of its first photographs shows “a string of pearls,” each about 50 miles across.

“At that scale, they can only be the fundamental fibril structure of the Sun’s magnetic field,” said Philip R. Goode, director of the solar observatory. Other telescopes may have caught hints of these tiny structures, he said, but “never so many in a row and not so clearly resolved.”

Sun-watching spacecraft cannot match the acuity of ground-based telescopes, but they can see wavelengths that are blocked by the atmosphere — and there are never any clouds in the way. The National Aeronautics and Space Administration’s newest sun-watching spacecraft, the Solar Dynamics Observatory, which is scheduled for launching this fall, will carry an instrument that will essentially be able to take sonograms that deduce the convection flows generating the magnetic fields.

That could help explain why strong magnetic fields sometimes coalesce into sunspots and why sometimes the strong fields remain disorganized without forming spots. The mechanics of how solar storms erupt out of a sunspot are also not fully understood.

A quiet cycle is no guarantee no cataclysmic solar storms will occur. The largest storm ever observed occurred in 1859, during a solar cycle similar to what is predicted.

Back then, it scrambled telegraph wires. Today, it could knock out an expanse of the power grid from Maine south to Georgia and west to Illinois. Ten percent of the orbiting satellites would be disabled. A study by the National Academy of Sciences calculated the damage would exceed a trillion dollars.

But no one can quite explain the current behavior or reliably predict the future.

“We still don’t quite understand this beast,” Dr. Hathaway said. “The theories we had for how the sunspot cycle works have major problems.”

    Is the Sun Missing Its Spots?, NYT, 21.7.2009,
    http://www.nytimes.com/2009/07/21/science/space/21sunspot.html

 

 

 

 

 

Sunspots Are Fewest Since 1954,

but Significance Is Unclear

 

October 3, 2008
The New York Times
By KENNETH CHANG

 

The Sun has been strangely unblemished this year. On more than 200 days so far this year, no sunspots were spotted. That makes the Sun blanker this year than in any year since 1954, when it was spotless for 241 days.

The Sun goes through a regular 11-year cycle, and it is now emerging from the quietest part of the cycle, or solar minimum. But even for this phase it has been unusually quiet, with little roiling of the magnetic fields that induce sunspots.

“It’s starting with a murmur,” said David H. Hathaway, a solar physicist at NASA’s Marshall Space Flight Center in Huntsville, Ala.

As of Thursday, the 276th day of the year, the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center in Boulder, Colo., had counted 205 days without a sunspot.

In another sign of solar quiescence, scientists reported last month that the solar wind, a rush of charged particles continually spewed from the Sun at a million miles an hour, had diminished to its lowest level in 50 years.

Scientists are not sure why this minimum has been especially minimal, and the episode is even playing into the global warming debate. Some wonder if this could be the start of an extended period of solar indolence that would more than offset the warming effect of human-made carbon dioxide emissions. From the middle of the 17th century to the early 18th, a period known as the Maunder Minimum, sunspots were extremely rare, and the reduced activity coincided with lower temperatures in what is known as the Little Ice Age.

Compared to the Maunder Minimum, the current pace of sunspots “makes it look like we’re having a feast, not a famine,” Dr. Hathaway said.

Scientists expect that sunspot activity will pick up in the coming months, but exactly what will happen next is open to debate. Dr. Hathaway had predicted two years ago, based on the Sun’s behavior near the end of the last cycle, that the maximum this time would be ferocious.

“I’m getting worried about that prediction now,” he said. “Normally, big cycles start early, and by doing that, they cut short the previous cycle. This one hasn’t done that.”

But many of the other competing predictions — more than 50 over all — pointed to a quieter-than-average cycle. “They do kind of go all over the map,” said Douglas Biesecker, a physicist at the Space Weather Prediction Center who led an international panel that reviewed predictions.

The solar wind is another piece of the puzzle. David J. McComas of the Southwest Research Institute in San Antonio and one of the researchers who analyzed data from the Ulysses Sun-watching spacecraft, said that the strength of the solar wind seemed to be in a long-term decline. The pressure exerted by the solar wind particles during the current minimum is about a quarter weaker than during the last solar minimum, Dr. McComas said.

Dr. McComas said scientists were still trying to figure out how all the data fits together.

“There are a number of researchers who predict the next solar cycle,” he said. “There are also a number of investment counselors who predict the future of the stock market.”

Sunspots Are Fewest Since 1954, but Significance Is Unclear,
NYT,
3.10.2008,
https://www.nytimes.com/2008/10/03/
science/space/03sun.html 

 

 

 

 

 

 

 

 

 

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