Showing posts with label sun. Show all posts
Showing posts with label sun. Show all posts

Thursday, May 28, 2009

New Solar Cycle Prediction: Fewer Sunspots, But Not Necessarily Less Activity

This is an image of the sun from NASA's twin STEREO satellites. Credit: NASA

From Physorg.:

PhysOrg.com) -- An international panel of experts has released a new prediction for the next solar cycle, stating that Solar Cycle 24 will peak in May 2013 with a below-average number of sunspots. Led by the National Oceanic and Atmospheric Administration (NOAA) and sponsored by NASA, the panel includes a dozen members from nine different government and academic institutions. Their forecast sets the stage for at least another year of mostly quiet conditions before solar activity resumes in earnest.

"If our prediction is correct, Solar Cycle 24 will have a peak sunspot number of 90, the lowest of any cycle since 1928 when Solar Cycle 16 peaked at 78," says panel chairman Doug Biesecker of the NOAA Space Weather Prediction Center, Boulder, Colo.

Read more ....

Wednesday, May 13, 2009

Changes In The Sun Are Not Causing Global Warming, New Study Shows

With the U.S. Congress beginning to consider regulations on greenhouse gases, a troubling hypothesis about how the sun may impact global warming is finally laid to rest. (Credit: iStockphoto)

From Science Daily:

ScienceDaily (May 12, 2009) — With the U.S. Congress beginning to consider regulations on greenhouse gases, a troubling hypothesis about how the sun may impact global warming is finally laid to rest.

Carnegie Mellon University's Peter Adams along with Jeff Pierce from Dalhousie University in Halifax, Canada, have developed a model to test a controversial hypothesis that says changes in the sun are causing global warming.

The hypothesis they tested was that increased solar activity reduces cloudiness by changing cosmic rays. So, when clouds decrease, more sunlight is let in, causing the earth to warm. Some climate change skeptics have tried to use this hypothesis to suggest that greenhouse gases may not be the global warming culprits that most scientists agree they are.

Read more ....

Sunday, May 10, 2009

Solar Cycle Will Be Weakest Since 1928, Forecasters Say

The sun is thought to have reached the lowest point in its activity in December 2008, but the new solar cycle has gotten off to a slow start. This week, however, two active regions (bright regions in upper-left corner) - whose knotty magnetic fields often coincide with eruptions and flares - appeared on the far side of the sun. One of NASA's twin STEREO probes snapped this image on Thursday (Image: NASA/Goddard Space Flight Center)

From New Scientist:

The sun's new solar cycle, which is thought to have begun in December 2008, will be the weakest since 1928. That is the nearly unanimous prediction of a panel of international experts, some of whom maintain that the sun will be more active than normal.

But even a mildly active sun could still generate its fair share of extreme storms that could knock out power grids and space satellites.

Solar activity waxes and wanes every 11 years. Cycles can vary widely in intensity, and there is no foolproof way to predict how the sun will behave in any given cycle.

Read more ....

Monday, May 4, 2009

The Missing Sunspots: Is This The Big Chill?

The disappearance of sunspots happens every few years, but this time it's gone on far longer than anyone expected - and there is no sign of the Sun waking up. AFP

From The Independent:

Scientists are baffled by what they’re seeing on the Sun’s surface – nothing at all. And this lack of activity could have a major impact on global warming. David Whitehouse investigates

Could the Sun play a greater role in recent climate change than has been believed? Climatologists had dismissed the idea and some solar scientists have been reticent about it because of its connections with those who those who deny climate change. But now the speculation has grown louder because of what is happening to our Sun. No living scientist has seen it behave this way. There are no sunspots.

Read more ....

Wednesday, April 22, 2009

'Quiet Sun' Baffling Astronomers

Sunspots could be seen by the Soho telescope in 2001 (l), but not this year (r)

From The BBC:

The Sun is the dimmest it has been for nearly a century.

There are no sunspots, very few solar flares - and our nearest star is the quietest it has been for a very long time.

The observations are baffling astronomers, who are due to study new pictures of the Sun, taken from space, at the UK National Astronomy Meeting.

The Sun normally undergoes an 11-year cycle of activity. At its peak, it has a tumultuous boiling atmosphere that spits out flares and planet-sized chunks of super-hot gas. This is followed by a calmer period.

Last year, it was expected that it would have been hotting up after a quiet spell. But instead it hit a 50-year year low in solar wind pressure, a 55-year low in radio emissions, and a 100-year low in sunspot activity.

Read more ....

Wednesday, April 1, 2009

NASA Headline: Deep Solar Minimum

Above: The sunspot cycle from 1995 to the present. The jagged curve traces actual sunspot counts. Smooth curves are fits to the data and one forecaster’s predictions of future activity. Credit: David Hathaway, NASA/MSFC. [more]

From Watts Up With That?

The sunspot cycle is behaving a little like the stock market. Just when you think it has hit bottom, it goes even lower.

2008 was a bear. There were no sunspots observed on 266 of the year’s 366 days (73%). To find a year with more blank suns, you have to go all the way back to 1913, which had 311 spotless days: plot. Prompted by these numbers, some observers suggested that the solar cycle had hit bottom in 2008.

Maybe not. Sunspot counts for 2009 have dropped even lower. As of March 31st, there were no sunspots on 78 of the year’s 90 days (87%).

Read more ....

Sunday, March 29, 2009

Solar Activity And Climate Change: New Sun-Watching Satellite To Monitor Sunlight Fluctuations

During periods of peak activity (front three images) sunspots, solar flares and coronal mass ejections are more common, and the sun emits slightly more energy than during periods of low activity (back images). The amount of energy that strikes Earth's atmosphere -- called total solar irradiance (TSI) -- fluctuates by about 0.1 percent over the course of the sun's 11-year cycle, even though the soft X-ray wavelengths shown in this image vary by much greater amounts. (Credit: Steele Hill, SOHO, NASA/ESA)

From Science Daily:

ScienceDaily (Mar. 29, 2009) — During the Maunder Minimum, a period of diminished solar activity between 1645 and 1715, sunspots were rare on the face of the sun, sometimes disappearing entirely for months to years. At the same time, Earth experienced a bitter cold period known as the "Little Ice Age."

Were the events connected? Scientists cannot say for sure, but it's quite likely. Slowdowns in solar activity -- evidenced by reductions in sunspot numbers -- are known to coincide with decreases in the amount of energy discharged by the sun. During the Little Ice Age, though, few would have thought to track total solar irradiance (TSI), the amount of solar energy striking Earth's upper atmosphere. In fact, the scientific instrument needed to make such measurements -- a spaceborne radiometer -- was still three centuries into the future.

Read more ....

Tuesday, March 17, 2009

Scientists Aim To Replicate The Sun

NASA's STEREO (Ahead) spacecraft observed this visually stunning prominence eruption on the Sun in the 304 angstrom wavelength of extreme UV light. Prominences are relatively cool clouds of gas suspended above the sun and controlled by magnetic forces.

From UPI:

LIVERMORE, Calif., March 15 (UPI) -- Scientists in California say they're trying to replicate the power of the sun by firing laser beams at a tiny pellet of hydrogen.

Physicists at the National Ignition Facility in Livermore say the nuclear fusion experiments may offer the world a clean source of energy
, The Times of London reported Sunday.

The hydrogen pellet will be hit with 192 laser beams capable of generating 500 trillion watts -- 1,000 times the power of the U.S. national grid, said the scientists.

Read more ....

Thursday, January 29, 2009

What's Happening To The Sun?

The First Cycle 24 Sunspot: NOAA

From Popular Science:

Could its unusual behavior herald a new ice age?

For about 50 years from roughly 1650 to 1700, the Sun took a break from its typical sunspot activity. That phase of solar rest coincided with what we now refer to as "The Little Ice Age" -- a period of cooling on the Earth that resulted in bitterly cold winters, particularly in Europe and North America. Scientists attribute the Little Ice Age to two main causes: increased volcanic activity and reduced solar activity.

Could it happen again? And are we headed there now?

Read more ....

Thursday, January 22, 2009

Did You Know A Solar Flare Can Make Your Toilet Stop Working?

Auroras over Blair, Nebraska, during a geomagnetic storm in May 2005. Photo credit: Mike Hollingshead/Spaceweather.com.

From NASA:

That's the surprising conclusion of a NASA-funded study by the National Academy of Sciences entitled Severe Space Weather Events—Understanding Societal and Economic Impacts. In the 132-page report, experts detailed what might happen to our modern, high-tech society in the event of a "super solar flare" followed by an extreme geomagnetic storm. They found that almost nothing is immune from space weather—not even the water in your bathroom.

The problem begins with the electric power grid. "Electric power is modern society's cornerstone technology on which virtually all other infrastructures and services depend," the report notes. Yet it is particularly vulnerable to bad space weather. Ground currents induced during geomagnetic storms can actually melt the copper windings of transformers at the heart of many power distribution systems. Sprawling power lines act like antennas, picking up the currents and spreading the problem over a wide area. The most famous geomagnetic power outage happened during a space storm in March 1989 when six million people in Quebec lost power for 9 hours: image.

Read more ....

Thursday, January 8, 2009

Report: Powerful Solar Storm Could Shut Down U.S. for Months

Photo: A big solar flare in December 2006. NASA

From FOX News:

A new study from the National Academy of Sciences outlines grim possibilities on Earth for a worst-case scenario solar storm.

Damage to power grids and other communications systems could be catastrophic, the scientists conclude, with effects leading to a potential loss of governmental control of the situation.

The prediction is based in part on major solar storm in 1859 caused telegraph wires to short out in the United States and Europe, igniting widespread fires.

It was perhaps the worst in the past 200 years, according to the new study, and with the advent of modern power grids and satellites, much more is at risk.

"A contemporary repetition of the [1859] event would cause significantly more extensive (and possibly catastrophic) social and economic disruptions," the researchers conclude.

Read more ....

Sunday, October 19, 2008

Protective Shield Of The Sun Is Shrinking


From The Sydney Morning Herald:

LONDON: The protective bubble around the sun that helps to shield the Earth from harmful interstellar radiation is shrinking and getting weaker, NASA scientists have discovered.

New data from the Ulysses deep-space probe show that the heliosphere, the protective shield of energy that surrounds our solar system, has weakened by 25 per cent over the past decade and is now at it lowest level since the space race began 50 years ago.

Scientists, baffled at what could be causing the barrier to shrink in this way, were set to launch a mission overnight to study the heliosphere.

The Interstellar Boundary Explorer, or Ibex, will orbit 240,000 kilometres above the Earth and "listen" for the shock wave that forms as our solar system meets interstellar radiation.

Read more ....