New solar cycle prediction - #NASA

An international panel of experts, led by the National Oceanic and Atmospheric Administration (National Oceanic and Atmospheric Administration or NOAA, in English) and sponsored by NASA, has issued a new forecast for the next solar cycle. Solar Cycle 24 will its maximum, say, in May 2013 with a sunspot number below average.

"If our prediction is correct, Solar Cycle 24 will have a maximum of 90 spots, the lowest number of all cycles counted since 1928, when Solar Cycle 16 peaked at 70 spots," says the head of the panel, Doug Biesecker of the Center for Space Weather Forecasts (Space Weather Prediction Center, in English) from NOAA.

It is tempting to describe a cycle of these characteristics as "weak" or "soft", but that might give the wrong impression.

"We still remain below average, any solar cycle is capable of producing severe space weather," notes Biesecker. "The great geomagnetic storm of 1859, for instance, took place during a solar cycle of the same size as we're predicting for 2013."

The storm that occurred in 1859, known as the "Carrington Event" in honor of the astronomer Richard Carrington, who witnessed this tremendous solar flare electrified transmission lines, caused fires in telegraph offices and produced Northern Lights so bright you could read the newspaper in its light reddish-green.

A recent report provided by the National Academy of Sciences, concluded that if a similar storm occurred today could cause between 1 and 2 billion dollars in damage to the infrastructure of our highly technological society, and lead to four to ten years to achieve full recovery. By comparison, Hurricane Katrina caused damage "only" 80 to 125 billion dollars.

Above: This chart represents the number of sunspots shows the maximum intensity measured in the last cycle, in blue, and the maximum intensity predicted for the next cycle in red. Credit: Center for Space Weather Prediction / NOAA. [More]

The latest forecast is based on a review of an earlier prediction, made ​​in 2007. That year, a panel of experts, divided into two positions, believed that solar minimum would occur in March 2008, followed by a strong solar maximum in 2011 or a weak peak in 2012. Competing models gave different answers and researchers were eager to know which is nearer the Sun

"It happened that neither of the two models was quite correct," says Dean Pesnell of Goddard Space Flight Center, who was the NASA representative in that panel. "The sun is behaving in an unexpected and very interesting."

Researchers have known of the solar cycle from mid-1800. The graphs represent the number of sunspots counted since those days are like a roller coaster, up and down with a period of approximately 11 years.

At first glance, seems to be a regular pattern, but predicting the peaks and valleys has proved problematic. Cycles vary in length between approximately 9 and 14. Some peaks are high, others low. The valleys are usually short, lasting only a couple of years, but sometimes spread and become much longer. In the 17th century, the sun sank into a period of 70 years with no stains, which is known today as the Maunder Minimum, and still baffles scientists.

Above: The average number of sunspots per year between 1610 and 2008. Researchers believe that the newly launched Solar Cycle 24 will be similar to the cycle that peaked in intensity in 1928, indicated with a red arrow on the graph. Credit: NASA / MSFC

Right now, the solar cycle is in a valley - the deepest in the last century. In 2008 and 2009, the sun has broken records of the Space Age for the lowest amount of spots, weak solar wind and the low solar irradiance. It has been more than two years that the Sun emits a solar flare of significant size.

"In our careers, we had never seen anything like it," says Pesnell. "Solar minimum has lasted much longer than the date predicted in 2007."

In recent months, however, the sun has begun to show signs of life, but very timid. Small spots and "proto-spots" sun begin to appear more frequently. Huge plasma flows on the solar surface (known as " flow zone ") begin to increase in intensity and move slowly toward the solar Ecuador. Radio astronomers have detected a small but significant increase in solar emissions in radio waves. All these things are the precursors of an awakening of Solar Cycle 24 and form the basis of new and nearly unanimous forecast provided by the panel of scientists.

According to the forecast, the sun should remain calm for at least another year. From the standpoint of research, that's good news because solar minimum has proved more interesting than anyone had imagined.

The low solar activity has a profound effect on the Earth's atmosphere, allowing it to cool and contract. The debris accumulates in orbit around the Earth because there is less aerodynamic drag. The quiet storm produces less solar wind around the magnetic poles of Earth. Cosmic rays are usually bounced by the solar wind, slip instead into the near-Earth environment. There are other side effects, too, that can only be studied under the sun remains quiet.

Meanwhile, the Sun cares little human committees. There could be more surprises, the panelists agree, and thus more forecast revisions.

"Go ahead and mark your calendar for May 2013," says Pesnell. "But mark it in pencil."

Source: Science & NASA