solar cycle 24

NASA May 20, 2003:
Hathaway predicts cycle 24 to begin Dec 2006

NASA Oct 2004:
"Hathaway and colleague Bob Wilson, both working at NASA's Marshall Space Flight Center, believe they've found a simple way to predict the date of the next solar minimum. "So, using Hathaway and Wilson's simple rule, solar minimum should arrive in late 2006.

NOAA Jan 6, 2006:
The next sunspot minimum is forecast to occur in late 2006 through mid 2007.

March 6, 2006:
For almost the entire month of February 2006 the sun was utterly blank. What's going on? NASA solar physicist David Hathaway explains: "Solar minimum has arrived."

NASA March 10, 2006:
"Like most experts in the field, Hathaway [NASA] has confidence in the conveyor belt model and agrees with Dikpati that the next solar maximum should be a doozy [30% to 50% stronger than the previous one].

NASA August 15, 2006:
"We've been waiting for this," says David Hathaway, a solar physicist at the Marshall Space Flight in Huntsville, Alabama. "A backward sunspot is a sign that the next solar cycle is beginning." The next cycle, Solar Cycle 24, should begin "any time now," returning the sun to a stormy state.


One year and four months later.....

Dec 14, 2007 NASA:
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. 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.

NASA March 28, 2008:
"Barely three months after forecasters announced the beginning of new Solar Cycle 24, old Solar Cycle 23 has returned."

NOAA & NASA June 27, 2008:
"The panel expects solar minimum to occur in March, 2008. {obviously this must be a typo and should read March, 2009}

NASA July 11, 2008:
"The sun is behaving normally. So says NASA solar physicist David Hathaway."
"There have been some reports lately that Solar Minimum is lasting longer than it should. That's not true. The ongoing lull in sunspot number is well within historic norms for the solar cycle."
"some observers are questioning the length of the ongoing minimum, now slogging through its 3rd year."

"It does seem like it's taking a long time," allows Hathaway, "but I think we're just forgetting how long a solar minimum can last."

November 7, 2008, NASA:
"After two-plus years of few sunspots, even fewer solar flares, and a generally eerie calm, the sun is finally showing signs of life. "I think solar minimum is behind us," says sunspot forecaster David Hathaway of the NASA Marshall Space Flight Center."

November 7, 2008, NASA:
"From January to September, the sun produced a total of 22 sunspot groups; 82% of them belonged to old Cycle 23. October added five more; but this time 80% belonged to Cycle 24. The tables have turned. Even with its flurry of sunspots,the October sun was mostly blank, with zero sunspots on 20 of the month's 31 days."

April 1, 2009:
"We're experiencing a very deep solar minimum," says solar physicist Dean Pesnell of the Goddard Space Flight Center.

"This is the quietest sun we've seen in almost a century," agrees sunspot expert David Hathaway of the Marshall Space Flight Center.

In 2008, the sun set the following records:

A 50-year low in solar wind pressure: Measurements by the Ulysses spacecraft reveal a 20% drop in solar wind pressure since the mid-1990s—the lowest point since such measurements began in the 1960s.

A 12-year low in solar "irradiance": Careful measurements by several NASA spacecraft show that the sun's brightness has dropped by 0.02% at visible wavelengths and 6% at extreme UV wavelengths since the solar minimum of 1996.

A 55-year low in solar radio emissions: After World War II, astronomers began keeping records of the sun's brightness at radio wavelengths. Records of 10.7 cm flux extend back all the way to the early 1950s.Radio telescopes are now recording the dimmest "radio sun" since 1955.

'Quiet Sun' baffling astronomers

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.

According to Prof Louise Hara of University College London, it is unclear why this is happening or when the Sun is likely to become more active again.

"There's no sign of us coming out of it yet," she told BBC News.

"At the moment, there are scientific papers coming out suggesting that we'll be going into a normal period of activity soon.

"Others are suggesting we'll be going into another minimum period - this is a big scientific debate at the moment."

In the mid-17th Century, a quiet spell - known as the Maunder Minimum - lasted 70 years, and led to a "mini ice-age".

This has resulted in some people suggesting that a similar cooling might offset the impact of climate change.

According to Prof Mike Lockwood of Southampton University, this view is too simplistic.

"I wish the Sun was coming to our aid but, unfortunately, the data shows that is not the case," he said.

Prof Lockwood was one of the first researchers to show that the Sun's activity has been gradually decreasing since 1985, yet overall global temperatures have continued to rise.

"If you look carefully at the observations, it's pretty clear that the underlying level of the Sun peaked at about 1985 and what we are seeing is a continuation of a downward trend (in solar activity) that's been going on for a couple of decades.

"If the Sun's dimming were to have a cooling effect, we'd have seen it by now."

'Middle ground'

Evidence from tree trunks and ice cores suggest that the Sun is calming down after an unusually high point in its activity.

Professor Lockwood believes that as well as the Sun's 11-year cycle, there is an underlying solar oscillation lasting hundreds of years.

He suggests that 1985 marked the "grand maximum" in this long-term cycle and the Maunder Minimum marked its low point.

"We are re-entering the middle ground after a period which has seen the Sun in its top 10% of activity," said Professor Lockwood.

"We would expect it to be more than a hundred years before we get down to the levels of the Maunder Minimum."

He added that the current slight dimming of the Sun is not going to reverse the rise in global temperatures caused by the burning of fossil fuels.

"What we are seeing is consistent with a global temperature rise, not that the Sun is coming to our aid."

Data from the Intergovernmental Panel on Climate Change (IPCC) shows global average temperatures have risen by about 0.7C since the beginning of the 20th Century.

And the IPCC projects that the world will continue to warm, with temperatures expected to rise between 1.8C and 4C by the end of the century.

No-one knows how the centuries-long waxing and waning of the Sun works. However, astronomers now have space telescopes studying the Sun in detail.

According to Prof Richard Harrison of the Rutherford Appleton Laboratory, Oxfordshire, this current quiet period gives astronomers a unique opportunity.

"This is very exciting because as astronomers we've never seen anything like this before in our lifetimes," he said.

"We have spacecraft up there to study the Sun in phenomenal detail. With these telescopes we can study this minimum of activity in a way that we could not have done so in the past."

May 8, 2009: A new active period of Earth-threatening solar storms will be the weakest since 1928 and its peak is still four years away, after a slow start last December, predicts an international panel of experts led by NOAA's Space Weather Prediction Center.


The panel predicts the upcoming Solar Cycle 24 will peak in May 2013 with 90 sunspots per day, averaged over a month. If the prediction proves true, Solar Cycle 24 will be the weakest cycle since number 16, which peaked at 78 daily sunspots in 1928, and ninth weakest since the 1750s, when numbered cycles began.

SUNSPOT 1019: New-cycle sunspot 1019 burst through the surface of the sun on May 31st
and it has been growing rapidly ever since. This movie from the Solar and Heliospheric Observatory (SOHO) shows the progress of the activeregion over a two-day period:

The sunspot's two dark cores are each about the size of Earth,
and they are crackling with A-class solar flares. During years of Solar Max (e.g., 2000-2002) we would consider such activity minor, but now, during the deep solar minimum of 2008-2009, it merits attention. The magnetic polarity and high latitude of the sunspot identify it as a member of new Solar Cycle 24, expected to peak in 2013. This makes sunspot 1019 a sign of things to come.