Solar Science

A blog of solar physics

David Hathaway: Mea Culpa

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I’m not going to add much more than to say that its enjoyable and refreshing to see a senior scientist admit that they were wholly wrong in their predictions.

How Long Will Our Sun Remain Quiet and Cosmic Rays Increase?

What Happened to 2006 Predictions of Huge Solar Cycle 24?

ISN’T IT ESPECIALLY STRANGE FOR YOU BECAUSE THREE YEARS AGO, ALL THE PHYSICS OF THE SUN THAT YOU AND NASA AND EVERYBODY ELSE WAS USING WERE ANTICIPATING THAT THIS COULD BE THE BIGGEST SOLAR MAXIMUM ON RECORD?

There were indications back then. I am writing a paper – it’s on my computer as we speak (laughs) – basically saying that I made a big mistake – myself and Bob Wilson – when we wrote a paper in 2006, suggesting Solar Cycle 24 was going to be a huge cycle based on conditions at that time. The problem we had with our prediction was that it was based on a method that assumes that we’re near sunspot cycle minimum.

We had just previously gone through three or four sunspot cycles that had been only ten years long each, so for the one in 1996 to 2006, it seemed like a reasonable assumption. But as we now know, we were off by at least two years. And if we take conditions on the sun now, it’s a completely different story. The conditions now – using even that same technique from 2006 – says that the next sunspot cycle is going to be half what we thought it was back in 2006.

Another big prediction in 2006 was based on a dynamo model – a model for how the sun produces magnetic fields – and it suggested a huge cycle.

But there also were people back at that time saying otherwise. A group of colleagues led by Leif Svalgaard, Ph.D., were looking at the sun’s polar fields and saying even at that point, the sun’s polar fields were significantly weaker than they had been before and those scientists back then predicted it was going to be a small cycle.

How Small Will Solar Cycle 24 Be?

…I’ve come around to that view now. I think there is little doubt in my mind now that we’re in for a small cycle. The big question now is how small? I think most of us are predicting small cycles. I think even the techniques I’m using now are suggesting HALF the size of the last three or four solar cycles, but my fear is that even that might be too big just from the fact that it’s taken so long for this Solar Cycle 24 to really get off the ground and start producing sunspots.

I have no doubt at this point that it’s going to be a little cycle. My current prediction is that it’s going to be about half of what we’ve seen in the last four solar cycles or so. But in my gut, I feel it’s going to be smaller than that! (laughs) It’s just so slow in taking off and the indicators that we see – both the polar fields and the geomagnetic indicators are lower than anything we’ve seen before.

So kudos to David Hathaway for writing a paper talking about how wrong his previous papers have been. Absolutely no sarcasm intended or implied.

Written by John A

October 31, 2009 at 2:58 am

Solar Science blog to go into extended minimum

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Folks

The Solar Science blog is on hiatus for the forseeable future. I have other commitments and a different focus which is causing me to cut out marginal uses of my time like maintaining this blog.

In the meantime, I recommend Solarcycle24.com and Watts Up with That for their coverage of solar issues.

If anyone knows of any other solar science resources on the Internet that I can link to, then tell me in the comments and I’ll add them

John

Written by John A

October 3, 2009 at 11:41 am

Posted in Uncategorized

Climate Change on Mars: Its all about the Sun

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This just in from NASA:

New, three-dimensional imaging of Martian north-polar ice layers by a radar instrument on NASA’s Mars Reconnaissance Orbiter is consistent with theoretical models of Martian climate swings during the past few million years. Alignment of the layering patterns with the modeled climate cycles provides insight about how the layers accumulated. These ice-rich, layered deposits cover an area one-third larger than Texas and form a stack up to 2 kilometers (1.2 miles) thick atop a basal deposit with additional ice.

“Contrast in electrical properties between layers is what provides the reflectivity we observe with the radar,” said Nathaniel Putzig of Southwest Research Institute, Boulder, Colo., a member of the science team for the Shallow Radar instrument on the orbiter. “The pattern of reflectivity tells us about the pattern of material variations within the layers.”

Earlier radar observations indicated that the Martian north-polar layered deposits are mostly ice. Radar contrasts between different layers in the deposits are interpreted as differences in the concentration of rock material, in the form of dust, mixed with the ice. These deposits on Mars hold about one-third as much water as Earth’s Greenland ice sheet.

It certainly isn’t carbon dioxide that’s causing any climate change on Mars.

Written by John A

September 23, 2009 at 2:05 pm

Posted in Uncategorized

SC24: Sunspots appear in both hemispheres

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Just when I thought we’d get to watch a single sunspot make its weary way across the surface of the Sun, a new sunspot group appears in the Northern Hemisphere. We haven’t seen a sight like this in a long time

Of course the Sun has surprised us before – one swallow not making a summer and all of that jazz – but I remain cautiously optimistic. It will be interesting to see if the new Northern Hemisphere spots last for at least a few days.

Boy, am I a glutton for punishment.

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Written by John A

September 23, 2009 at 10:27 am

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It comes from the Far Side..?

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After being starved of any significant solar activity for so long, any detection of a sunspot very nearly becomes headline news. Therefore when a significant spot is detected on the solar farside, people start writing furiously.

So what to do? The first detection of a potential (and substantial) sunspot in more than a month came from GONG

But will it survive to the nearside?

There’s something that might be a spot on the far eastern limb of the latest STEREO image

But GONG now shows nothing at all

GONG data as of 16th September 2009

GONG data as of 16th September 2009

So what to believe? The next few days should show whether we’re looking at a spot or a plage. I confess that the sensitivity of the seismic results interpreted by GONG are often less accurate as to whether we are seeing a solar disturbance (like a coronal hole or a prominence) or a real sunspot.

I suspect that this is continuation of a pattern we have been seeing for many months, a single sunspot or very small group with SC24 polarity passes in front of us, but nothing else happens and the Sun’s activity quickly falls back to very low levels.

Because of this phenomenon, the most likely response from the solar science community is likely to be muted, after so many false dawns.

Solarcycle24.com has produced a graph showing the remarkable difference between the spotless days between solar cycles 22 and 23 and between 23 and 24.

There’s no end in sight for this minimum.

Written by John A

September 16, 2009 at 9:15 pm

Posted in Solar Cycle 24

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Solar Climate Linkages

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Just a couple of interesting articles that I think deserve wider readership.

Henrik Svensmark on the coming global cooling: “enjoy global warming while it lasts” (this is a Google translation from Danish, so the English is a little crazy)

While the sun sleeps

HENRIK SVENSMARK, Professor, DTU, Copenhagen

Indeed, global warming stopped and a cooling is beginning. No climate model has predicted a cooling of the Earth, on the contrary. This means that projections of future climate is unpredictable, writes Henrik Svensmark.

The star which keeps us alive, has over the last few years almost no sunspots, which are the usual signs of the sun’s magnetic activity.

Last week, reported the scientific team behind Sohosatellitten (Solar and Heliospheric Observatory) that the number of sunspot-free days suggest that solar activity is heading towards its lowest level in about 100 years’. Everything indicates that the Sun is moving into a hibernation-like state, and the obvious question is whether it has any significance for us on Earth.

If you ask the International Panel on Climate Change IPCC, representing the current consensus on climate change, so the answer is a reassuring ‘nothing’. But history and recent research suggests that it is probably completely wrong. Let us take a closer look at why.

Solar activity has always varied. Around the year 1000, we had a period of very high solar activity, which coincided with the medieval warmth. It was a period when frosts in May was an almost unknown phenomenon and of great importance for a good harvest. Vikings settled in Greenland and explored the coast of North America. For example, China’s population doubled over this period. But after about 1300, the earth began to get colder and it was the beginning of the period we now call the Little Ice Age. In this cold period all the Viking settlements in Greenland disappeared. Swedes [were surprised to see Denmark to freeze over in ice], and the Thames in London froze repeatedly. But more serious was the long periods of crop failure, which resulted in a poorly nourished population, because of disease and hunger [population was reduced] by about 30 per cent in Europe.

Read on here

New linkage between solar cycle and Earth’s atmosphere discovered

Scientists discover surprise in Earth’s upper atmosphere

By Stuart Wolpert

Heejeong Kim and Larry Lyons

Heejeong Kim and Larry Lyons

UCLA atmospheric scientists have discovered a previously unknown basic mode of energy transfer from the solar wind to the Earth’s magnetosphere. The research, federally funded by the National Science Foundation, could improve the safety and reliability of spacecraft that operate in the upper atmosphere.

“It’s like something else is heating the atmosphere besides the sun. This discovery is like finding it got hotter when the sun went down,” said Larry Lyons, UCLA professor of atmospheric and oceanic sciences and a co-author of the research, which is in press in two companion papers in the Journal of Geophysical Research.

The sun, in addition to emitting radiation, emits a stream of ionized particles called the solar wind that affects the Earth and other planets in the solar system. The solar wind, which carries the particles from the sun’s magnetic field, known as the interplanetary magnetic field, takes about three or four days to reach the Earth. When the charged electrical particles approach the Earth, they carve out a highly magnetized region — the magnetosphere — which surrounds and protects the Earth.

Charged particles carry currents, which cause significant modifications in the Earth’s magnetosphere. This region is where communications spacecraft operate and where the energy releases in space known as substorms wreak havoc on satellites, power grids and communications systems.

The rate at which the solar wind transfers energy to the magnetosphere can vary widely, but what determines the rate of energy transfer is unclear.

“We thought it was known, but we came up with a major surprise,” said Lyons, who conducted the research with Heejeong Kim, an assistant researcher in the UCLA Department of Atmospheric and Oceanic Sciences, and other colleagues.

Read on here

Written by John A

September 11, 2009 at 12:13 pm

NASA on the disappearing sunspots

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This just in from NASA:

September 3, 2009: The sun is in the pits of the deepest solar minimum in nearly a century. Weeks and sometimes whole months go by without even a single tiny sunspot. The quiet has dragged out for more than two years, prompting some observers to wonder, are sunspots disappearing?

“Personally, I’m betting that sunspots are coming back,” says researcher Matt Penn of the National Solar Observatory (NSO) in Tucson, Arizona. But, he allows, “there is some evidence that they won’t.”

Penn’s colleague Bill Livingston of the NSO has been measuring the magnetic fields of sunspots for the past 17 years, and he has found a remarkable trend. Sunspot magnetism is on the decline:

Above: Sunspot magnetic fields measured by Livingston and Penn from 1992 – Feb. 2009 using an infrared Zeeman splitting technique.

“Sunspot magnetic fields are dropping by about 50 gauss per year,” says Penn. “If we extrapolate this trend into the future, sunspots could completely vanish around the year 2015.”

Hmmm, yes they could. But the solar magnetic field could simply be in a cyclical downturn of which this is a part. We need an expert!

“This work has caused a sensation in the field of solar physics,” comments NASA sunspot expert David Hathaway, who is not directly involved in the research. “It’s controversial stuff.”

The controversy is not about the data. “We know Livingston and Penn are excellent observers,” says Hathaway. “The trend that they have discovered appears to be real.” The part colleagues have trouble believing is the extrapolation. Hathaway notes that most of their data were taken after the maximum of Solar Cycle 23 (2000-2002) when sunspot activity naturally began to decline. “The drop in magnetic fields could be a normal aspect of the solar cycle and not a sign that sunspots are permanently vanishing.”

Yes, what he said.

Penn himself wonders about these points. “Our technique is relatively new and the data stretches back in time only 17 years. We could be observing a temporary downturn that will reverse itself.”

The technique they’re using was pioneered by Livingston at the NASA-supported McMath-Pierce solar telescope near Tucson. He looks at a spectral line emitted by iron atoms in the sun’s atmosphere. Sunspot magnetic fields cause the line to split in two—an effect called “Zeeman splitting” after Dutch physicist Pieter Zeeman who discovered the phenomenon in the 19th century. The size of the split reveals the intensity of the magnetism

If the solar magnetism continues to decline what could this mean for the Earth?

If sunspots do go away, it wouldn’t be the first time. In the 17th century, the sun plunged into a 70-year period of spotlessness known as the Maunder Minimum that still baffles scientists. The sunspot drought began in 1645 and lasted until 1715; during that time, some of the best astronomers in history (e.g., Cassini) monitored the sun and failed to count more than a few dozen sunspots per year, compared to the usual thousands.

Note that of course, they don’t mention that this coincided with the coldest part of the Little Ice Age. But that would be politically incorrect, wouldn’t it?

“Whether [the current downturn] is an omen of long-term sunspot decline, analogous to the Maunder Minimum, remains to be seen,” Livingston and Penn caution in a recent issue of EOS. “Other indications of solar activity suggest that sunspots must return in earnest within the next year.”

I’d love to know what those other indications are, because the prognostications of future solar activity have been startlingly poor from practically everybody.

I leave the last words to David Hathaway, who dares to speak the truth to solar science:

Whatever happens, notes Hathaway, “the sun is behaving in an interesting way and I believe we’re about to learn something new.”

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Written by John A

September 3, 2009 at 10:13 am

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