Solar Science

A blog of solar physics

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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.

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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

Posted in Uncategorized

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SOHO back online: Sun still blank

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It’s difficult sometimes to carry on a blog when the primary focus of your discussion doesn’t do anything. That’s the nature of solar minima, I guess, but particularly true when you have an apparent regime change in the solar cycle.

The latest news is that SOHO is back online after a glitch forced the software onboard to be reloaded with new commands, and mission controllers took an opportunity to bake all of the CCDs onboard the spacecraft to remove dead pixels.

Today the Sun is blank.

EIT195-23-8-2009

This image from the EIT (Extreme ultra-violet Imaging Telescope) at 195 Angstroms show no spots and no significant coronal holes.

Written by John A

August 22, 2009 at 2:30 pm

Is the Earth's magnetic field a cosmic ray funnel?

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Portrait of Henrik Svensmark

Portrait of Henrik Svensmark

In this world of rampant climate alarmism, its to be expected that theories and hypotheses which do not support the AGW theory will get the full treatment of bad analysis and character assassination. After all,  where’s the funding going to go if there’s an alternative theory that bombs the bridge in front of the gravy train?

One such is Dr Henrik Svensmark‘s hypothesis on the modulating effect of the solar magnetic field on the Earth’s climate. In the recent article in the New York Times on the solar cycle that I recently mentioned, we have this:

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.

All well and good. But then there’s always someone who produces a sophisticated argument why you shouldn’t believe your own lying eyes.

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.

Would the Earth’s magnetic field “funnel cosmic rays”? This was taken up by Stephen Ashworth in an email to Benny Peiser’s CCNet mailing list:

Dear Benny,

Kenneth Chang in the New York Times reports that some observations seem inconsistent with the solar magnetic field–cosmic ray–cloud formation hypothesis.  He wrote (CCNet 113/2009 — 21 July 2009, item 3):

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. [sic — he clearly means the *reduction* in cosmic ray influx to the Earth in recent decades of the more active Sun — SA]

I am skeptical about Dr Sloan’s claim.  The reason is as follows.

A few years ago I read a suggestion that an interstellar space probe might be able to do a flyby of the star Sirius, and use its gravity to redirect itself to a subsequent flyby of Procyon, in the same way that Pioneer, Voyager and other probes have used the gravity of Jupiter to redirect themselves to Saturn and beyond.  I have a formula for the change in direction caused by a flyby of a massive body, so I was able to check this idea numerically.

It turned out that if the interstellar probe was travelling at a speed that was a significant fraction of the speed of light, say 0.1c — which it would have to if it was to reach Sirius in only a few decades flight time — then the deflection of its trajectory even on a flyby which grazed the star’s atmosphere was only in the region of one degree, totally insufficient to redirect it to Procyon.

The lesson was that the gravitational fields of planets and even stars (Sirius is more massive than our Sun) are almost imperceptible to a vehicle if it is travelling at such a high speed.

Cosmic ray particles come into the Solar System at a significant fraction of the speed of light.  I would therefore expect them to be largely immune to our local gravitational and magnetic fields.  I would not expect Earth’s magnetic field to funnel them towards the poles, as it does with the lower-energy solar particle flux.  (Presumably someone has already checked this numerically?)

It would seem that Svensmark’s cosmic ray–cloud formation hypothesis depends on the difference in strength between the Sun’s and the Earth’s magnetic fields: the Sun being strong enough to modulate the cosmic ray flux in the inner Solar System over its longer-term cycles of activity, while the Earth is too weak to redistribute incoming particles geographically during their last second or so of flight before hitting the atmosphere.

Best wishes,

Stephen Ashworth
23 July 2009

Stephen Ashworth, Oxford, U.K.
http://www.astronist.demon.co.uk/

Quite so. Cosmic rays travel at significant percentages of the speed of light and wouldn’t be deflected significantly by the Earth’s weak magnetic field.

I wonder if Terry Sloan would care to answer? Someone should ask him.

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Written by John A

July 25, 2009 at 4:08 pm

Posted in Uncategorized