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Fraser
2004-Oct-18, 06:33 PM
SUMMARY: On October 11, solar astronomers saw something they haven't seen on the Sun in six years... nothing. Not a single sunspot. Within a couple of days, of course, a sunspot popped up, and they're on the Sun right now. This is a clear indication to astronomers that the Sun is on its way to the low point of its 11-year cycle of activity, called the "solar minimum". During the solar minimum, the Sun can be without spots for days or even weeks, and solar flares subside. Astronauts will breath a sigh of relief; it's a safer time to be out in space.

What do you think about this story? Post your comments below.

StarLab
2004-Oct-18, 07:08 PM
Astronauts will breath a sigh of relief; it&#39;s a safer time to be out in space. And at the exact same time, the Bush Administration is putting NASA through a budged cut. :rolleyes: <_< :ph34r: :unsure: :mellow: :huh: :lol: -_- :angry: :( :wacko: :ph34r: :blink:

om@umr.edu
2004-Oct-18, 08:58 PM
Politics aside, I am delighted our NASA and SOHO scientists are spending more time studying the Sun.

That is of critical concern to taxpayers. Clearly the Sun is not the steady, well-behaved fusion reactor that was assumed for many decades.

With kind regards,

Oliver
http://www.umr.edu/~om

Darth Maestro
2004-Oct-19, 01:46 AM
What amazes me most about the Universe is how infinitely complex it is, yet it is still bounded by simplicity (meaning that mere humans can come to understand it). Ultimately we are infinitely intelligent yet bounded by time. Amazing how it works&#33; Something as complex as the sun needs time and observations to understand it ... to bad NASA funding is getting cut.

om@umr.edu
2004-Oct-24, 04:04 AM
It would be interesting to see if careful measurements of the Fe/H ratio from line spectra in the photosphere correlates with the number of sunspots over the 22-year solar cycle.

It is intriguing that Maunder minimum stars, with low sunspot numbers over a longer period of time, have a high Fe/H ratio.

http://www.berkeley.edu/news/media/release...1_maunder.shtml (http://www.berkeley.edu/news/media/releases/2004/06/01_maunder.shtml)

With kind regards,

Oliver
http://www.umr.edu/~om

AstroStart.nl
2004-Oct-24, 10:09 AM
And in the future this will be seen with the biggest solartelescope of the world: the Chinese solar telescope. It will be launched in 2008.

om@umr.edu
2004-Oct-24, 01:18 PM
Originally posted by AstroStart.nl@Oct 24 2004, 10:09 AM
And in the future this will be seen with the biggest solartelescope of the world: the Chinese solar telescope. It will be launched in 2008.
Hey, that&#39;s great news&#33; Is there a web site where we can read about the Chinese solar telescope?

It was a Chinese graduate student, Golden Hwaung, who help uncovered evidence of severe mass separation in the Sun over 20 years ago, in the early 1980&#39;s.

With kind regards,

Oliver
http://www.umr.edu/~om

om@umr.edu
2004-Oct-24, 01:33 PM
Here&#39;s a web page about the Chinese solar telescope (SST) that was updated yesterday.

http://english.sohu.com/20041023/n222640228.shtml

Here are a few informative quotes:

"The SST will be used to study the solar magnetic field, fine structures of the sun surface, the energy accumulation and release of solar flares and sun-earth interaction, Ai said.

The solar magnetic field, which dominates solar activities, is very hard to be measured. British Journal of Physics listed observation of the solar magnetic field among the four most difficult physical issues of the 21st century, together with quanta gravitation, fusion-related energy and pyro-superconductivity.

Before building space telescopes, global scientists gazed at the sun via earth surface-based telescopes. However, the observation from the earth will be affected by the aerosphere, which makes some key scientific data not so accurate.

Jin Shengzhen, principal investigator for the project, said the Chinese SST will be round, with a diameter of 70 kilometres, on the solar surface.

As a fixed star nearest to the earth, the sun is the only source of light and heat for the earth. Scientists regard solar research as the key to unraveling the evolution of the solar system and even the whole cosmos.

Experts estimate the total investment into the project at 1 billion yuan (US&#036;120 million)."

That is less than half the cost of NASA&#39;s recent Genesis Mission to collect solar wind atoms.

With kind regards,

Oliver
http://www.umr.edu/~om

Dennison
2004-Oct-25, 08:39 AM
Yep, I&#39;m a noob with the Sun =P

Are there any actually uses of Sunspots? They&#39;re only cooler bits of the Sun

om@umr.edu
2004-Oct-25, 01:18 PM
Dennison,

Perhaps you under-estimate the importance of sunspots, a sign of solar magnetic fields.

They may contain important information about the internal workings of the Sun and long-range climate changes.

We really know very little about the Sun, the energy source for essentially everything that happens on Earth including our every thought and action.

1. Its surface is 91% Hydrogen and 9% Helium, the two lightest elements.

2. It emits light, energy, H, He, and neutrinos.

3. Sunspots are surface evidence of an internal, 22-year, magnetic cycle.

4. A much longer magnetic cycle likely produced Europe&#39;s Little Ice Age, when there was almost no sunspot activity from 1645 until 1714, the "Maunder minimum".

5. About 10% of Sun-like stars are in an inactive state like the "Maunder minimum".

6. A recently completed survey of such stars found that their surfaces contain much more metals than the Sun&#39;s surface, i.e., the Fe/H ratio is much higher than that at the Sun&#39;s surface.

http://www.berkeley.edu/news/media/release...1_maunder.shtml (http://www.berkeley.edu/news/media/releases/2004/06/01_maunder.shtml)

So Dennison, these cooler bits of the Sun called sunspots may be the key to understanding the internal workings of the Sun, solar magnetic fields, and long-range climate changes like the Little Ice Age.

With kind regards,

Oliver
http://www.umr.edu/~om

Duane
2004-Oct-25, 05:52 PM
I agree totally with Oliver here, the studies of the sun&#39;s magnetic fields and their causes is of great importance to understanding both the sun itself and its affect on our little ball of dirt.

It should be noted that the Maunder Minimum is only one of several minimums that have been noted. While it certainly appears that the minimums correlate with low sunspot activity, there also seem to be periods of low sunspot activity that are not connected to periods of lowered earthly temperatures.

It should also be noted that there are periods of increasing average temperatures (an example is the period between 900 and 1100 AD, when Greenland was warm enough to support crop growth). It might be the case that we are in such a period now.

Finally, I would note that although the stars referred to by Oliver are "richer" in heavy metals, it is also thought that the stars measured are not sun-like, in that they are usually much older, on the order of 4Billion years, and appear to be moving off of the main sequnce and on their way to becoming red giants.

BTW, nice find Oliver :) Makes you wonder why it has to be so expensive for the good ole US to send up similar payloads, doesn&#39;t it?

suntrack2
2004-Oct-26, 01:32 PM
temperature has rise on sun in this six years or cool down?
are we correct in counting the next sunspot cycle due to this the gap of six years has aside? may magnetic field of the sun is rising substantially? or the temperature scattered on some parts of the sun and no spots seen?

sunil

om@umr.edu
2004-Oct-26, 02:19 PM
Sunil,

These are important questions.

Unfortunately, the honest answer is that we do not know all the answers.

The standard solar model explains neither solar magnetic fields, nor long-range climate changes, nor solar sunspot cycles.

Blind belief in this Bible of solar astrophysics has otherwise reasonable people using names like "pseudo-science", "fools", etc. when faced with experimental evidence that:

The Sun is not a steady, H-fusion reactor.

The Sun did not formed instantly as a homogeneous ball of Hydrogen and Helium, with only traces of the other 81 elements.

In my opinion, we will not begin to understand solar magnetic fields, long-range climate changes, and solar sunspot cycles, if we are unwilling to consider the possibility that the interior of the Sun may be composed of something other than Hydrogen and Helium.

With kind regards,

Oliver
http://www.umr.edu/~om

Duane
2004-Oct-26, 02:44 PM
That is an interesting little dissertation OM. I think a couple of sunil&#39;s questions are answerable--namely that six years is too short a time to give any answer to the question "is the temperature rising or cooling off", it does not appear this one day gap is anything other than a manifestation of the sun entering its solar minimum phase, there is no evidence (so far) that the magnetic field is changing, and there is no scattering of temperature, although I am not sure I fully understand the question.

Surely Oliver, you could at least take the time to answer the questions posed before launching into yet another rant about the make up of our star.

I have to admit my initial reaction is to delete your last comment. It is another back-door attempt to argue the iron sun theory, framed in a manner intended to provoke a responce. A childish ploy Dr Manuel, and one I would have thought beneath you.

It is true that the Standard Solar Model (SSM) does not yet explain the solar magnetic field nor sunspots. Having said that,. research is moving closer and closer to answers for both.

There are explanations for long-term climate changes, including the slow increase of output from the sun due to hydrogen depletion. This, by the way, is something the neutron cored sun could not reconcile.

It has never been accepted that the sun is a "steady-hydrogen fusion reactor" except in the context of several billions of years of life. Short-term fluctuations are not accopunted for in the model, as it attempts to explain the life cycle of a star like the sun--not day to day fluctuations.

The SSM does not state the sun arose "instantly", rather it states that the sun formed as a result of the collapse of a mixed cloud of mostly hydrogen, accretting material over the course of several millions of years, and precipitated and added to by the material of nearby supernova explosions, Wolfe-Rayet star material, and red giant star atmospheres.

In my opinion, any theory lives or dies by its application to that which is observed.
In the case of a star filled with something other than hydrogen, there is no observational evidence. None. Nil. Nada. Even the very meteorites upon which the theory was built have been shown to include material from multiple injection events--something the theory says did not happen.

If you choose to reply, do it in the correct forum or I will delete it. Capice?

om@umr.edu
2004-Oct-26, 09:38 PM
Sunil,

Duane&#39;s first paragraph is correct.

Answers to some of your questions about solar magnetic fields, climate changes, and sunspot cycles were published last year in a paper not limited to the Standard Solar Model (SSM) of a Hydrogen-filled Sun.

"Superfluidity in the Solar Interior: Implications for Solar Eruptions and Climate", Journal of Fusion Energy, Volume 21 (2003) pages 193-198.

http://www.umr.edu/~om/abstracts2003/jfe-s...perfluidity.pdf (http://www.umr.edu/~om/abstracts2003/jfe-superfluidity.pdf)
http://www.umr.edu/~om/abstracts2003/jfe-s...uperfluidity.ps (http://www.umr.edu/~om/abstracts2003/jfe-superfluidity.ps)

However, we still have a very meager understanding of the internal workings of the Sun.

In my opinion, there will be no advancement in understanding the origin of solar magnetic fields, long-range climate changes, and solar sunspot cycles by those who are unwilling to consider the possibility that the interior of the Sun may consist of something other than Hydrogen and Helium.

The results of future studies will decide if there is any validity to my opinions.

With kind regards,

Oliver
http://www.umr.edu/~om

Algenon the mouse
2004-Oct-28, 03:45 AM
Okay, I am confused. I have read and been taught that there is a correlation between the number of sunspots and the temp of the earth. Wasn&#39;t it warmer during the 10th century due to an increase number of sunspots allowing the Vikings to travel to North America? I know that they run in cycles of 22 years....

antoniseb
2004-Oct-28, 01:17 PM
Originally posted by Algenon the mouse@Oct 28 2004, 03:45 AM
I have read and been taught that there is a correlation between the number of sunspots and the temp of the earth. Wasn&#39;t it warmer during the 10th century due to an increase number of sunspots allowing the Vikings to travel to North America?
The correlation between sunspot number and temperature is averaged out over many years. Just because there are three of four days of no spots during the solar minimum doesn&#39;t mean we&#39;re expecting snow in Miami.

BTW, we have only indirect knowledge of the number of sunspots during the 10th Century. No one had the ability to see and count them back them.

om@umr.edu
2004-Oct-28, 02:40 PM
Originally posted by Algenon the mouse@Oct 28 2004, 03:45 AM
I have read and been taught that there is a correlation between the number of sunspots and the temp of the earth.
There is indeed good anecdotal evidence for such a link.

The link is not established for the 22-year solar cycle. That is not surprising. The Sun is huge. Residual heat stored in the Sun tends to moderate short-term varations.

Long-term solar cycles show a link between sunspots and Earth&#39;s climate.

See the paper by Dr Theodor Landscheidt, “SOLAR ACTIVITY: A DOMINANT FACTOR IN CLIMATE DYNAMICS

http://www.john-daly.com/solar/solar.htm

Two problems:

1. The time scale for these solar variations is long compared to our life-spans.

2. There is only a short record of careful scientific observations on the Sun.

With kind regards,

Oliver
http://www.umr.edu/~om

suntrack2
2004-Oct-30, 11:07 AM
sunspots are not static in the one area, when they observed it during 6 years the spots may be on the invisible part of the sun from earth&#33;

om@umr.edu
2004-Oct-30, 01:13 PM
Originally posted by suntrack2@Oct 30 2004, 11:07 AM
sunspots are not static in the one area, when they observed it during 6 years the spots may be on the invisible part of the sun from earth&#33;
Right, sunil.

We see 2-pi solar geometry, rather than 4-pi geometry.

Like looking at a basket-ball. We see only half of the Sun&#39;s surface.

There were no sunspots on one half of the Sun on the day this story appeared.

The Sun rotates. We are not always looking at the same side. The entire surface seems to follow the 22-year solar cycle and longer ones.

With kind regards,

Oliver
http://www.umr.edu/~om

Duane
2004-Oct-30, 04:59 PM
There were no sunspots on one half of the Sun on the day this story appeared.


Sorry, but that&#39;s incorrect. There were no sunspots at all. SOHO allows for very precise measurements through helioseismology (http://soi.stanford.edu/results/heliowhat.html), which pinpoint sunspots even when they are not in our direct line of sight. In this case, there were no sunspots over the entire surface of the sun.

This is not all that unusual by the way. It occurs fairly often when the sun is at the minimum of its 22 year cycle.

om@umr.edu
2004-Oct-31, 03:53 AM
Originally posted by Duane@Oct 30 2004, 04:59 PM
There were no sunspots at all.

SOHO allows for very precise measurements through helioseismology (http://soi.stanford.edu/results/heliowhat.html), which pinpoint sunspots even when they are not in our direct line of sight.

In this case, there were no sunspots over the entire surface of the sun.

Thanks, Duane, for the correction.

I was unaware that helioseismology can detect sunspots on the reverse side of the Sun.

Which oscillation modes (p, g, f) are used to detect sunspots?

Are there any size limits on the sunspots detected in this manner?

A reference to sunspot detection by helioseismology would be helpful.

With kind regards,

Oliver
http://www.umr.edu/~om

Duane
2004-Nov-01, 06:30 PM
I already tied to a site Oliver. Just click on the word helioseismology. It also has a number of links to other sites that are more subject specific.

Duane
2004-Nov-01, 07:16 PM
This is a short reprint of a Discovery article (May 2004) written by Dana Mackenzie:



ACROSS SAN FRANCISCO BAY FROM LIN, A GROUP OF SCIENTISTS AT STANFORD University is looking at the sun&#39;s interior through a remarkable technique called helioseismology. The method uses optical sensing devices to detect movement of solar gases, much as seismologists can detect tremors in the earth. "There are sound waves going every which way in the sun," says group member Philip Scherrer, one of the 12 principal investigators for the Solar and Heliospheric Observatory (SOHO), a joint project of NASA and the European Space Agency. The sound waves come from the churning of gases in the sun&#39;s convective layer. In SOHO videos, the sun appears to have hundreds of thousands of flickering lights on its surface. Each flicker, called a granule, is a column of gas about 600 miles wide, which vibrates up and down about once every five minutes. Think of each one as a 600mile-wide drumhead and you can understand why the sun is a noisy place.

Scherrer and his colleagues at Stanford watch for echoes of these drumbeats. Every drumbeat will echo numerous times, as the sound waves go into the sun and come back out and bounce off the surface and go back in, over and over. Eventually, after several bounces, they may come out close to their starting point again. A roomful of computers watch for these reverberations 24 hours a day. Amid the cacophony of a million drums, they try to pick out the sound of a single drum and its echo from roughly a million miles away on the opposite side of the sun.

When they do pick up an echo, physicists can learn a great deal about the sun&#39;s interior. Sound waves do not travel equally fast at all temperatures. The hotter the gases, the faster they go. So a sound wave that passes deep through the interior of the sun to the opposite side and bounces back will return sooner than one that makes lots of little bounces close to the surface. The difference in transit time allows physicists to take the temperature of the regions the sound waves pass through. The technique is even sensitive enough to measure the temperature under a single sunspot. Scherrer and his colleagues have showed that although a sunspot is cooler on the sun&#39;s surface, it traps a layer of hotter gas beneath it.


The most spectacular consequence of this discovery is the ability to detect sunspots on the unseen side of the star-a possibility first broached by Douglas Braun and Charles Lindsey, solar researchers at NorthWest Research Associates in Boulder, more than 10 years ago. If there is an active sunspot region on the other side of the sun, Braun and Lindsey argued, the sound speed should increase underneath it because of the hotter gas under the spots. That speeds up the round trip of a drumbeat by a few seconds.

At first "we heard a lot of skepticism about the idea," Braun says. Lindsey is blunter: "Some people thought it was pie-inthe-sky craziness." And it didn&#39;t work when Lindsey and Braun looked at the sun through Earth-based telescopes. "All we got was noise," Braun says. "We really needed 24 hours of observation time to reduce the noise."

When SOHO was launched in 1995, it provided the perfect roundthe-clock viewing platform. So in 1999, Braun and Lindsey decided to try their idea again. This time it was a stunning success: Their computer program produced fuzzy yet unmistakable images of sunspots on the far side. Five years later, this amazing feat has become routine. (The far side of the sun can be observed every day at www.spaceweather.com.)

Far-side imaging even provided plenty of advance warning of the gamma-ray flare in 2002 that pleased Lin. The active region it came from, 10039, had grown larger throughout its transit across the far side. Similarly, region 10486, the main source of last fall&#39;s storms, drew researchers&#39; attention long before the sun rotated and the region came around to the front. Besides showing up like a big red bruise on the helioseismological maps of the far side, it had released coronal mass ejections that could not be traced to any region on the near side. The eruption had also emitted ultraviolet light that reflected off interplanetary hydrogen gas and back into SOHO&#39;s cameras. "When you see all three of these things together, it gives you the picture that something spectacular is happening on the far side," says St. Cyr. **Emphasis added**


PS: Spaceweather.com (http://spaceweather.com/) has live coverage of the sun. You can see the sunspots in real time.

om@umr.edu
2004-Nov-01, 10:58 PM
Thanks, Duane.

That is fascinating&#33;

I found no size limits for sunspot detection on the reverse side of the Sun, but they can obviously detect large ones there.

Thanks,

Oliver
http://www.umr.edu/~om