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Gingersnap
09-02-2008, 10:50 AM
Science
Sun Makes History: First Spotless Month in a Century

Michael Asher (Blog) - September 1, 2008 8:11 AM

The sun has reached a milestone not seen for nearly 100 years: an entire month has passed without a single visible sunspot being noted.

The event is significant as many climatologists now believe solar magnetic activity which determines the number of sunspots -- is an influencing factor for climate on earth.

According to data from Mount Wilson Observatory, UCLA, more than an entire month has passed without a spot. The last time such an event occurred was June of 1913. Sunspot data has been collected since 1749.

When the sun is active, it's not uncommon to see sunspot numbers of 100 or more in a single month. Every 11 years, activity slows, and numbers briefly drop to near-zero. Normally sunspots return very quickly, as a new cycle begins.

But this year -- which corresponds to the start of Solar Cycle 24 -- has been extraordinarily long and quiet, with the first seven months averaging a sunspot number of only 3. August followed with none at all. The astonishing rapid drop of the past year has defied predictions, and caught nearly all astronomers by surprise.

Interesting. Much more at the link.

Daily Tech (http://www.dailytech.com/Sun+Makes+History+First+Spotless+Month+in+a+Centur y/article12823.htm)

biccat
09-02-2008, 01:03 PM
According to data from Mount Wilson Observatory, UCLA, more than an entire month has passed without a spot. The last time such an event occurred was June of 1913. Sunspot data has been collected since 1749.
But what about the other side of the sun?

wilbur
09-02-2008, 02:58 PM
But what about the other side of the sun?

I was wondering the same thing.

Now I'm hearing there was actually a "sun-speck".... they downgraded a sunspot, like it was a (ex)planet called pluto, so they could have a record month of no sunspots:P

Gingersnap
09-02-2008, 03:08 PM
I was wondering the same thing.

Now I'm hearing there was actually a "sun-speck".... they downgraded a sunspot, like it was a (ex)planet called pluto, so they could have a record month of no sunspots:P

Who are "they"? :confused:

wineslob
09-02-2008, 04:14 PM
But what about the other side of the sun?

The Sun rotates.

Funny, we have less solar actvity and the Earth cools (however slightly). So much for the "The Sun has no effect on the Earth" meme.

biccat
09-02-2008, 04:24 PM
The Sun rotates.
I was going for humor more than anything. But thanks for the buzzkill ;)

wineslob
09-02-2008, 05:00 PM
I was going for humor more than anything. But thanks for the buzzkill ;)

I'm happy to help. :p


Another good article :http://www.dailytech.com/Sun+Makes+History+First+Spotless+Month+in+a+Centur y/article12823.htm

The Night Owl
09-02-2008, 06:45 PM
The Sun rotates.

Funny, we have less solar actvity and the Earth cools (however slightly). So much for the "The Sun has no effect on the Earth" meme.

No dice. From another thread...

http://www.sciam.com/article.cfm?id=no-sunshine-for-global-wa


The consistency meshes with solar physicists' latest understanding of how the sun works, the group notes. The sun's luminosity swings up and down by less than 0.1 percent in accord with an 11-year cycle of sunspots and faculae, bright areas of heightened output [see image above]. This cycle accounts for most of the sun's variability. Recent simulations reinforce the idea that convection inside the sun rapidly smoothes out internal hot spots before their concentrated heat can escape like an upwelling of magma, the researchers note. This inertia allows surface changes to have a discernible effect and explains why no additional sources of variation have been identified so far, they say.

megimoo
09-02-2008, 07:48 PM
Interesting. Much more at the link.

Daily Tech (http://www.dailytech.com/Sun+Makes+History+First+Spotless+Month+in+a+Centur y/article12823.htm)

The Solar Source of the Earth's Energy

Almost all of the energy that drives the various systems (climate systems, ecosystems, hydrologic systems, etc.) found on the Earth originates from the Sun.

Solar energy is created at the core of the Sun when hydrogen atoms are fused into helium by nuclear fusion. For each second of this nuclear process, 700 million tons of hydrogen are converted into 695 million tons of helium. The remaining 5 million tons are turned into electromagnetic energy that radiates from the Sun's surface out into space.

The radiative surface of the Sun, or photosphere, has an average temperature of about 5800 Kelvins. Most of the electromagnetic radiation emitted from the Sun's surface lies in the visible band centered at 0.5 m. The total quantity of energy emitted from the Sun's surface is approximately 63,000,000 Watts per square meter (W/m2 or Wm-2).

The energy emitted by the Sun passes through space until it is intercepted by planets and other celestial objects. The intensity of solar radiation striking these objects is determined by a physical law known as the Inverse Square Law (see topic 6f). This law merely states that the intensity of the radiation emitted from the Sun varies with the squared distance from the source. As a result of this law, if the intensity of radiation at a given distance is one unit, at twice the distance the intensity will become only one-quarter. At three times the distance, the intensity will become only one-ninth of its original intensity at a distance of one unit, and so on.

Given the amount of energy radiated by the Sun and the average Earth-Sun distance of 149.5 million kilometers, the amount of radiation intercepted by the outer limits of the atmosphere can be calculated to be around 1370 W/m2. For general purposes, the energy output of the Sun can be considered constant.

This of course is not entirely true. Scientists have shown that the output of the Sun is temporally variable. Some researchers have also suggested that the increase in the average global temperature over the last century may have been solar in origin. This statement, however, is difficult to prove because accurate data on solar output of radiation only goes back to about 1978
http://www.physicalgeography.net/fundamentals/6g.html