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Activity and variation
Are there any actual astronomers here? Solar activity is not the same as solar variation. What is the appropriate term for significant things that the sun does? The most significant things I know about are:
- sunspots and sunspot number - these vary a lot, on an 11-year (or 22-year) cycle
- solar wind - this changes in lockstep with the sunspots, right?
- solar radiation (i.e., "sunlight" ) - this varies vary little (hence the concept of a "solar constant")
What's the term for changes in solar activity, especially cyclic changes? Right now solar activity => solar variation but that makes no sense. I tried making "Solar variability" as a disambig page, but is that really the solution? --Uncle Ed (talk) 23:28, 3 February 2012 (UTC)
- Hi Ed. Strictly speaking, "solar activity" is "what's going on", and "solar variation" is "how much is what's going on changing"? However, the two are so closely coupled that the terms are effectively used to describe the same thing. The solar constant isn't a constant. It does indeed change with solar activity, but only fairly little (which is why it only has a minor effect on global warming, which is why deniers often make solar variation seem to be BIGGER so they can pretend "it's not CO2"). If you check the very first image in the article, you can see that the red line (yearly variations in "the solar constant") very closely matches the direct indicators of solar activity. You can also see that the change over time is small - about 1 W/m, or somewhat less than 0.1%. This is not measurable with pre-modern instruments, and it is much less than the ~3.5% yearly variation that we see due to the eccentricity of the earth's orbit. That's why the solar constant is called "constant", although it really is not. See etymological fallacy. ;-) --Stephan Schulz (talk) 10:32, 4 February 2012 (UTC)
- Thanks for your courteous and detailed response. I wonder, though, if both of us are using words the same way.
- I have been thinking that "changes in solar activity" includes both (1) the fairly little changes in the solar constant and (2) changes in sunspots. Note that I have turned Solar activity into a disambig page.
- The part I think is clear is that Solar radiation reaching the Earth (as irradiance) varies only fairly little. The part that's not clear is that changes in sunspots affect the solar wind, which in turn affects the amount of cosmic rays which enter the earth's atmosphere.
- Some "deniers" are concerned with irradiance, but others are concerned with cosmic rays. Is there a term for changes in solar activity which comprises both solar radiation changes and solar wind changes? Or does "solar variation" refer only to the former? --Uncle Ed (talk) 16:06, 4 February 2012 (UTC)
- I don't think it's just "deniers" who are concerned with irradiance and cosmic rays. Very serious scientists are engaged in very material scientific endeavors related to the solar irradiance variation and cosmic ray variation. I would say that solar variation deals with variation in the solar output and also with other variations with the sun like variations in the sun's magnetic field & solar wind which in turn has an effect on cosmic rays hitting the earth. So in the climate section of this page, heaven help me for saying this, we should note that variations in the solar magnetic field & solar wind may cause an impact to cosmic rays hitting the earth. However, I stand by my assertion that this page should be mostly about solar variation (the actual physical changes to the sun) and that the terrestrial climate topic and climate change and other impacts of the sun on the earth should be handled in their respective pages with only summaries here.174.49.84.214 (talk) 20:34, 9 February 2012 (UTC)
- Some "deniers" are concerned with irradiance, but others are concerned with cosmic rays. Is there a term for changes in solar activity which comprises both solar radiation changes and solar wind changes? Or does "solar variation" refer only to the former? --Uncle Ed (talk) 16:06, 4 February 2012 (UTC)
Ed, here is some more thinking on things that vary:
- sunspots and sunspot number - these vary a lot, on an 11-year (or 22-year) cycle
- solar wind - this changes in lockstep with the sunspots, right?
- solar radiation (i.e., "sunlight" ) - this varies vary little (hence the concept of a "solar constant")
- Sun's Magnetic Field Strength - varies with the sunspot cycle and with the conveyor belt cycle
- Sun's Magnetic Field Pole - It flips from time to time
- Sun's Great Conveyor Belt - varies in speed over time and we think has a longer term impact on the sun
- CME's - vary depending on a whole bunch of variables
Then beyond that, we have longer term solar variations like the fact that the sun is slowly getting hotter as it progresses along the main sequence. This page though seems to not be focused on that. It appears largely to have been built to promote or detract from AGW theory. I would like it to be more about our Sun's Variations but I'm outvoted largely. I'd engage Geoffrey Landis. He edits here and while his time is limited he is a Physicist from NASA who knows his stuff and is very balanced. 174.49.84.214 (talk) 15:06, 10 February 2012 (UTC)
Abbot's solar variation tool
Hi everyone! I just uploaded an image of Charles Greeley Abbot utilizing a tool which, I believe, he uses to "read" solar variation. Perhaps it will be of some use for this article! You can find the image here. -- Sarah (talk) 19:21, 11 April 2012 (UTC)
- What fun. Certainly gives historical perspective. CarolMooreDC 20:54, 11 April 2012 (UTC)
- I had a look, but I'm not sure what the picture is of. Guessing, I'd say it was some kind of mechanical fourier-analysis device William M. Connolley (talk) 21:16, 11 April 2012 (UTC)
new review paper
This is a sort of todo note for me or anyone else that has more time than me. A new review article came out this morning on Solar Irradiance Variation and climate. It seems to be pretty well written and could definitely be used to improve that section of this article. Sailsbystars (talk) 15:19, 13 June 2013 (UTC)
TSI
There is an inconsistency between the presented TSI graph, the graph of sunspot numbers and data available from NASA SORCE. I am looking at http://lasp.colorado.edu/home/sorce/data/tsi-data/#historical and find
http://lasp.colorado.edu/data/sorce/total_solar_irradiance_plots/images/tim_tsi_reconstruction.jpg
which is not consistent with what is presented on this encyclopedia page.
66.127.213.130 (talk) 19:33, 7 October 2013 (UTC)dogsinlove
- Which of our graphs are you talking about? File:Carbon14-sunspot-1000px.png? In what way are the two graphs inconsistent? William M. Connolley (talk) 19:57, 7 October 2013 (UTC)
Historical perspective
Is this quote really helpful? First off, it talks about weather prediction, not climate. The quote itself is ambiguous, open to interpretation as either: "history has shown time and again that it is pseudo-science" or as "in those days it was seen as pseudo-science, but now we have a better understanding". The intro of the source text would be a better choice imo:
- Since it is the Sun's energy that drives the weather system, scientists naturally wondered whether they might connect climate changes with solar variations. Yet the Sun seemed to be stable over the timescale of human civilization. Attempts to discover cyclic variations in weather and connect them with the 11-year sunspot cycle, or other possible solar cycles ranging up to a few centuries long, gave results that were ambiguous at best. These attempts got a well-deserved bad reputation. Jack Eddy overcame this with a 1976 study that demonstrated that irregular variations in solar surface activity, a few centuries long, were connected with major climate shifts. The mechanism was uncertain, but plausible candidates emerged. Ssscienccce (talk) 20:18, 20 October 2013 (UTC)
- The article itself is rife with such conflicts. I don't expect an easy resolution. Batvette (talk) 12:50, 7 November 2013 (UTC)