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Is the solar brightness dependant on how many solarspots

  1. Apr 6, 2010 #1

    I have a question about sunspots, to which the answer i could not find using google. Is the solar brightness dependant on how many solarspots are on the solar surface? I know that sunspots are cooler than the rest of the solar surface, however, the faculas that exist next to solar spots are hotter and therefore brighter.

    Can anyone help me with this?


    Max Planck
  2. jcsd
  3. Apr 6, 2010 #2


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    Re: Sunspots

    Sun spots appear to be correlated with Earth's climate...which would suggest to me that perhaps the luminosity is related. For example, during the Maunder minimum where there appeared to be very few sun spots for a period of 60 years or so, the Earth experienced a "little ice age" where temperatures went down quite a bit. It seems that fewer sunspots mean cooler Earth. This correlation is not very well understood.

    This whole field is quite poorly understood. You can see this wikipedia article for more: http://en.wikipedia.org/wiki/Maunder_minimum
  4. Apr 7, 2010 #3
    Re: Sunspots

    A warm hello to you, Max. Welcome to Physics Forums. I'm extremely fasinated by your question. I've spent a few hours attempting to do a decent search on the subject matter you provided and did discover:

    1. The Solar 'Constant' - Faculae vs. Sunspots
    "Three views of the Sun showing different levels of solar activity. The color table has been altered to enhance the appearance of the faculae (white regions) which are hotter than sunspots (red-black regions) and whose greater total area contribute to increasing the solar flux reaching the Earth."

    2. Understand variability of the Sun's luminosity"Small variations in the Sun's energy output can change weather and climate on Earth. During the 17th century, an abnormal period of low solar activity conincided with the "Little Ice Age" in northern Europe. Observations from space have shown that the total energy output of the Sun changes with variations in its magnetic cycle.

    "Solar-B will continuously monitor the buildup of sunspots as well as extremely small-scale magnetic structures as the Sun heads toward the next peak in its activity cycle."

    Also, Current Solar Data updated every 30 minutes.

    In response to your question, "Is the solar brightness dependant on how many solarspots are on the solar surface?" My answer would be "no" at this particular time though I am on a mission to explore further. I am going hunting tomorrow for more information.

    Have a nice day. Hope you enjoy exploring the websites.

    Thank you,
  5. Apr 7, 2010 #4


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    Re: Sunspots

    Partial answer -


  6. Apr 7, 2010 #5


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    Re: Sunspots

    Agreed with Astronuc, the sun is more energetic during peak periods of sunspot activity. The sun's magnetosphere is very active during these times.
  7. Apr 8, 2010 #6
    Re: Sunspots

    Moving onward with my quest for more information about sunspots, etc!:biggrin:

    World Book at NASA - Sun
    Updated:November 29, 2007
    by Editor:Brian Dunbar

    I’ve taken a snippet from four categories.

    Also, SOHO is a project of international cooperation between ESA and NASA.
    Here’s a snippet from an article:

    Science had an article worthy of presenting:
    Science 12 March 2010:
    Vol. 327. no. 5971, pp. 1350 - 1352
    DOI: 10.1126/science.1181990

    Last edited by a moderator: May 4, 2017
  8. Apr 8, 2010 #7
    Re: Sunspots

    A snippet from Earthobservatory- NASA

    Another snippet from an article, Changes in Solar Brightness Too Weak to Explain Global Warming, dated September 13, 2006 peeked my interest.

    Last edited by a moderator: May 4, 2017
  9. Apr 8, 2010 #8
    Re: Sunspots

    Nature had an article from August 27, 2009 entitled Sunspots stir oceans Variations in the Sun's brightness may have a big role in Pacific precipitation by Geoff Brumfiel.

    "Computer simulations are showing how tiny variations in the Sun's brightness can have a big influence on weather above the Pacific Ocean.

    "The simulations match observations that show precipitation in the eastern Pacific varies with the Sun's brightness over an 11-year cycle. However, the model does not indicate a relationship between solar activity and the rise in global temperature over the past century.

    "This is not a global warming thing," says Gerald Meehl, a modeller at the National Center for Atmospheric Research in Boulder, Colorado, and first author of the study. "But it does indicate that the Sun has a measurable impact on Earth's climate." The research is published this week in the journal Science1.

    "Although the Sun burns steadily, its shifting magnetic fields can lead to cooler, darker spots on the Sun's surface. The edges of these sunspots are much brighter than the rest of the Sun, and although this causes only a tiny increase in the Sun's total output of light over the 11-year cycle, researchers believe that it can influence Earth's climate. Many scientists think that a cold snap between 1645 and 1715, for example, may have been caused by an unusually spotless Sun. Researchers had also noticed that precipitation patterns in the Pacific Ocean seemed to vary with the 11-year sunspot cycle, with the average rainfall in the eastern Pacific seeming to drop during periods of high solar activity.

    "Solar puzzle

    "But how could such a tiny change in brightness influence weather over the world's largest ocean? Two theories have circulated in recent years. The first is that an increase in ultraviolet radiation associated with the brighter Sun changes the temperature of the upper echelons of the atmosphere. Those changes alter the winds over the tropics, and eventually lead to a drought in the east.

    "The second theory is that the increased brightness is heating the Pacific itself. The heating intensifies evaporation and rainfall in some regions, but creates cooling winds in the eastern part of the ocean, which prevents rain clouds from forming in those eastern areas.

    "Both theories seemed plausible, but when they were inserted separately into the models, neither produced an effect that was big enough to explain the observations, Meehl says. So he and his colleagues tried combining the two into a single model. "Sure enough, we got a much bigger response," he says.

    "The work is a good piece of modelling, but not all parts of the puzzle are in place, says Drew Shindell, a climate modeller at the NASA Goddard Institute for Space Studies in New York. Combining the two theories does seem to produce a model that replicates the magnitude of the sunspot cycle's impact. But the results of the simulation are far from being a perfect geographical match for real observations (see 'A model forecast'). "I think it's a nice step," Shindell says. "But there's clearly still a long way to go."

    ""I don't think we're claiming we've solved the problem," Meehl says. But he maintains that the model clearly replicates the general trends seen in the Pacific. He expects that as atmospheric scientists, oceanographers and others combine their different models in the coming years, their predictive power will only improve."

    Last edited: Apr 8, 2010
  10. Apr 28, 2010 #9
    Re: Sunspots

    Thank you so much for all your support guys!
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