Why is Solar Cycle 24 Starting So Slowly?

  • Context: Graduate 
  • Thread starter Thread starter Astronuc
  • Start date Start date
  • Tags Tags
    Cycle Solar
Click For Summary

Discussion Overview

The discussion revolves around the slow start of Solar Cycle 24, examining the unusual behavior of solar activity, including sunspot counts and the implications of recent observations. Participants explore various theories and observations related to the solar cycle, its minimum and maximum phases, and the predictability of solar phenomena.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • Some participants note that the sunspot index for November 2009 was significantly lower than predictions, indicating a slow start to Solar Cycle 24.
  • Others highlight an increase in sunspot activity in December 2009, suggesting a potential awakening from a prolonged solar minimum.
  • A participant mentions that the recent solar minimum was both deep and long, with solar physicists acknowledging the odd behavior of the sun but lacking a clear explanation.
  • One participant expresses a personal view that the solar cycle's behavior seems normal, attributing the delayed start to long-cycle variations and questioning the predictability of solar activity.
  • There is mention of increased activity in March and April 2010, but a recent quiet period is also noted.

Areas of Agreement / Disagreement

Participants express a mix of opinions regarding the nature of Solar Cycle 24's start, with some viewing it as unusual and others considering it within normal variations. The discussion remains unresolved regarding the underlying causes of the observed solar behavior.

Contextual Notes

Participants reference various observations and predictions, but there are limitations in the understanding of the mechanisms behind the solar cycle's behavior, and the discussion reflects uncertainty about the predictability of solar phenomena.

Astronuc
Staff Emeritus
Science Advisor
Gold Member
2025 Award
Messages
22,581
Reaction score
7,536
The fingerprint of the new solar cycle
The new solar activity cycle still puzzles all solar physicists due to its very slow start. The sunpot index for November 2009 is still only 4.2, well below many predictions (SIDC predictions: SM=6, CM=13). Although, the number of spotless days decreased strongly compared to the last two years, with multiple but small sunspot groups.
. . . .
http://sidc.oma.be/news/119/welcome.html

A Long Filament Erupts (December 14, 2009)
http://soho.nascom.nasa.gov/pickoftheweek/old/11dec2009/


Solar Cycle 24 is off to a slow start.

http://www.spaceweather.com/images2...lank.gif?PHPSESSID=e4cknd2c58dnbuja23ubqbih15

http://www.spaceweather.com/images2009/15dec09/1035_anim2.gif?PHPSESSID=e4cknd2c58dnbuja23ubqbih15
 
Last edited by a moderator:
Astronomy news on Phys.org
So far, 65% of the days in December have brought sunspots--a sharp increase in percentages compared to earlier months of 2009 when sunspots were surpassingly rare. All six of December's sunspot groups have been members of new Solar Cycle 24. These numbers could herald the sun's awakening from the deepest solar minimum in nearly a century and a livelier sun in 2010.
Ref: http://www.spaceweather.com/archive.php?view=1&day=27&month=12&year=2009


Large Sunspot Group (December 18, 2009)
http://soho.nascom.nasa.gov/pickoftheweek/old/18dec2009/

For the first time in over a very quiet solar year, the Sun as seen by SOHO is sporting 5 active regions (Dec. 22, 2009). The brightest regions in the extreme UV image are magnetic active regions. And the brighter an area appears, then we know that its magnetic energy is stronger. Two of these regions are associated with dark sunspots when viewed in visible wavelengths; the other areas have not developed into sunspots yet. This activity could signal that the long solar minimum is beginning to give way to greater activity levels, but we will just have to wait and see.
Awakening Sun (December 25, 2009)
http://soho.nascom.nasa.gov/pickoftheweek/old/25dec2009/
 
May 27, 2010

Solar Scientists Agree That the Sun's Recent Behavior Is Odd, but the Explanation Remains Elusive
The most recent solar minimum was both long and pronounced. But why?

MIAMI—In very rough terms, the sun's activity ebbs and flows in an 11-year cycle, with flares, coronal mass ejections and other energetic phenomena peaking at what is called solar maximum and bottoming out at solar minimum. Sunspots, markers of magnetic activity on the sun's surface, provide a visual proxy to mark the cycle's evolution, appearing in droves at maximum and all but disappearing at minimum. But the behavior of our host star is not as predictable as all that—the most recent solar minimum was surprisingly deep and long, finally bottoming out around late 2008 or so.

Solar physicists here at the semiannual meeting of the American Astronomical Society this week offered a number of mechanisms to shed light on what has been happening on the sun of late, but conceded that the final answer—or more likely answers—remains opaque. . . . .
 
I've been watching this solar cycle almost daily on spaceweather.com and to me personally its seems pretty normal. Sure it was off to a delayed start but still within the bounds of long-cycle variations. I'm one of those with the opinion that you can't really predict the sun anyway. Our observation of it is way to short-lived for that. Anyhow, March and April was quite active in terms of sunspots if I recall correctly, plus many filaments that produced flares. The past few weeks have been a tad too quiet though...IMO.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
5K