Welcome to Astronomy & Telescope Astronomy

 
 

  Modules

· Home
· AvantGo
· Content
· Downloads
· Encyclopedia
· FAQ
· Feedback
· Forums
· Journal
· Members List
· Private Messages
· Recommend Us
· Reviews
· Search
· Statistics
· Stories Archive
· Submit News
· Surveys
· Top 10
· Topics
· Web Links
· Your Account
 

  Who's Online

There are currently, 7 guest(s) and 0 member(s) that are online.

You are Anonymous user. You can register for free by clicking here
 

  Search



 

  Languages

Select Interface Language:

 

  Random Headlines


Telescope
[ Telescope ]

·Astronomy: Telescope - HST-WHAT HST HAS SEEN
·Astronomy: Telescope - THE HUBBLE SPACE TELESCOPE
 

 
  Solar Activity: Astronomy: Solar Activity - THE SUNSPOT CYCLE
Posted on Tuesday, December 07 @ 13:37:08 CST by astronomy
 
 
  Solar Activity

THE SUNSPOT CYCLE

In the nineteenth century, German amateur astronomer Heinrich Schwabe was systematically scanning the Sun's surface, hoping to catch in transit a planet then thought to be orbiting inside Mercury.

To avoid mistakes, he tabulated all the sunspots he saw. Schwabe never found the planet—which does not, in fact, exist—but he did make the discovery that the number of sunspots rose and fell in a pattern lasting about a decade.

Today, after observation over many years, scientists have determined that sunspots follow an 11-year cycle, during which the number of spots goes from a minimum to a maximum. Solar astronomer reckon Cycle 0 as being the cycle that peaked in 1750. On this reckoning, Cycle 22 peaked in mid-1989 and end in late 1996, and Cycle 23 is expected to peak around 2001. Each cycle has an asymmetric shape, rising to maximum activity in about five years and declining over about six years.

At the start of a new cycle, the first spots appear around latitudes 35 degrees north and south. As the cycle progresses, sunspots become more numerous and appear at latitudes nearer the Sun's equator. By the end of the cycle, sunspots appear around 7 degrees north and south latitude. As one cycle is tailing oft, the first spots of the next cycle are already appearing at high latitudes.

Sunspots are highly magnetized, and astronomers have discovered that there is actually a 22-year magnetic cycle superimposed on the ordinary 11-year cycle. When they measure the magnetic fields of sunspots during any 11-year cycle, they find that the spots leading each group across the disk show opposite magnetic polarities in the two hemispheres. Then, in the next 11-year cycle, all leading spots switch polarity.

 
 
  Login

Nickname

Password

Don't have an account yet? You can create one. As a registered user you have some advantages like theme manager, comments configuration and post comments with your name.
 

  Related Links

· More about Solar Activity
· News by astronomy


Most read story about Solar Activity:
Astronomy: Solar Activity - THE SUNSPOT CYCLE

 

  Article Rating

Average Score: 0
Votes: 0

Please take a second and vote for this article:

Excellent
Very Good
Good
Regular
Bad

 

  Options


 Printer Friendly Printer Friendly

 Send to a Friend Send to a Friend

 

 
 
Associated Topics

Solar Activity
 
 


 
 
"Login" | Login/Create an Account | 0 comments
The comments are owned by the poster. We aren't responsible for their content.
 
 


 
 
No Comments Allowed for Anonymous, please register
 
 


 
  Astronomy & Telescope Astronomy

All logos and trademarks in this site are property of their respective owner. The comments are property of their posters, all the rest © 2004 by Astronomy & Telescope Astronomy
You can syndicate our news using the file backend.php or ultramode.txt