[DOC] [TLE] The Sunspot Cycle | UCAR Center for Science Education [PAR] The number of sunspots observed on the "surface" of the Sun varies from ... The 
cyclical variation in sunspot counts, discovered in 1843 by the amateur German 
astronomer Samuel Heinrich Schwabe, is called "the Sunspot Cycle". ... whereas 
a period when few sunspots appear is called a "solar minimum" (or "solar min"). [DOC] [TLE] Solar cycle - Wikipedia [PAR] The solar cycle or solar magnetic activity cycle is the nearly periodic 11-year 
change in the ... The solar cycle was discovered in 1843 by Samuel Heinrich 
Schwabe, who after 17 years of observations noticed a periodic variation in the 
average number of sunspots. Rudolf Wolf ..... The ratio of ultraviolet to visible light 
varies. [DOC] [TLE] Sunspots and climate - Atmospheric Science [PAR] Sunspots have a diameter of about 37,000 km and appear as dark spots ... There 
is also a superimposed fluctuation with a period of 25 months, i.e. a ... The 11-
year cycle of the number of sunspots was first demonstrated by Heinrich 
Schwabe ... radiant energy varies by up to 0.2% between the extremes of a 
sunspot cycle. [DOC] [TLE] Solar Max 2000.com : What is Solar Max? - Exploratorium [PAR] The average number of visible sunspots varies over time, increasing and 
decreasing ... An amateur astronomer, Heinrich Schwabe, was the first to note 
this cycle in 1843. ... more common and more intense during the period of solar 
maximum. ... Satellites move from a region of space that has one charge to an 
area that has... [DOC] [TLE] Living With A Star: 6: Space Weather: Solar Maximum [PAR] The average number of visible sunspots varies over time, increasing and 
decreasing on a ... An amateur astronomer, Heinrich Schwabe, was the first to 
note this cycle in 1843. ... become more common and more intense during the 
period of solar maximum. ... Power grids can be overloaded by these same 
bombardments. [DOC] [TLE] Maunder Minimum - Activity, Solar, Cycle, and Cycles - JRank Articles [PAR] The Maunder minimum is the name given to a period of extreme solar ... noted 
the presence of dark blemishes on the Sun's surface; these were the now ... 
Today we know that the number of sunspots rises and falls in a roughly 11-year 
cycle; ... it was not until 1843 that an amateur German astronomer, Heinrich 
Schwabe,... [DOC] [TLE] Sunspots : The solar system : Fact files : Learning : National ... [PAR] Sep 22, 2000 ... Despite these early observations, it was only after the invention of the telescope 
... of areas of lower temperature which are visible as dark spots. ... Their duration 
varies greatly. ... The number of sunspots follows a cyclical period of about 11 
years, something that was first noted by Heinrich Schwabe in 1843. [DOC] [TLE] Active Sun [PAR] The spots appear dark because they are slightly cooler than the surrounding 
photosphere. ... spots vary--sometimes growing, sometimes dissipating--over a 
period of .... Finally, by the end of the cycle, at solar minimum again, the total 
number has .... amateur astronomer, a pharmacist, Samuel Heinrich Schwabe, in 
1843. [DOC] [TLE] The Solar Cycle [PAR] Feb 25, 2015 ... Increases in the number of solar flares and coronal mass ejections .... Sunspots (
dark patches on the Sun where intense magnetic fields ... Figure 1: Sunspot 
groups observed each year from 1826 to 1843 by Heinrich Schwabe (1844). 
These ... cycle and shows that it varies in amplitude, shape, and length. [DOC] [TLE] The sunspot observations by Samuel Heinrich Schwabe - AIP [PAR] ... is not fully periodic, and only a large number of cycles can reveal the statistical 
.... Schwabe noted that the limb was not darker than the rest of the disk. He also... [DOC] [TLE] What's in store for sunspot cycle 24  Astro Bob [PAR] Sep 1, 2012 ... These vary from 9 to 14 years but the average is 11. In a typical cycle, the number 
of sunspots and solar storms begins at a ... Heinrich Schwabe in 1843 after he 
noticed sunspot numbers

Question: In 1843 Heinrich Schwabe noted that the number of these dark areas varies in a periodic cycle
Answer: sunspots