Astronomers who count sunspots have announced that 2008 is
now the "blankest year" of the Space Age.
As of Sept. 27, 2008, the sun had been blank, i.e., had no
visible sunspots, on 200 days of the year. To find a year with
more blank suns, you have to go back to 1954, three years before
the launch of Sputnik, when the sun was blank 241 times.
"Sunspot counts are at a 50-year low," says solar
physicist David Hathaway of the NASA Marshall Space Flight Center.
"We're experiencing a deep minimum of the solar cycle."
A spotless day looks like this:
(Article continues below)
The image, taken by the Solar and Heliospheric Observatory
(SOHO) on Sept. 27, 2008, shows a solar disk completely unmarked
by sunspots. For comparison, a SOHO image taken seven years
earlier on Sept. 27, 2001, is peppered with colossal sunspots,
all crackling with solar flares: image.
The difference is the phase of the 11-year solar cycle. 2001
was a year of solar maximum, with lots of sunspots, solar flares
and geomagnetic storms. 2008 is at the cycle's opposite extreme,
solar minimum, a quiet time on the sun.
And it is a very quiet time. If solar activity continues as
low as it has been, 2008 could rack up a whopping 290 spotless
days by the end of December, making it a century-level year
in terms of spotlessness.
Hathaway cautions that this development may sound more exciting
than it actually is: "While the solar minimum of 2008 is
shaping up to be the deepest of the Space Age, it is still unremarkable
compared to the long and deep solar minima of the late 19th
and early 20th centuries." Those earlier minima routinely
racked up 200 to 300 spotless days per year.
