steve smith wrote:I've been considering the following points submitted to an email group I belong to and there's definitely something to think about regarding the "solar output" periodicity. We have no idea how the Sun and the Earth interacted over the last 10,000 years, for example. We have only a small snapshot in a moment of time to review.
Following the numbering scheme established by Wolf, the 1755-1766 cycle is traditionally numbered "1". The period between 1645 and 1715, a time during which very few sunspots were observed, is a real feature, as opposed to an artifact due to missing data, and coincides with the Little Ice Age. This epoch is now known as the Maunder minimum, after Edward Walter Maunder, who extensively researched this peculiar event, first noted by Gustav Spörer.
After two-plus years of few sunspots, even fewer solar flares, and a generally eerie calm, the sun is finally showing signs of life.
"I think solar minimum is behind us," says sunspot forecaster David Hathaway of the NASA Marshall Space Flight Center.
His statement is prompted by an October flurry of sunspots. "Last month we counted five sunspot groups," he says. That may not sound like much, but in a year with record-low numbers of sunspots and long stretches of utter spotlessness, five is significant. "This represents a real increase in solar activity."
In all of the hubbub around global warming, why haven't I seen this spectacular graphic display of sunspot activity before?
saturnine wrote:How accurate can sunspot counts from the 1700s actually be? What kind of tools were they using back then, or was it just somebody simply staring at the sun with the unaided eye?
edcrater wrote:This from wiki:
""A helioscope is an instrument used in observing the sun.
The helioscope was first used by Benedetto Castelli (1578-1643) and refined by Galileo (1564–1642). The method involves projecting an image of the sun onto a white sheet of paper suspended in a darkened room with the use of a telescope.
The first heliotropii telioscopici or helioscope was designed by Christoph Scheiner (1575 –1650) to assist his sunspot observations.""
Sounds like not much got past them observationally.
This seems to talk about coronal holes.The expansion and contraction happens way up in the Earth's thermosphere, the layer of the atmosphere that extends from about 60 to 300 miles (96.5 to 483 kilometers) above the planet's surface. The thermosphere is constantly interacting with the sun's upper atmosphere as it expands out into the solar system, said one of the researchers...
Extreme ultraviolet (UV) radiation from the sun was known to cause a 27-day expansion-and-contraction cycle by changing the thermosphere's density through heating.
Thayer and his team analyzed data from the German Challenging Minisatellite Payload (CHAMP) and the NASA Advanced composition Explorer satellite and found that the thermosphere also appeared to breathe every five, seven and nine days, "which was unexpected," Thayer said.
The researchers determined that the cause of these shorter expansions and contractions was high-speed winds generated by relatively cool pockets on the sun's surface known as solar coronal holes, which periodically rotate around the solar surface...
The changes in heating that cause the breathing can also impact climate, by triggering the upper atmosphere's "thermostat," as study team member Martin Mlynczak of NASA's Langley Research Center, Hampton, Va., put it. The added UV radiation heats up the atmosphere, in turn causing gaseous molecules to radiate that heat away in the form of infrared radiation.
This seems to talk about solar flares.The solar wind consists of electrically charged particles that flow out from the Sun in all directions. Even at their slowest, the particles race along at 200 km per second, taking less than 10 days to travel from the Sun to the Earth.
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