15 October 2012
Lecture On The Sun
Wednesday, October 17, 2012 - 12:00pm
Watch online:
https://plus.google.com/events/csqif06cn5u5auhv7bbsigr471o
Dan Lubin
Climate Change: What's Going On With the Sun?
SETI Institute: 189 Bernardo Avenue #100, Mountain ViewWatch online:
https://plus.google.com/events/csqif06cn5u5auhv7bbsigr471o
Dan Lubin
SETI Institute
Throughout
the past century, while greenhouse gas (GHG) abundances have been
steadily increasing and influencing Earth’s climate, the Sun has
remained relatively bright and quiescent. Solar cycles have been
steadily active, with instantaneous sunspot numbers at solar maximum
exceeding 100 in every cycle since 1893 (Cycle 13). The climate warming
we have experienced since the beginning of the modern industrial era
cannot be attributed to the Sun. However, the recent minimum between
Cycles 23 and 24, and NASA predictions of a substantially lower sunspot
number at the 2013 solar maximum, suggest that the Sun’s recent bright
and quiescent period may be ending. Both autocorrelation studies of
recent solar cycles, and studies of solar analogs in nearby field stars,
suggest a >40% chance of the Sun entering a new Maunder Minimum
sometime in the Twenty First Century. During the historical Maunder
Minimum (1645-1715), meteorological data from Europe and proxy records
from global oceans indicate a substantially cooler climate, attributable
to decreased solar irradiance. In our lifetime, we may therefore see a
period of solar dimming in conjunction with increasing GHG abundances. A
new Maunder Minimum would not entirely offset the projected GHG-induced
warming (the GHG radiative forcing is at least three times larger than
best estimates of the solar irradiance decrease). Instead, the complex
interactions between radiative balance and atmospheric dynamics yield
unusual regional patterns of pronounced warming versus cooling. This
seminar will address the physical basis of climate change in the context
of both GHG and solar variability, and will also extend the discussion
to the influence of stellar variability upon habitable zones.
01 October 2012
October Sun 1x Visible Sunspots
OCTOBER 1st
Visible Sunspots over next couple of days!
Observe The Sun Safely - Never look at the Sun without a proper filter!
Solar Programs are held 1st Sunday of every Month 2:00-4:00 PM at Houge Park weather permitting
Over next couple of days one will still need good eyes and a good solar filter to see these (and welding glass wont cut it). Solar glasses are good, Solar Cards better.
Malika Carter: Sunspot image with her eyepiece projection system. Click photo to enlarge.
Clear Magnitude -26.73 skies Michael Packer
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