David Hosansky, NCAR & UCAR Media Relations | 21 September 2009 • The Sun is in one of its quietest periods in the last century, as noted in a NASA summary issued on 3 September and a recent article in the NCAR/UCAR Staff Notes newsletter. However, solar researchers at NCAR and elsewhere are in high gear.
The public is keenly interested in the Sun and its doings. “Sunspots” is one of the most frequent search terms bringing visitors to the NCAR/UCAR website. In our media office, we’ve seen an almost unprecedented amount of news regarding the Sun in recent months. Some examples:
The interface between a sunspot's umbra (dark center) and penumbra (lighter outer region) shows a complex structure with narrow, almost horizontal (lighter to white) filaments embedded in a background having a more vertical (darker to black) magnetic field. Farther out, extended patches of horizontal field dominate. For the first time, NCAR scientists and colleagues have modeled this complex structure in a comprehensive 3D computer simulation, giving scientists their first glimpse below the visible surface to understand the underlying physical processes. (Image courtesy Matthias Rempel, NCAR. See more images and video animations in the Sunspots Multimedia Gallery.)
Such research to help us better understand the solar cycle and its impacts on Earth may eventually lead the way to predicting these powerful geomagnetic storms.
Is the Sun warming our climate?
One question we're asked and see frequently elsewhere is whether the Sun may be responsible for global warming. Even when scientists include variations in solar output in computer models simulating recent climate—especially the rapid warming of the late twentieth century—they find the warming is caused primarily by emissions of carbon dioxide and other greenhouse gases. In fact, the Intergovernmental Panel on Climate Change concluded in 2007 that the combination of solar variations and volcanic eruptions likely had a cooling effect on Earth’s climate over the last 50 years (see page 5 of the Summary for Policymakers in the IPCC’s 2007 synthesis report).
While the recent research gives us new insights into the Sun, it does not alter the basic physics of climate change.