NASA on the State of the Sun
It Still Shines
The Ulysses spacecraft observed the weak solar winds, the constant, high-speed stream of particles that races from the sun, during a quiet period in the sun’s activity. The solar weather cycle affects Earth and other planets in the solar system.
“We know that the sun has been this cool before, this inactive before,” said Nancy Crooker, a physicist at Boston University in Boston, Mass., during a NASA teleconference on Tuesday. “But that was prior to the Space Age, so we didn’t have actual physical measurements until now.”
The solar wind, it found, is the weakest that’s been recorded since the beginning of the space age.
[D]uring the sun’s latest quiet period, the spacecraft found that the overall solar wind is 20 to 25 percent weaker, in terms of pressure and density, than during the previous solar minimum. Weaker solar winds mean a smaller and leakier heliosphere bubble, a protective sheath that surrounds the entire solar system. That means more background cosmic radiation gets through.
We certainly can ask what this means for the Earth. That doesn’t mean that NASA knows the answer. The former television meteorologist who blogs at Watts Up With That? (and who’s fast becoming the go-to guy for posts about Climate Change) posts:
The three general things that struck me most from this conference were:
1) We don’t know enough yet to predict solar cycles, we aren’t “in the game”, and “we don’t really know how big next maximum will be”.
2) We don’t see any link between the minimums, cosmic rays (which are increasing now) and earth’s climate. This was downplayed several times. Some quotes were “none of us here are experts on climate, and when asked about Galactic Cosmic Rays and Svensmark’s climate theory is the answer was “speculation”.
3) The minimum we are in now is “unique for the space age”, but “within norms for the last 200 years”, but we are also surprised to learn how much the solar wind has diminished on a truly “entire sun” scale.
He’s right – our ignorance about solar activity is showing.
The next mission that will return new, even better data about the sun has already been launched, and is being run out of the Applied Physics Lab. in Laurel MD. It’s called Stereo.