New measurements from the NASA/ESA spacecraft Ulysses show that the sun's current period of low activity goes beyond an extended dearth of sunspots. As AFP reports in a September 24 article:
The intensity of the sun's million-mile-per-hour solar wind has dropped to its lowest levels since accurate records began half a century ago, scientists say.As we have noted before, some scientists (such as Svensmark) draw a link between variations in solar wind and variations in cloud formation on our planet. Svensmark argues that increased cosmic radiation acts as a catalyst for cloud formation in earth's atmosphere -- in turn leading to a general cooling of the world's climate if the pattern persists.
Measurements of the cosmic blasts of radiation, ejected from the sun's upper atmosphere, were made with the Ulysses spacecraft, a joint mission between NASA and the European Space Agency (ESA).
The solar wind "inflates a protective bubble, or heliosphere, around the solar system," which protects the inner planets against the radiation from other stars, said Dave McComas, Ulysses' solar wind principal investigator and senior executive director at the Southwest Research Institute in San Antonio, Texas.
"With the solar wind at an all-time low, there is an excellent chance the heliosphere will diminish in size and strength," said Ed Smith, NASA's Ulysses project scientist at the Jet Propulsion Laboratory in Pasadena, California.
"If that occurs, more galactic cosmic rays will make it into the inner part of our solar system," added Smith.
If the current lapse in the solar wind continues, Svensmark may soon get all of the data he needs to support or refute his theory.