This post reports on a press conference today by NASA on the record low solar wind. The solar wind protects the earth from galactic cosmic rays. Galactic cosmic rays are theorized to influence cloud formation on earth. And cloud formation influences climate.
WASHINGTON, Sept 23, 2008 /PRNewswire-USNewswire via COMTEX/ — Data from the Ulysses spacecraft, a joint NASA-European Space Agency mission, show the sun has reduced its output of solar wind to the lowest levels since accurate readings became available. The sun’s current state could reduce the natural shielding that envelops our solar system.
"The sun’s million mile-per-hour solar wind inflates a protective bubble, or heliosphere, around the solar system. It influences how things work here on Earth and even out at the boundary of our solar system where it meets the galaxy," said Dave McComas, Ulysses’ solar wind instrument principal investigator and senior executive director at the Southwest Research Institute in San Antonio. "Ulysses data indicate the solar wind’s global pressure is the lowest we have seen since the beginning of the space age."
The sun’s solar wind plasma is a stream of charged particles ejected from the sun’s upper atmosphere. The solar wind interacts with every planet in our solar system. It also defines the border between our solar system and interstellar space.
This border, called the heliopause, surrounds our solar system where the solar wind’s strength is no longer great enough to push back the wind of other stars. The region around the heliopause also acts as a shield for our solar system, warding off a significant portion of the cosmic rays outside the galaxy.
"Galactic cosmic rays carry with them radiation from other parts of our galaxy," said Ed Smith, NASA’s Ulysses project scientist at the Jet Propulsion Laboratory in Pasadena, Calif. "With the solar wind at an all-time low, there is an excellent chance the heliosphere will diminish in size and strength. If that occurs, more galactic cosmic rays will make it into the inner part of our solar system."
This graphic from NASA illustrates how the solar wind has subsided.