The solar winds are now the lowest they’ve been in fifty years, meaning that the Sun’s effects on our solar system are also at an ebb. The Ulysses solar probe is providing these measurements, and the winds have not only lessened, but are also 13% cooler. Much more at BBC.
“This is a whole Sun phenomenon,” said Dave McComas, Ulysses solar wind instrument principal investigator, from Southwest Research Institute, San Antonio, US.
“The entire Sun is blowing significantly less hard – about 20-25% less hard – than it was during the last solar minimum 10-15 years ago.
“That’s a very significant change. In fact, the solar wind we’re seeing now is blowing the least hard we’ve see it for a prolonged time, since the start of those observations in the 1960s at the start of the space age.”
In addition to being calmer, the wind measured at Ulysses is 13% cooler.
However, judging from Sun activity data collected by non-satellite methods over the past 200 years, the current behaviour is thought to be well within the long-term norm.
Nonetheless, scientists expect the weakened wind to have a wide range of impacts.
Among the notable effects of this will be cooling of our upper atmosphere, and increased penetration through the solar system of external cosmic rays.