While its ancient Greek namesake had his own issues with winds, the gales braved by space probe Ulysses are on another scale entirely.

The joint ESA/NASA project has found solar wind is at its lowest levels since accurate recordings began 50 years ago, with strength of solar wind pressure down 20% on 1990s numbers. This stream of charged particles from the Sun creates a protective shield round the solar system, keeping pesky galactic cosmic rays away.

“With the solar wind at an all-time low, there is an excellent chance that the heliosphere will diminish in size and strength,” says Ed Smith, NASA’s Ulysses project scientist (press release). “If that occurs, more galactic cosmic rays will make it into the inner part of our Solar System.”

This isn’t great news for astronauts heading beyond the Earth though. You don’t want to catch too many galactic cosmic rays when you’re on the way to Mars.

It could be good for space boffins though. Smith adds, “It’s an opportunity for us to study changes in the sun which will give us newer insights into the origin of the solar wind and its relation to the solar magnetic field.” (Reuters.)

AP adds that the lower solar wind will enable satellites to stay orbiting for longer. There’s a flip side to this though, as researcher Nancy Crooker explains on VOA: “[Reduced solar activity] leads to the cooling of Earth’s upper atmosphere. And if Earth’s upper atmosphere is cooler, then there’s less drag on satellites up there, and this means we are left with more debris up there, which is also something astronauts have to look out for.”

The findings of the Ulysses team are published in GRL.

Image: McComas et al. GRL, 2008