At a NASA press conference, Tuesday, astonished solar scientists told the media the sun’s solar wind was at its lowest extent for 50 years, after readings from the space probe Ulysses were published.
This news could affect climate and, according to NASA, space travel.
Winds of change
Among the measurements taken on Ulysses’ 2007 pole-pole sweep of the sun was of the solar plasma, the stream of charged particles – mostly electrons and protons – that periodically escape the sun’s gravity.
Ulysses’ most recent findings, published by NASA in Geophysical Research Letters, showed the solar magnetic strength was reduced by 20%. Near the Ullysses craft the fall was greater still: 36%.
While the cyclical nature of the solar wind is well known NASA say the extent of the present minimum is unprecendent in space age history.
"Right now, we are in a period of minimal activity that has stretched on longer than anyone anticipated", said one scientist in a press release.
For NASA the changing solar wind is significant because the heliosphere, the outer-extent of the solar wind, bubblewraps the solar system (and Earth) against penetration from cosmic rays.
With less bubblewrap spacecraft design will have to accommodate the increase in damaging cosmic rays, or human space travel might have to be reduced.
Watts up with the sun
For other scientists, the changing solar wind has significant implications for the Earth’s climate.
Particularly those scientists who look at correlations of sun spots and Earth temperature as proof of sun-driven climate change. They think this is a historic moment.
According to physicist Henrik Svensmark, who provided a causual link between solar activity and global cooling with his cosmic ray cloud seeding theory, more cosmic rays reaching the Earth should cool the Earth.
Cosmic ray seeded clouds reflect the sun’s heat high in the atmosphere before it reaches the Earth, causing the lower troposphere, where we live, to cool.
Meteorologist Anthony Watts, author of the popular wattsupwiththat blog, who attended the press conference for KPAY Radio, was shocked when NASA scientists said they did not know when the next maximum would be, or its size.
Watts had previously noticed what he calls a ‘step function‘ downward change in solar magnetic flux that occured in October 2005 and which has remained flat since. Was this the moment when the sun switched off the heat?
At the press conference Watts was not invited to ask a NASA scientist a question, so NASA’s own view on this remains a subject for another day.