It has been said that “the science is settled” regarding what we know about Earth’s atmosphere and climate. But recently scientists discovered that something we had accepted as a basic truth for a very long time is not true at all. One of the “basic truths” we all learned is that Earth’s atmosphere is “protected” from the solar wind by its magnetic field, unlike Mars which has lost most of its atmosphere due to the solar wind.
But when some space scientists compared notes recently, they discovered something startling:
“We said, ‘Oh my goodness — what we’ve been telling people about the magnetic shield is not correct.'”
And so what we thought to be true about our atmosphere, isn’t.
Irene Klotz, Discovery News
June 2, 2009 — Researchers were stunned to discover recently that Earth is losing more of its atmosphere than Venus and Mars, which have negligible magnetic fields.
This may mean our planet’s magnetic shield may not be as solid a protective screen as once believed when it comes to guarding the atmosphere from an assault from the sun.
“We often tell ourselves that we are very fortunate living on this planet because we have this strong magnetic shield that protects us from all sorts of things that the cosmos throws at us — cosmic rays, solar flares and the pesky solar wind,” said Christopher Russell, a professor of geophysics and space physics at the University of California, Los Angeles.
“It certainly does help in some of those areas but … in the case of the atmosphere, this may not be true,” he said.
Russel and others came to this realization while meeting at a comparative planetology conference last month.
“Three of us who work on Earth, Venus and Mars got together and compared notes,” Russell told Discovery News. “We said, ‘Oh my goodness — what we’ve been telling people about the magnetic shield is not correct.'”
The perpetrators are streams of charged particles blasting off the sun in what is known as the solar wind.
“The interaction of solar wind with Venus and Mars is pretty simple,” Russell said. “The wind comes in, carries a magnetic field, which wraps around the ionosphere of the planet. The ionosphere is basically dragged away.”
Complete article here at Discovery News