As Grandmother used to say "If it isn't one tham ding it's another".
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.'">>>MORE